Writing about aerospace and electronic systems, particularly with defense applications. Areas of interest include radar, sonar, space, satellites, unmanned plaforms, hypersonic platforms, and artificial intelligence.
In our never-ending quest to find some of the best free
software available, we’ve come up with 6 free programs that we think are
absolutely awesome! Most of the software I share with you is available for
Windows, Linux and Mac. As always, these programs are highly trusted and can
perform many of the same tasks as high-priced software. Subscribe! ▶ / @brettintech
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Free Software Playlist • Free Software Playlist
Here's a concise summary of the video transcript, which reviews six free software programs:
1. OBS Studio - Free, open-source screen recorder and livestreaming software - No watermarks, supports up to 60 FPS recording - Available for Windows 10/11, MacOS 11+, and Linux - Features customizable hotkeys and settings for both streaming and local recording
2. Photos Sketcher - Photo editing software that converts photos into artistic styles - Offers 20+ drawing styles including oil painting effects - Simple interface with zoom functionality and adjustable effect strengths - Includes text addition and undo/redo features
3. BleachBit - Free, open-source disk cleaner and privacy manager - Cleans browsers, temporary files, cookies, and cache - Supports thousands of applications - Available for Windows, Linux, MacOS, and email servers - Includes preview feature to review space to be cleaned
4. Kodi - Free, open-source media player and home theater software - Similar to Plex, can function as a media server - Supports streaming to compatible smart TVs and devices - Features extensive add-on system for customization - Available for Windows, Linux, Mac, Android, iOS, and Raspberry Pi
5. f.lux - Display color temperature adjustment software - Reduces blue light emission based on time and location - Customizable 24-hour presets - Compatible with Philips Hue lights - Available for Windows, with experimental versions for other platforms
6. LMMS (Linux MultiMedia Studio) - Free, open-source digital audio workstation - Includes instrument and effect plugins - Allows for creating melodies, beats, and mixing sounds - Available for Windows, Linux, and Mac
The video appears to be part of a series about free software recommendations, with links to all programs provided in the video description.
Mk24 MOD0 Radar aboard USS George Washington. All pictures by Yoshihiro Inaba.
US Navy's Mystery Radar System Finally Identified: Enhanced Defense for Pacific Carriers
The U.S. Navy's aircraft carriers operating in the Pacific have been equipped with a previously unidentified radar system, now revealed as the MK24 MOD0 Radar. The system, manufactured by RTX (formerly Raytheon), has been spotted on multiple carriers including the USS George Washington, which recently arrived at Yokosuka base in Japan.
The radar system, which was first noticed by observers in 2021, serves as a critical component of carrier self-defense systems, working in conjunction with the Phalanx CIWS and RAM missile systems. With installations on the port side, starboard side, and aft section of carriers, the MK24 MOD0 provides nearly 360-degree threat detection coverage.
According to defense analysts, the system appears to be derived from existing fighter aircraft radar technology, potentially the APG-79 AESA radar. This adaptation would enable detection ranges of approximately 150 kilometers and the ability to track small, low-observable threats.
The deployment of this advanced radar system comes amid growing strategic challenges in the Indo-Pacific region. Currently, all carriers equipped with the MK24 MOD0 are assigned to Pacific operations, highlighting the Navy's focus on enhancing defensive capabilities in this critical area.
"This system represents a significant upgrade to carrier self-defense capabilities," said Yoshihiro Inaba, who first identified the system during a media visit to the USS George Washington. "The ability to detect and track low-flying missiles and other threats is crucial for carrier operations in contested environments."
In October 2024, the aircraft carrier USS George Washington entered the U.S. Navy’s Yokosuka base (U.S. Fleet Activities Yokosuka) in Kanagawa Prefecture, Japan. The carrier is replacing the USS Ronald Reagan, which had been forward-deployed to Yokosuka since 2015. This marks the George Washington‘s
second deployment to Japan, the first being in 2009. Notably, the
vessel was equipped with a peculiar device. Resembling some sort of
antenna at first glance, the device was installed in three locations:
the starboard side, port side, and the aft section of the ship.
This device was first reported by The War Zone
in 2021 and had been speculated to be related to electronic warfare. As
of now, all carriers equipped with this device are deployed in the
Pacific region. Based on the author’s observations, the carriers
outfitted with this system include the USS George Washington, USS Carl Vinson, USS Theodore Roosevelt, USS Abraham Lincoln, and USS Ronald Reagan. Its true nature remained a mystery for some time, but during a media visit aboard George Washington in Yokosuka, the author uncovered the device’s true identity.
During the media visit to the flight deck, Naval News was
able to photograph the mysterious device mounted on the port side. A
nameplate attached to it read: “MK24 MOD0 Radar Sensor Assembly”. This
confirmed that the device is not related to electronic warfare but is,
in fact, a radar system.
In addition to its name, the nameplate also displayed the
manufacturer of the device: Raytheon, now known as RTX, a major U.S.
defense contractor. Naval News reached out to RTX to inquire on
the “MK24 MOD0”. The company’s response, while limited, sheds some
light on the role of the system:
“The system is part of the Carrier Self Defense system and aids CIWS and RAM for threat detection.”
In other words, this device appears to be a radar designed to detect
threats at greater distances or to identify low-flying missiles,
enhancing the effectiveness of systems like the Phalanx CIWS (Close-In
Weapon System) and RAM (Rolling Airframe Missile). Considering the
placement and angles of the devices, it is likely that they provide the
carrier with nearly 360-degree threat detection coverage.
What stands out is the question of what this device was based on.
Considering the rapid pace at which it was deployed on carriers, it
seems more likely to be a system developed swiftly and reliably using an
existing platform rather than one built entirely from scratch. Given
that the manufacturer is RTX, a logical candidate for its foundation
would be the APG-79 AESA radar. The size of the device, along with its
configuration—apparently divided into two major components: the front
antenna section and the processing unit behind it—further suggests that
it may have been developed based on a fighter aircraft radar system. If
this is the case, the radar is expected to have a detection range of
approximately 150 km or more, and it is likely capable of detecting
small, low-RCS (Radar Cross Section) missiles thanks to the use of
X-band.
In brief, Naval News believes the new MK24 MOD0 radar system
provides the aircraft carriers with a dedicated detection, tracking,
cueing capability for self-defense against low observable, very low
flying, and surface, threats. Given the advances in military
capabilities of China, which the U.S. Navy is facing in the Indo-Pacific
region, this system is an important upgrade to enhance aircraft
carriers’ defense and ensuring their operational effectiveness.
Yoshihiro Inaba is a Freelance Writer based in Shizuoka, Japan.
He is one of the few young military writers in Japan and is currently a
student studying international law (especially self-defense and use of
force) at a Japanese graduate school. He is particularly familiar with
Japan's Ground, Maritime and Air Self-Defense Forces.
Radio Frequency Fingerprint Identification (RFFI) is an emerging
technology that leverages the unique electromagnetic signals emitted by
wireless devices to identify and authenticate them. Like natural diamonds, each device has
distinct hardware imperfections that create a unique "fingerprint,"
making RFFI a powerful tool for securing Internet of Things (IoT)
ecosystems. As IoT devices proliferate across industries, from
healthcare to transportation, robust identification methods like RFFI
are essential to prevent unauthorized access and ensure system
integrity.
In a groundbreaking study published in the IEEE Transactions on Information Forensics and Security,
researchers Zhenxin Cai, Yu Wang, Guan Gui, and Jin Sha have unveiled a
pioneering framework for RFFI aimed at improving the security of
Internet of Things (IoT) devices. This innovative approach, termed
Adaptive Semantic Augmentation (ASA), addresses the challenges of
cross-domain signal identification, achieving unprecedented accuracy in
real-world scenarios.
The study, supported by grants from the Natural Science Foundation of
China and other institutions, integrates a multi-resolution spectrogram
decomposition strategy with a feature-sensitive multi-scale network. By
employing advanced techniques like two-dimensional discrete wavelet
transforms (2D-DWT) and instance-level semantic augmentation, the ASA
framework achieved remarkable accuracy levels of 93.05% and 98.90% on
two cross-domain datasets, outperforming conventional data augmentation
methods.
The research team comprises experts from Nanjing University and the
Nanjing University of Posts and Telecommunications. Zhenxin Cai, a
graduate student at Nanjing University, specializes in deep learning and
statistical signal processing. Yu Wang, a member of the IEEE and
principal-appointed professor, is celebrated for his contributions to
wireless communication optimization. Guan Gui, an IEEE Fellow, brings
extensive expertise in intelligent signal processing and has been
recognized as a Highly Cited Researcher. Jin Sha, a senior member of the
IEEE, contributes his experience in digital signal processing and
heterogeneous computing systems.
This study builds on prior research in RF-based IoT device
authentication and provides a scalable solution adaptable to varying
operational conditions. The ASA method’s robust performance across UAV
and WiFi datasets highlights its potential to enhance IoT security in
diverse applications, including urban environments and complex
electromagnetic conditions.
The team’s work not only pushes the boundaries of IoT security but
also sets the stage for future exploration of domain adaptation
techniques to further improve cross-scenario RFFI. Their contribution
underscores the critical role of advanced signal processing in securing
the ever-expanding IoT ecosystem.
Z. Cai, Y. Wang, G. Gui and J. Sha, "Toward Robust Radio Frequency Fingerprint Identification via Adaptive Semantic Augmentation," in IEEE Transactions on Information Forensics and Security, vol. 20, pp. 1037-1048, 2025, doi: 10.1109/TIFS.2024.3522758.
Abstract: Radio frequency fingerprint identification (RFFI) is regarded as one of the most promising techniques for managing and regulating Internet of Things (IoT) devices. This technology analyzes the unique electromagnetic signals emitted by wireless devices to enable precise identification and authentication. Most existing RFFI methods focus on RF signals collected in specific scenarios. However, in real-world applications, signals are often collected at different times or from varying deployment locations, leading to differences between the training and testing distributions. The study of RFFI methods under these conditions remains underexplored. To address this gap, this paper introduces a cross-domain RFFI framework centered on adaptive semantic augmentation (ASA). The framework integrates a computationally efficient multi-resolution spectrogram decomposition strategy with a feature-sensitive multi-scale network. The ASA method enhances RFFI accuracy in cross-domain settings by linearly interpolating between two distinct semantic features to create new semantics for further identification. The proposed approach leverages two-dimensional discrete wavelet transform (2D-DWT) to decompose the raw spectrogram into four sub-bands, followed by a multi-scale network to extract critical semantic features for the ASA method. Simulation results show that the proposed ASA method significantly improves Unmanned Aerial Vehicle (UAV) identification performance, achieving accuracies of 93.05% and 98.90% on two different cross-domain datasets, respectively, outperforming existing data augmentation (DA) methods. Furthermore, generalizability validation demonstrates that the proposed method performs outstandingly across other Internet of Things (IoT) applications. keywords: {Feature extraction;Training;Semantics;Spectrogram;Testing;Object recognition;Internet of Things;Radio frequency;RF signals;Fingerprint recognition;Adaptive semantic augmentation (ASA);radio frequency fingerprint identification (RFFI);multi-resolution spectrogram decomposition;multi-scale network}, URL: https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10816100&isnumber=10810755
Progress and Pitfalls: High-Power Lasers Face Critical Challenges in Counter-Drone Defense
Recent advances in directed energy weapons (DEWs) for counter-unmanned aircraft systems (CUAS) highlight both promising developments and persistent technical hurdles in the race to deploy effective drone defenses.
General Atomics' liquid-cooled HELADS system has demonstrated power levels reaching 150 kW, while Israeli defense companies have fielded operational systems like Iron Beam and Drone Dome. A significant breakthrough came from Chinese researchers who achieved 9 kW output power with impressive beam quality using D2O (heavy water) cooling technology.
However, major technical challenges remain before widespread deployment:
Power and Thermal Management: High-power lasers require substantial energy input and generate significant heat that must be efficiently dissipated. While liquid cooling shows promise, maintaining consistent beam quality during extended operations remains difficult.
Atmospheric Effects: Weather conditions like fog, rain, and atmospheric turbulence can severely degrade beam coherence over distance. Current adaptive optics systems only partially mitigate these issues.
Target Acquisition: Tracking and engaging small, fast-moving drones - especially in swarm scenarios - demands sophisticated sensor fusion and artificial intelligence capabilities that are still being developed.
"The physics challenges are significant," notes defense analyst [name withheld]. "While we've made progress with thermal management using advanced cooling techniques, maintaining beam quality at tactical ranges under real-world conditions remains a major hurdle."
Defense contractors are pursuing parallel approaches to address these challenges. Raytheon and Lockheed Martin are developing hybrid systems that combine high-power microwaves (HPM) with laser weapons, while Israeli companies focus on integrating DEWs into layered air defense networks.
The U.S. Department of Defense maintains a goal of fielding 300 kW-class systems, though current operational systems typically operate at much lower power levels. Industry experts suggest that practical, widely-deployed CUAS laser weapons may still be 3-5 years away from addressing all major technical challenges.
Major Technical Challenges for High-Power Lasers in Directed Energy Weapons (DEWs)
Power Generation and Thermal Management
Challenge: High-power lasers require substantial energy and generate significant heat. Efficient power sources and advanced cooling systems are essential to sustain operation without performance degradation.
Solutions: Advanced battery systems, capacitors, and compact cooling technologies such as liquid or phase-change systems.
Beam Quality and Atmospheric Effects
Challenge: Maintaining beam coherence over long distances is difficult due to atmospheric turbulence, particulates, and weather conditions (e.g., fog, rain).
Solutions: Adaptive optics and techniques like phased arrays or fiber lasers to correct and stabilize the beam in real time.
Target Tracking and Engagement
Challenge: Drone swarms are highly mobile and may include large numbers of small, fast-moving targets, complicating detection, tracking, and aiming.
Solutions: High-speed sensors, AI-enhanced tracking systems, and real-time data fusion to enable precision targeting.
Hardening Against Countermeasures
Challenge: Drones can use reflective or ablative coatings, maneuver unpredictably, or employ decoys to counter laser systems.
Solutions: Multi-wavelength lasers or mixed-use systems integrating other technologies like microwaves or kinetic interceptors.
Deployment Platforms and Scalability
Challenge: Lasers must be compact and robust enough for deployment on various platforms, including vehicles, ships, and aircraft.
Solutions: Modular designs and ruggedized systems that can be scaled for different operational requirements.
High-Power Microwave (HPM) Devices vs. Lasers for Drone Swarms
Advantages of HPM Devices:
Area Effect: HPM systems emit electromagnetic pulses that can disable multiple targets simultaneously, making them effective against swarms.
Minimal Target Precision: Unlike lasers, which require precise aim, HPM systems can disrupt electronics over a broad area.
Counter-Countermeasures: Reflective or ablative coatings are ineffective against HPM waves.
Disadvantages of HPM Devices:
Collateral Damage: They can inadvertently disable friendly or civilian electronic systems within the target area.
Shorter Effective Range: Typically less effective over long distances compared to lasers.
Power Demand: Like lasers, they require significant power and effective cooling systems.
Major Directed Energy Weapon Systems and Producers
United States:
Lockheed Martin
System: HELIOS (High Energy Laser and Integrated Optical-dazzler with Surveillance)
Platform: Ship-based, designed for drone and missile defense.
Raytheon Technologies
System: HELWS (High Energy Laser Weapon System)
Platform: Ground-based, scalable system for mobile platforms.
Northrop Grumman
System: Laser Weapon System Demonstrator (LWSD)
Platform: Ship-based, tested on USS Portland.
Europe:
Rheinmetall (Germany)
System: High-Energy Laser Weapon System
Platform: Integrated into naval and ground platforms.
MBDA (UK, Germany, France, Italy)
System: Dragonfire
Platform: Ground and ship-based laser weapon for anti-drone and missile defense.
China:
Producers: CETC (China Electronics Technology Group Corporation) and Norinco.
Systems: Silent Hunter and LW-30, designed for anti-drone applications and export.
Russia:
Producers: Almaz-Antey and Rostec.
Systems: Peresvet, focused on disabling optical systems and drone countermeasures.
Israel:
Producers: Rafael Advanced Defense Systems and Elbit Systems.
Systems: Iron Beam, a ground-based high-energy laser for short-range threats.
India:
Producer: Defence Research and Development Organisation (DRDO).
System: Directed Energy Systems for anti-drone and missile applications.
Conclusion
High-power lasers excel in precision and range, but challenges like power demands and atmospheric interference persist. HPM devices are promising for swarm scenarios due to their broad area effect but face range and collateral impact limitations. Countries worldwide are heavily investing in DEWs, with a mix of capabilities tailored for their strategic needs.
Israeli Systems
Israel has been actively developing and deploying directed energy weapons (DEWs) to counter evolving threats, particularly drones, rockets, and missiles. Israeli defense companies and organizations, such as Rafael Advanced Defense Systems and Elbit Systems, have been at the forefront of these efforts. Below are some of the notable systems:
1. Iron Beam (Rafael Advanced Defense Systems)
Overview:
Iron Beam is a high-energy laser system designed to complement Israel's layered missile defense systems, such as the Iron Dome, David's Sling, and Arrow systems. It focuses on intercepting low-cost, high-volume threats like rockets, mortars, and drones.
Key Features:
Laser Type: Solid-state, high-energy laser.
Targets: Rockets, artillery shells, drones, and UAVs.
Integration: Works alongside kinetic systems to reduce reliance on interceptor missiles.
Cost Effectiveness: Extremely low per-shot cost compared to traditional interceptors.
Development Status:
Demonstrated operational capabilities in recent trials.
Plans for deployment in multiple roles, including ground-based systems and integration into mobile platforms.
2. Elbit Systems’ High-Energy Laser Systems
Overview:
Elbit Systems has been developing laser-based systems for anti-drone applications and counter-missile roles. These systems focus on ground and airborne applications.
Key Systems:
C-MUSIC (Commercial Multi-Spectral Infrared Countermeasure): A directed energy system used to protect aircraft from heat-seeking missiles.
Anti-Drone Lasers: Ground-based laser systems capable of engaging and neutralizing multiple drones in real time.
Capabilities:
Multi-Layered Defense: Designed to work with radar and electronic warfare systems for enhanced threat detection and engagement.
High Mobility: Deployable on various platforms, including trucks and other vehicles.
3. Drone Dome (Rafael Advanced Defense Systems)
Overview:
The Drone Dome is an anti-drone defense system that integrates a high-energy laser with detection and tracking systems to neutralize drones.
Key Features:
Detection: Uses radar, RF sensors, and electro-optical/infrared (EO/IR) systems to detect and track drones.
Engagement: Equipped with a high-power laser to destroy drones at range.
Modular System: Can be deployed on fixed or mobile platforms.
Operational Use:
Deployed to protect critical infrastructure and military assets from drone threats.
Demonstrated effectiveness in intercepting drones during trials and real-world scenarios.
4. Scorpius (Israel Aerospace Industries - IAI)
Overview:
Scorpius is primarily an electronic warfare (EW) system but integrates directed energy capabilities to disable UAVs, communication links, and sensors.
Key Features:
Electronic Disruption: Focuses on jamming enemy communications and GPS.
Multi-Domain Operation: Capable of working across ground, air, and maritime environments.
Complementary Role: Works alongside kinetic and laser-based systems for layered defense.
Why Israeli Systems Are Noteworthy
Rapid Development: Israel has leveraged its extensive combat experience and innovative R&D ecosystem to develop systems tailored to asymmetric threats.
Cost Efficiency: Systems like Iron Beam aim to lower the cost per interception compared to traditional missiles.
Operational Success: Many Israeli systems have proven their capabilities in active conflicts, showcasing their reliability and effectiveness.
Export Potential: Israel actively markets these systems globally, offering them to allies and countries facing similar threats.
While specific technical details like Effective Radiated Power (ERP) at beam center and beamwidth for military laser systems are often classified or not publicly disclosed, some estimations can be made based on general knowledge, open sources, and typical system performance characteristics.
Below is a table summarizing key Israeli DEWs with approximate values based on publicly available data:
System
Producer
Type
Estimated Power Output
Beamwidth (Degrees)
ERP at Beam Center
Primary Targets
Iron Beam
Rafael Advanced Defense Systems
Solid-State Laser
~100–150 kW
~0.01–0.05°
~1–10 MW (approx.)
Rockets, Mortars, Drones
Drone Dome
Rafael Advanced Defense Systems
Solid-State Laser
~20–50 kW
~0.1–0.2°
~100–500 kW (approx.)
Drones, UAVs
Elbit Anti-Drone Laser
Elbit Systems
Solid-State Laser
~30–100 kW
~0.05–0.1°
~500 kW–5 MW (approx.)
Drones, UAVs
C-MUSIC
Elbit Systems
Infrared Laser
~10–20 kW
~0.5°
~100–200 kW (approx.)
MANPADS (airborne threats)
Notes:
Estimated Power Output: Indicates the laser's continuous power or peak output in kilowatts (kW).
Beamwidth: Represents the angular width of the laser beam, often narrow for high-precision systems. Smaller beamwidths result in higher energy density at the target.
ERP at Beam Center: Derived based on power output and beamwidth. A narrower beamwidth concentrates more energy at the beam center, resulting in higher ERP values.
Targets: Systems are optimized for specific threat profiles, such as small drones, rockets, or missiles.
Methodology for Estimates:
Beamwidth and ERP: ERP is proportional to the power output divided by the beam's angular spread. For lasers, high precision (narrow beamwidth) leads to higher ERP.
Classified Data: Actual ERP and beamwidth may vary due to proprietary technologies, classified optimizations, and adaptive optics.
Solid-State Laser Technology: Overview
Solid-state lasers (SSLs) are a type of laser that uses a solid gain medium, such as a crystal or glass doped with rare-earth elements (e.g., neodymium or ytterbium), to amplify light and generate a coherent laser beam. These lasers are a cornerstone of modern directed energy weapon (DEW) systems due to their robustness, scalability, and efficiency.
Key Components of Solid-State Lasers
Gain Medium
Material: Crystals (e.g., Nd:YAG, Yb:YAG) or glass doped with rare-earth ions.
Role: Amplifies the light through stimulated emission.
Pump Source
LED or laser diodes provide the energy to excite the gain medium.
Optical Resonator
Mirrors placed around the gain medium to sustain and amplify the laser beam.
Cooling System
Removes waste heat generated during operation, critical for maintaining beam quality and preventing damage.
Beam Combining (if applicable)
Methods such as spectral or coherent beam combining are used to merge multiple laser beams into a single, high-power output.
Advantages of Solid-State Lasers
Efficiency: High electrical-to-optical efficiency, especially with modern fiber or diode-pumped designs.
Scalability: Can achieve higher power outputs by combining multiple laser modules.
Compact Design: Suitable for deployment on ground vehicles, ships, and aircraft.
Low Maintenance: No moving parts in the gain medium, increasing system durability.
HELADS (High Energy Liquid Laser Area Defense System)
Developer: General Atomics Electromagnetic Systems (GA-EMS)
Overview:
HELADS is a liquid-cooled solid-state laser system developed to provide scalable and high-power laser capabilities for directed energy applications, particularly in defense against aerial and missile threats. It represents an advanced approach to solid-state laser design.
Key Features of HELADS
High Power Output
Capable of delivering power levels in the 150 kW range or higher, making it suitable for engaging rockets, drones, and even larger targets like missiles.
Liquid-Laser Gain Medium
Uses a proprietary liquid gain medium that enhances heat dissipation compared to traditional solid-state crystals or glass. This allows for higher power scaling without the thermal distortion common in conventional solid-state lasers.
The system is designed to fit into compact spaces, such as aircraft, ground vehicles, or ships.
Beam Combining Technology
Employs advanced methods like coherent beam combining to achieve high beam quality and power density, essential for engaging distant or small targets.
Operational Applications
Drone Swarms: Precise targeting and neutralization of UAVs in swarm scenarios.
Missile Defense: Effective against small, fast-moving targets like incoming missiles.
Artillery and Mortars: Disabling or destroying incoming projectiles in real time.
Advantages of HELADS Over Conventional SSL Systems
Thermal Management: The liquid gain medium significantly reduces thermal distortion, enhancing beam quality and system reliability.
Power Scaling: Scalable to higher power outputs without requiring exponentially larger systems.
Platform Versatility: Compact enough for integration into various military platforms.
Comparison with Fiber Lasers and Other SSLs
Feature
HELADS
Fiber Lasers
Conventional SSLs
Cooling Efficiency
Superior (liquid-cooled)
Moderate (fiber-cooled)
Lower (crystal or slab-cooled)
Beam Quality
High (coherent combining)
High (fiber combining)
Moderate
Power Scalability
High
Moderate
Moderate
Platform Integration
High (compact design)
High
Moderate
Development and Deployment
General Atomics has demonstrated the HELADS system in tests, showing its ability to engage various targets effectively. It is part of a broader effort to equip the U.S. military with next-generation DEWs for layered defense systems. HELADS remains a key competitor in the race for scalable, high-energy laser systems, alongside efforts by Lockheed Martin and Raytheon.
Sources
Here is a formal list of citations with hyperlinks for the information provided:
General Atomics' High-Energy Liquid Laser Area Defense System (HELLADS)
General Atomics Electromagnetic Systems. High-Energy Laser Completes Beam Quality Evaluation. Available at: GA.com
General Atomics Electromagnetic Systems. HELLADS Weapon System Demonstrator Information. Available at: GA.com
Solid-State Laser Technology in Directed Energy Weapons
United Nations Institute for Disarmament Research. Directed Energy Weapons: A New Look at an Old Technology. Available at: UNIDIR.org
U.S. Congressional Research Service. Directed Energy Weapons: Background and Issues for Congress. Available at: FAS.org
General Atomics' Developments in Laser Weapon Systems
Hambling, David. General Atomics' Liquid Laser Could Win High-Energy Weapon Race. Available at: Forbes
General Atomics to Build a Second 150 kW HELLADS Military Laser for the U.S. Navy. Available at: Laser Focus World
General Atomics' Corporate Information
General Atomics. Official Company Website. Available at: GA.com
Relevant News Articles on Laser Systems
Why Lasers Could Be Kryptonite for Drones. Available at: Wall Street Journal
Defence Groups Bet Big on Drone-Destroying Laser Weapons. Available at: Financial Times
Military Laser Hits Drones 'for 10p a Shot' in Successful Test. Available at: The Times
Technical Risks and Advancements in SSL
The development of high-power
diode lasers has enabled new solid-state laser concepts such as
thin-disk, fiber, and Innoslab lasers based on trivalent ytterbium as
the laser-active ion, resulting in a tremendous increase in the
efficiency and beam quality of continuous-wave lasers compared to
previously used technologies.
However, the onset of nonlinear effects, thermal effects, and
laser-induced damages have limited the power scaling of various
solid-state lasers, which has limited the overall performance of the
systems with the conjunction of the transmission optics and free-space
laser beam propagation.
Since the advent of laser technology in 1960, solid-state laser
technology has made tremendous advancements, leading the way in peak
power among various types of lasers.
The directed energy field, including fiber lasers, solid-state lasers,
and alkali lasers, has continued to see updates and advancements in
technology.
Some Readings on SSL DEW
[Arabgari, S. (2022). Thermal analysis of side-pumped
direct-liquid-cooled Nd: YAG thin-disk lasers.
ScienceDirect.com](https://www.sciencedirect.com)
This paper examines thermal effects in side-pumped direct-liquid-cooled Nd:YAG thin-disk lasers (SDNTDLs), which are a key challenge in achieving high-power, near-diffraction-limited laser output. The research uses a multiphysics model to analyze thermal distributions and effects. Key findings include:
1. The temperature distribution remains relatively smooth despite non-uniform pumping 2. The thin thermal boundary layer prevents thermal interaction between adjacent disks 3. When using D2O (heavy water) as coolant, the disk's wavefront aberration exceeds that of the fluid 4. The wavefront aberrations from different components (fluid and disk) can actually compensate for each other 5. The research provides insights for improving beam quality through design optimization
The study aims to bridge the gap between current capabilities (9 kW with beam quality β = 9.5) and the US Department of Defense's goal of 300 kW-class laser output.
The paper by Arabgari examines thermal effects in side-pumped direct-liquid-cooled Nd:YAG thin-disk lasers (SDNTDLs), using multiphysics modeling to understand thermal distributions and their impact on laser performance. Key findings show that using D2O (heavy water) as coolant improves performance compared to siloxane solutions, with wavefront aberrations from different components being able to compensate for each other.
Jiayu
Yi, B O Tu, Xiangchao An, X U Ruan, Jing Wu, Hua Su, Jianli Shang, Y I
Yu, Yuan Liao, Haixia Cao, Lingling Cui, Qingsong Gao, Kai Zhang "9 kilowatt-level direct-liquid-cooled Nd:YAG multi-module QCW laser" https://doi.org/10.1364/OE.26.013915 Abstract An
average 9 kilowatt-level direct-D 2 O-cooled side-pumped Nd:YAG
multi-disk laser resonator at QCW mode with a pulse width of 250μs is
presented, in which the straight-through geometry is adopted the
oscillating laser propagates through 40 Nd:YAG thin disks and multiple
cooling D 2 O flow layers in the Brewster angle. Much attention has been
paid on the design of the gain module, including an analysis of the
loss of the laser resonator and the design of the Nd:YAG thin disk.
Experimentally, laser output with the highest pulse energy of more than
20 J is obtained at a repetition frequency of 10 Hz. At high repetition
frequency, the average output power 9.8 kW with η o-o = 26% and 9.1 kW
with η o-o = 21.8% are achieved in the stable resonator and unstable
resonator, respectively, and in the corresponding beam quality factor β
stable = 14.7 and β unstable = 9.5 respectively. To the best of our
knowledge, this is the first demonstration of a 9 kilowatt-level
direct-liquid-cooled Nd:YAG thin disk laser resonator.
The second paper by Yi et al. presents experimental results demonstrating a 9 kilowatt-level direct-D2O-cooled side-pumped Nd:YAG multi-disk laser. Key achievements include:
- Output power of 9.8 kW with 26% efficiency in stable resonator mode
- Output power of 9.1 kW with 21.8% efficiency in unstable resonator mode
- Beam quality factors of β=14.7 (stable) and β=9.5 (unstable)
- System uses 40 Nd:YAG thin disks cooled by flowing D2O
- Novel design features include dual gain modules with opposite flow directions to compensate for thermal effects
- Compact design with volume under 0.4 m³
This research represents significant progress in high-power solid-state laser development, with potential applications in industrial, scientific and defense sectors.
C. B. Cobb and S. F. Adams, "Lightweight, compact superconducting power sources for solid state high energy lasers," IECEC '02. 2002 37th Intersociety Energy Conversion Engineering Conference, 2002., Washington, DC, USA, 2002, pp. 66-69, doi: 10.1109/IECEC.2002.1391977. Abstract: The air force is considering advanced compact electrical power systems for many future airborne DEW concepts to capitalize on the advantages of electrical DEW. High output electrical generators, employing superconductor wire technology, are being investigated as a possible solution. Generators with high temperature superconducting (HTS) wire would be significantly lighter weight and more compact than conventional copper wire-wound generators for this high level of power. keywords: {Solid state circuits;Power lasers;Solid lasers;High temperature superconductors;Power generation;Diodes;Superconducting filaments and wires;Pump lasers;Weapons;Superconducting photodetectors}, URL: https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=1391977&isnumber=30300
S. Adams and J. G. Nairus, "Energy conversion issues for airborne directed energy weapons," IECEC '02. 2002 37th Intersociety Energy Conversion Engineering Conference, 2002., Washington, DC, USA, 2002, pp. 61-64, doi: 10.1109/IECEC.2002.1391975. Abstract: The ability of an airborne directed energy weapon (DEW) to effectively strike a target depends strongly on the ability to develop, deliver, and manage the required energy for the onboard DEW source. The energy flow within various generic airborne DEW systems is examined from power generation to waste heat management. Each airborne DEW system is analyzed by considering the energy flow through an example configuration of generalized DEW system components. The numbers used in the analysis are not representative of any airborne DEW system under development, but simply allow for an illustration of energy flow within a DEW system of advanced power level. keywords: {Energy conversion;Weapons;Chemical lasers;Waste heat;Energy management;Reservoirs;Power lasers;Masers;Fuels;Solid lasers}, URL: https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=1391975&isnumber=30300
P. N. Barnes, G. L. Rhoads, J. C. Tolliver, M. D. Sumption and K. W. Schmaeman, "Compact, lightweight, superconducting power generators," in IEEE Transactions on Magnetics, vol. 41, no. 1, pp. 268-273, Jan. 2005, doi: 10.1109/TMAG.2004.838984. Abstract: Many future military systems will depend heavily on high electrical power input ranging from hundreds of kilowatts up to the multimegawatt level. These weapon systems include electromagnetic launch applications as well as electrically driven directed energy weapons (DEW), such as high-power microwaves and solid-state lasers. These power generation subsystems must often be packaged using limited space and strict weight limits on either ground mobile or airborne platforms. Superconducting generators made of high-temperature superconductors (HTS) will enable megawatt-class airborne power systems that are lightweight and compact. Also discussed briefly are new advances in HTS conductors and refrigeration systems furthering the development of HTS power systems. keywords: {Power generation;High temperature superconductors;Superconducting microwave devices;High power microwave generation;Weapons;Power systems;Electromagnetic launching;Solid lasers;Packaging;Conductors;Generators;high-temperature superconductors;superconducting filaments and wires;superconducting tapes}, URL: https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=1381551&isnumber=30122
P. N. Barnes, G. L. Rhoads, J. C. Tolliver, M. D. Sumption and K. W. Schmaeman, "Compact, lightweight, superconducting power generators," 2004 12th Symposium on Electromagnetic Launch Technology, Snowbird, UT, USA, 2004, pp. 158-163, doi: 10.1109/ELT.2004.1398066. Abstract: Many future military systems will depend heavily on high electrical power input ranging from 100's kilowatts up to the multimegawatt level. These weapon systems include electromagnetic launch applications as well as electrically driven directed energy weapons (DEW), such as high power microwaves and solid state lasers. These power generation subsystems must often be packaged using limited space and strict weight limits on either ground mobile or airborne platforms. Superconducting generators made of high temperature superconductors (HTS) will enable megawatt-class airborne power systems that are lightweight and compact. Also discussed briefly are new advances in HTS conductors and refrigeration systems furthering the development of HTS power systems. keywords: {Power generation;High temperature superconductors;Superconducting microwave devices;High power microwave generation;Weapons;Power systems;Electromagnetic launching;Solid lasers;Packaging;Conductors}, URL: https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=1398066&isnumber=30395
J. Weingarten, "ATLAS Pixel Detector System Test and Cosmics Run," in IEEE Transactions on Nuclear Science, vol. 56, no. 4, pp. 2543-2548, Aug. 2009, doi: 10.1109/TNS.2009.2025174. Abstract: The central component of the ATLAS inner tracker is the pixel detector. It consists of three barrel layers and three disk-layers in the endcaps in both forward directions. This amounts to a total active area of about 1.7 m2 with over 80 million pixel cells. The huge number of readout channels necessitates a very complex services infrastructure for powering and readout as well as for detector and operator safety. The complete pixel detector system has been tested for the first time in a large scale system test at CERN from September 2006 to January 2007. An overview of the system test setup is given and key results are presented. keywords: {Detectors;System testing;Optical fibers;Control systems;Optical attenuators;Optical noise;Vertical cavity surface emitting lasers;Large Hadron Collider;Silicon;Voltage control;Semiconductor detectors;solid state detectors}, URL: https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=5204518&isnumber=5204508
High Power Laser Science and Engineering is
a Gold Open Access peer reviewed journal that seeks to uncover the
underlying science and engineering in the fields of: high energy density
physics, high power lasers, advanced laser technology, and applications
and laser components. The journal was formed in 2013 as a joint venture
between Cambridge University Press (CUP), Cambridge, UK and Chinese
Laser Press (CLP), Shanghai, China. The journal is published on-line
with one volume per year. Under the stewardship of Editors-in-Chief from
both China and the UK the journal has established itself as an
internationally recognised publication. ISSN: 2095-4719 (Print),
2052-3289 (Online) Editors:
Colin Danson
AWE and Centre for Inertial Fusion Sciences, Physics Department, Imperial College London, UK,
and
Jianqiang Zhu
Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, China
Frontiers | Editorial: Advanced high power solid-state laser technology
Since
the first demonstration of lasers, continuous progress in the
development of laser technology, especially solid-state laser
technology, has led to numerous new applications and capabilities.
Solid-state lasers, including fiber lasers, crystal lasers, and ceramic
lasers, have the unique advantage of high efficiency, reliability,
flexibility and robust configuration. The rapid development of the
solid-state laser technology has been enabled by the introduction of
novel materials, components, advanced laser technology and system
design. Tremendous new applications have been advanced, including the
high order nonlinear physics interactions, free space and quantum
communications, LIDAR for autonomous vehicles, beam projecting and
steering, and materials processing. However, the onset of nonlinear
effects, thermal effects, and laser-induced damages have limited the
power scaling of various solid-state lasers, which limited the overall
performance of the systems with the conjunction of the transmission
optics and free-space laser beam propagation. Novel concepts and designs
have been continuously proposed and demonstrated by global researchers
to explore approaches circumventing the aforementioned limitations. This
Research Topic aims to provide a comprehensive view of the latest
advances in solid state laser development along with the most recent new
applications.
After the initiating of this Research Topic, 8
high-quality papers has been accepted for publication, which are
representative of the broad range of technology advances that this
Research Topic strives to facilitate, and we trust readers will find
them stimulating and enlightening. We are thankful to all authors and
reviewers for their excellent contributions. We would also like to thank
the Frontiers staff for their outstanding work throughout the launch of
this Research Topic as well as the review and production processes.
High
quality robust mid-infrared laser has broad scientific and practical
application value, which can be achieved by optical parametric
oscillator through pumping nonlinear frequency crystal with
near-infrared solid state laser [1–3]. The 2.79 μm Er,Cr:YSGG crystal has been proven to be a high efficiency flash-lamp pumped laser medium [4], and Jiang et al. has designed a new type of lithium niobate (LiNbO3)
acousto-optic Q-switched Er,Cr:YSGG laser with pliane-convex resonator,
where the laser performance has been improved significantly. When the
laser operated at free running region, the maximum values of pulse
energy was 160 mJ at 60 Hz, compared with the plane-parallel resonator,
the pulse energy was increased by 2 times in the plane-convex resonator.
When the LiNbO3 Q-switched laser operated at 60 Hz, the
maximum pulse energy was 8.5 mJ, and the minimum pulse duration was
60.8 ns, which generates the corresponding peak power of approximately
140 kW.
Fiber lasers and amplifiers are important branch of
solid-state laser, which has attracted more and more attention since
their inception, both as stand-alone sources and as parts for more
complex lasers and systems [5].
Four articles on high power fiber lasers and their applications appear
in this Research Topic. Fiber materials are at the core of the
technology [6], and consequently fiber materials and its design continues to be central to this article group. An et al.
focus on a common phenomenon in the
modified-chemical-vapor-deposition-fabricated fibers, and present a
numerical analysis of the dip effect on high-power-related parameters
for the first time, which reveled that the dip offers a flexible way to
suppress the non-linear effects and filter the higher-order modes by
optimizing the dip parameters. The next two papers addressed the
transverse mode instability (TMI), since this represent one of the
primary obstacles to power scaling fiber laser systems with
diffraction-limited beam quality [7, 8]. Chai et al. demonstrate a direct pump modulation to mitigate TMI in a 30 μm-core-diameter all-fiber laser oscillator while Lu et al.
propose to mitigate TMI by controllable mode beating excitation with a
photonic lantern, which increased the TMI threshold by nearly four
times. Narrow linewidth fiber lasers are a hot Research Topic in fiber
laser area [9, 10], and the last paper from Chu et al.
reported a 3-kW PM fiber laser at <10 GHz linewidth with the
polarization extinction ratio of 96% and beam quality of 1.156, which is
the highest output power ever reported with approximately 10 GHz
linewidth.
Optical vortices, finding a growing number of
applications ranging from industrial laser machining to optical
communications, have aroused ever-increasing interest among both
scientific and engineering communities [11, 12],
which opens new application avenue for the solid-state lasers. The next
group of papers in this Research Topic focused on “generating of
optical vortices.” Lin et al. design a folded resonant cavity to generate a helicity and topological charge tunable vortex laser, and the HGθm,0 beam (m = 1 to 10 and θ = −90°–90°]) and the vortex beam (topological charge l from ±1 to ±10 and left/right helicity) were flexibly achieved. Li et al.
investigated the power scaling of optical vortices, and reported
1.89 kW cylindrical vector beams by metasurface extra-cavity conversion
of a narrow linewidth all-fiber linearly-polarized laser, which is the
highest power of cylindrical vector beams generated from fiber laser.
The
remaining one paper in this Research Topic is about one of the key
technology in high power solid-state lasers-adaptive optics technology [13].
In the adaptive optics control of high-power laser systems, an
indispensable part is deformable mirrors, which are commonly used as the
corrector to correct wavefront aberration, and suffer performance
degradation under high-power laser irradiation [14]. Zheng et al.
introduce the dual magnetic connection deformable mirrors, which could
effectively suppress the laser-induced distortion and maintain good
wavefront correction capability.
In summary, one can see that
significant progress has been made in high power solid-state laser area,
and more and more exciting applications are expected in the future.
This Research Topic collects the latest breakthrough of the community
working in these fields, showing the still vivid and inspiring
development of high power solid-state laser.
The author(s) declare that no financial support was received for the research, authorship, and/or publication of this article.
Conflict of interest
The
authors declare that the research was conducted in the absence of any
commercial or financial relationships that could be construed as a
potential conflict of interest.
Publisher’s note
All
claims expressed in this article are solely those of the authors and do
not necessarily represent those of their affiliated organizations, or
those of the publisher, the editors and the reviewers. Any product that
may be evaluated in this article, or claim that may be made by its
manufacturer, is not guaranteed or endorsed by the publisher.
2.
Antipov O, Kositsyin R, Kal’yanov D, Kolker D, Larin S. 3.9-μm optical
parametric oscillator based on MgO:PPLN pumped at 1966 nm using a
high-repetition-rate Tm3+:Lu2O3 ceramic laser. In: 2017 Conference on Lasers and Electro-Optics Europe and European Quantum Electronics Conference (CLEO/Europe-EQEC); 25-29 June 2017; Munich, Germany (2017). paper CD_P_50.
3.
Antipov O. Wavelength tuned mid-IR lasers based on single-crystalline
or polycrystalline Cr2+-doped ZnSe with 1.9-2.1 μm pumping. In: International Conference Laser Optics (ICLO); 20-24 June 2022; Saint Petersburg, Russian Federation (2022).
6.
Chen X, Yao T, Huang L, An Y, Wu HS, Pan Z, et al. Functional fibers
and functional fiber based components for high-power lasers. Adv Fiber Mater (2023) 5:59–106. doi:10.1007/s42765-022-00219-7
7.
Tao RM, Wang XL, Zhou P. Comprehensive theoretical study of mode
instability in high-power fiber lasers by employing a universal model
and its implications. IEEE J Sel Top Quan Electron (2018) 24:1–19. doi:10.1109/jstqe.2018.2811909
9. Ma PF, Yao TF, Chen YS, Wang GJ, Ren S, Song J, et al. New progress of high-power narrow-linewidth fiber lasers. Proc SPIE (2022) 12310:123100E. doi:10.1117/12.2643929
11.
Zhi D, Hou TY, Ma PF, Ma YX, Zhou P, Tao R, et al. Comprehensive
investigation on producing high-power orbital angular momentum beams by
coherent combining technology. High Power Laser Sci Eng (2019) 7:e33. doi:10.1017/hpl.2019.17
12. Yu J, Zhang P, Ruffato G, Lin D. Editorial: optical vortices: generation and detection. Front Phys (2022) 10:1026004. doi:10.3389/fphy.2022.1026004
14.
Ma HT, Zhou Q, Xu XJ, Du SJ, Liu ZJ. Full-field unsymmetrical beam
shaping for decreasing and homogenizing the thermal deformation of
optical element in a beam control system. Opt Express (2011) 19:A1037–A1050. doi:10.1364/oe.19.0a1037
/ @brettintech
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