N13A-T023 TITLE: Solid-State Fundamental Mode Green Laser for Ocean Mine Detection

TECHNOLOGY AREAS: Sensors, Electronics, Battlespace

ACQUISITION PROGRAM: COBRA Blocks II & III, ALMDS, RAMICS, AQS-20, SHD-FY12-04 (FNC)

OBJECTIVE: The objective is to develop and demonstrate a solid-state laser with the primary fundamental lasing output in the wavelength range of 470-540 nanometers. This would greatly enhance laser output efficiency. The selected frequency range enables the penetration of water which is required for airborne and underwater sensors being developed to detect mines in the ocean environment.

DESCRIPTION: The sensors under development for mine hunting are designed to be payloads on small tactical unmanned vehicles (TUAV) or manned platforms with limited space and power. Therefore size, weight, and power (SWaP) consumption are critical considerations. The solid-state lasers currently available achieve the desired "green" output wavelength by using an approach called "frequency doubling" which results in a conversion loss of about 50% leaving most systems with wall plug efficiencies of only 3 to 5%. The use of a solid-state laser with the primary fundamental lasing output in the desired wavelength (470-540 nanometers) should enhance laser output efficiency by avoiding these losses. The laser system could be smaller, lighter, consume less power, and have reduced heat load handling requirements.

PHASE I: Define and develop a concept for a pulsed laser capable of achieving a fundamental output in the wavelength range of 470-540 nanometers. The technology must be scalable to operate at power levels in the order of 50 Watts with repetition rates of 30-400 Hertz. The concept should require minimal thermal conditioning and minimize the use of components requiring high-precision temperature control.

PHASE II: Produce prototype hardware based on the Phase I work to demonstrate and validate a pulsed laser capable of achieving a fundamental output in the wavelength range of 470-540 nanometers under test conditions of at least 1 Watt of output power. An in-depth analysis should demonstrate how higher output power levels would be accomplished and the impact on size, weight, and power consumption.

PHASE III: The successful design, development, and demonstration of a solid-state laser having the primary optical output in the specified wavelength has strong potential to be flight tested in SHD-FY12-04 before transitioning into the COBRA (Block II / Block III), ALMDS, and AQS-20 programs of record. A SECRET clearance may be required for Phase III.

PRIVATE SECTOR COMMERCIAL POTENTIAL/DUAL-USE APPLICATIONS: SHOALS system used to map bathymetry, and any other systems that penetrate water.

REFERENCES:
1. ALMDS Laser System, Proc. SPIE 4968, 163 (2003); Kushina, Heberle, Hope, Hall (Cutting Edge Optronics, Inc.); Calmes (Arete)

2. High-Power heat-insensitive resonator for a diode-side-pumped ND:Y3AL5O12 on high-gray-tracking-resistivity KTiOPO4 solid-state green laser. Opt. Eng 47, 084201 (Aug 06, 2008); Xiu Li, Xiu-yan Chen, Hao-wei Chen, Yao Hou, Si-yuan Wang, Zhao-yu Ren, and Jin-tao Bai