The Navy desires a short wave infrared high energy laser illuminator and coupled range-gated imaging sensor, including optics, operating in 1.9-2.5 micron wavelength to increase engagement ranges in adverse marine atmospheric conditions that include absorption, Mie and Rayleigh scattering, thermal blooming, etc. and able to operate in continuous wave (CW) or pulsed operation modes – at a variable power level up to kilowatt powers (average). Adjustable wavelength tunability to match to optimal atmospheric penetration and transmission within the band specified is required. If the entire band is not accessible, then rationale must be provided for limitation or selections made. In addition, it requires these to be ruggedized, so they are suitable to be installed on maritime platforms (i.e., ships, USMC ground vehicles, and aircraft) and be in a wavelength regime that is considered “eye-safer” when considering issues of defuse reflection or scatter when nearby observers are present. Gimbal and optics development or advancements in the shortwave infrared regimes may be offered but are not the primary technical objective in consideration for this topic.
Recent advances in laser sources [Ref 1] with high beam quality at the 2 micron wavelength, using Holmium and Thulium doped fiber optic-based power gain amplifiers, have shown a potential pathways for innovation to reach higher average powers (in Continuous Wave operation) in the multi-kilowatt regime, within the 2.0 to 2.4 micron (µm) band and falling within an atmospheric spectral short-wave infrared (SWIR) transmission band due to their low absorption of light by atmospheric water vapor. A pulsed system with a pulse gated optical imaging sensor offers the unique opportunity to not only provide a simple Laser Detection and Ranging (LIDAR) capability but also provide doppler-based discrimination information on the imaged objects – which could exceed systems’ capabilities typical from the 1.0-1.6 micron near infrared (NIR) band. The marine wave boundary layer (MWBL) can have higher scattering properties when comparing NIR to the selected SWIR bands, and is considered less detectable using widely available commercial, uncooled sensors than standard visible to NIR based illumination systems. A system that can operate in either CW or coupled pulse modes with a time resolved, range gated sensor and with high resolution windowing is the primary objective of this topic.
The Navy and Department of War seeks a unified approach with a scalable prototype device for use in evaluation for Electro-magnetic (EM) Spectrum warfare with an objective of gaining military advantages and achieving freedom of action across missions in support of maritime, surface warfare. However, the one system should show an ability to handle two separate capabilities developed through scaling. The first is development of a small, compact, lightweight SWIR (2.0-2.4 wavelength) high energy laser illuminator and coupled range-gated imaging sensor, including necessary optics suitable for short range sensing from small (group I or II) unmanned aerial vehicles or drones. While shorter ranges are acceptable for these missions (tens to hundreds of meters), the need for higher power still exists to conduct object discrimination at longer range (kilometers) and collect as much information (e.g., doppler shifts) from sensors as is technically possible. These smaller devices may diverge because of the requirements of size, weight and power (SWaP) toward a lower power-ganged diode array of microbolometers that has sufficient optical gain sensitivity to achieve doppler data, at the sacrifice of higher resolution spatial data typically obtained from devices that are based on focal plane arrays. Hybrid approaches combining sensor types shall be considered. Imaged target objects are expected to be in centimeter to meter size, and either stationary or have relatively low velocities (meters per second).
At the other end of the scale, a desire exists for a larger, fixed placement optical device on a moving or mobile platform (i.e., ground, air or sea-based vehicle) that can accurately discriminate and range objects at significantly greater distances (hundreds of meters to tens of thousands of meters) and are larger (tens of meters in length) with higher velocities (from tens to hundreds of meters per second). These systems require significantly higher source power, larger optics and higher quality vibration control, longer photonic travel distance, shorter pulse lengths, and higher peak power; have longer latency of time from emission to reception; and include the optical distortions that occur during light travel, reflection, and return. These larger devices may favor a combination of both focal plane arrays with coupled microbolometers using highly resolution time coupled range gating techniques, and significant relaxation of SWaP and include potentials for active cooling. However, the complexities of field conditions where the systems are deployed can vary greatly, with humidity (0-100%), rain, fog, particulates, and temperature variation (-55°C to +125°C) are not negotiable for either class of system. The need for higher laser power may be approached by beam combining smaller sources, but simplicity is preferred with ruggedness to dynamic shocks required under this topic, at least initially.
This effort is driven by both new threats and available and emerging technologies that have the potential to vastly improve the agility and flexibility of the Navy systems by utilizing high-energy lasers for Battle Space Supremacy and Water Space Management as envisioned by the Chief of Naval Operations (CNO). The current technology for High Energy Laser (HEL) at this wavelength for kilowatt class amplifiers is in early development. A major challenge exists for this technology to be viable for development of doped fiber for the 2 µm kW class fiber amplified systems; however, other potential laser source types will be considered. Gaseous and chemical lasers are not considered to be acceptable for this solicitation. The Navy seeks to address the manufacturability, electrical-to-optical (EO) efficiency and conduct technology risk assessments and risk reduction of this class of solid-state laser amplifier design.
Work produced in Phase II may become classified. Note: The prospective contractor(s) must be U.S. owned and operated with no foreign influence as defined by 32 U.S.C. § 2004.20 et seq., National Industrial Security Program Executive Agent and Operating Manual, unless acceptable mitigating procedures can and have been implemented and approved by the Defense Counterintelligence and Security Agency (DCSA) formerly Defense Security Service (DSS). The selected contractor and/or subcontractor must be able to acquire and maintain a secret level facility and Personnel Security Clearances. This will allow contractor personnel to perform on advanced phases of this project as set forth by DCSA and ONR in order to gain access to classified information pertaining to the national defense of the United States and its allies; this will be an inherent requirement. The selected company will be required to safeguard classified material during the advanced phases of this contract IAW the National Industrial Security Program Operating Manual (NISPOM), which can be found at Title 32, Part 2004.20 of the Code of Federal Regulations.
