N141-008 TITLE: Power scaling of blue lasers with high peak-power and repetition rate for detection of underwater objects

TECHNOLOGY AREAS: Sensors

ACQUISITION PROGRAM: PMA 264

OBJECTIVE: Develop a scalable high peak-power laser solution consisting of either a single laser or multiple beam-combined blue lasers for use as a transmitter source for detection of underwater objects from an aircraft.

DESCRIPTION: There is a need for a high peak-power blue laser system solution to be operated in pulsed mode with high repetition rate for detection of underwater objects from an aircraft at an altitude of not more than 1000 ft. It should be rugged, compact, and light enough to be used in Naval aircraft, both fixed and rotary wing platforms. The current State Of the Art (SOA) which includes Optical Para-Metric Oscillators (OPOs), wave length doubling of titanium sapphire (TiSa) based lasers, doubling and tripling of other laser hosts, and blue laser diodes, do not currently support the performance, size and weight objectives needed. Many commercially available lasers and near term developmental lasers meet a few of the required characteristics but none can meet every performance criteria. It is paramount that the blue laser solution meets or exceeds the design objectives in order to be effective for detection of undersea objects. Blue laser is required due to the ability of the blue wavelength to penetrate the ocean to significant depths compared to all other wavelengths. It is therefore the goal of this program to seek the development of a power scalable blue laser system solution that will meet the size, weight, performance and reliability requirements below while considering component costs for future production of the system. The proposer should consider this development as the innovative advancement and combination of blue laser and supporting technologies towards the goals stated below rather than a new effort to discover as yet unknown or untested blue laser concepts.

The performance objectives of the laser solution are:
1. High repetition rate (Threshold: 1 kilo hertz)
2. High peak power (Threshold: 10W average, Objective: 15W average; Threshold: 10 milli-joule, Objective:15milli-joules per pulse with pulse width no more than 20 nanoseconds)
3. Blue wavelength (Ideal wavelength is to match a Fraunhofer line in the blue (460 - 490 nano meters) but a laser with suitable power and repetition rate in that range would be acceptable
4. Line width of less than or equal to 0.1 nano-meter
5. Wall plug efficiency of greater than 5%
6. Laser beam quality M-squared less than 3.
7. Light weight. (Total weight including the laser head, cooling system, power supply, and control system) Threshold: less than 100 pounds, Objective: less than 60 pounds.
8. Small volume. (Total volume for the cooling system, power supply, control system and laser head) Threshold: less than 3 cubic feet, Objective: less than 2 cubic feet.
9. Ability to be ruggedized and packaged to withstand the shock, vibration, pressure, temperature, humidity, electrical power conditions, etc. encountered in a system built for airborne use.
10. Reliability: Mean time between equipment failure�300 operating hours.
11. Full Rate Production Cost: Threshold < $50,000; Objective <$15,000 (based on 1000 units)

Because of Size, Weight and Power (SWaP), ruggedization requirements and restricted use of hazardous material in airborne applications, argon ion lasers, chemical lasers, and dye lasers are unacceptable. Furthermore, systems using cryogenic cooling will also be discounted.

PHASE I: Determine and design a viable and robust laser system solution consisting of either a single laser or multiple beam-combined blue lasers which meets or exceeds the requirements specified. Identify technological and reliability challenges of the design approach, and propose viable risk mitigation strategies.

PHASE II: Design, fabricate, and deliver a laser system prototype based on the design from Phase I. Test and fully characterize the system prototype.

PHASE III: Finalize the design and fabricate a ruggedized laser system solution and assist to obtain certification for flight on a NAVAIR R&D aircraft.

PRIVATE SECTOR COMMERCIAL POTENTIAL/DUAL-USE APPLICATIONS: High power, pulsed lasers have applications in manufacturing and lithography. Oceanographic bathymetry systems for survey and exploration work would benefit greatly from this laser system solution.

REFERENCES:
1. Saleh, B.E.A. (1991). Fundamentals of Photonics. Wiley Interscience

2. Weber, M. (2001). Handbook of Lasers. CRC

KEYWORDS: Airborne; High Power; Asw; blue laser; high repetition rate; Oceanography

** TOPIC AUTHOR (TPOC) **

DoD Notice:   Between November 20 and December 19 you may talk directly with the Topic Authors (TPOC) to ask technical questions about the topics. Their contact information is listed above. For reasons of competitive fairness, direct communication between proposers and topic authors is not allowed starting Dec 20, 2013, when DoD begins accepting proposals for this solicitation.

However, proposers may still submit written questions about solicitation topics through the DoD's SBIR/STTR Interactive Topic Information System (SITIS), in which the questioner and respondent remain anonymous and all questions and answers are posted electronically for general viewing until the solicitation closes. All proposers are advised to monitor SITIS (14.1 Q&A) during the solicitation period for questions and answers, and other significant information, relevant to the SBIR 14.1 topic under which they are proposing.

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