N093-164 TITLE: Optical Aperture Gating for Single-pixel and Imaging LIDAR Systems

TECHNOLOGY AREAS: Sensors

ACQUISITION PROGRAM: PMA-264, Air Anti-Submarine Warfare Systems; ACAT IV

The technology within this topic is restricted under the International Traffic in Arms Regulation (ITAR), which controls the export and import of defense-related material and services. Offerors must disclose any proposed use of foreign nationals, their country of origin, and what tasks each would accomplish in the statement of work in accordance with section 3.5.b.(7) of the solicitation.

OBJECTIVE: Develop new innovative materials and a novel all-optical and fast gating technique that would improve daytime performance of photocathode type lidar detectors for aperture sizes approaching one square cm and larger.

DESCRIPTION: Innovative technology is sought that would provide photocathode protection for expensive, high-sensitivity detectors such as photomultipliers (PMTs) and intensified photodiodes (IPDs). Novel solutions should provide the capability of a superior gating technique for these detectors which are used in lidar systems and imaging systems. Current techniques are limited to electrical gating, such as dynode gating within PMTs, which mixes gate pulses with data signals causing signal distortion. Currently available electro- and acousto-optic techniques are not applicable as they require highly polarized and nearly collimated optical source to gate quickly and effectively.

Proposed solutions should take the following technical design goals into consideration. The proposed technique should require only minor design variations to work at specific wavelengths (e.g. at 480nm or 532nm) within the blue green spectrum (i.e. 450nm to 550nm). Strong out-of-band blocking should be included. The gate-off to gate-on contrast should approach -30dB. The loss for the gate-on condition should be minimal (e.g. < 2dB). The technique should work with unpolarized light with ensemble incident angles from collimated to at least +/- 10 degrees (+/-40 degrees desirable). Single-pixel lidars need gate-off to gate-on transition times of 100 nanoseconds or faster, while gate-on to gate-off transition times of a few hundred nanoseconds are reasonable. Gate-on state duration times of one to a few microseconds is useful. Imaging lidar applications need off�on and on-off transition times of 10 nanoseconds or faster with a gate-on duration of 10s of nanoseconds. The gate repetition frequency should be at least 1 KHz and be capable of synchronizing, with very low jitter, to an external trigger.

Techniques such as, but not limited to, holography and dynamic-holography, exploiting electro-optic refractive effects and photo-refractive effects are appropriate. Conceivably the solution would be in the form of one or a few optics that could be integrated into the middle or back end of a standard telescope design (e.g. refractive, reflective). Control signals (e.g. trigger timing) and power would be externally applied. The technique would perform optical gating of the light input to a detector at the back end of a telescope. The baseline design should operate with a gated aperture size approaching 1 square centimeter or larger.

PHASE I: Demonstrate feasibility of proposed approach. Generate ray-trace design diagrams showing component locations within a simple telescope design. Demonstrate proof-of-concept with consideration to scaling to larger aperture sizes, cost and availability of required materials and services. Perform preliminary bench-top testing to verify performance of potential designs.

PHASE II: Develop and demonstrate a working bench-top design at 532nm and develop and deliver a fully functioning prototype with a 1 square cm aperture. Generate a complete design for operation at 480nm. It is anticipated that small companies will seek a commercialization partner capable of manufacturing larger aperture versions.

PHASE III: Complete prototype development and document the design. Transition the technology to air and underwater remote sensing applications.

PRIVATE SECTOR COMMERCIAL POTENTIAL/DUAL-USE APPLICATIONS: Commercial applications that would benefit from an all optical gating technique include all optical sensor systems such as single-pixel and imaging LIDAR Systems for DOD and civilian uses for land-based, airborne and satellite applications. Benefiting applications include air and underwater remote sensing and airborne mapping.

REFERENCES:
1. Photomultiplier Tubes - Principles and Applications, Philips Photonics, sect. 3.1.5 Exposure, p3-6, 1994.

2. Photomultiplier Tubes - Basics and Applications 3rd Edition, Hamamatsu Corp., Chapter 10 MCP-PMTs, Sect 10.2.4 Saturation Effects, P211, 2006.

KEYWORDS: Lidar; Electro-refractive; Photo-refractive; Dynamic-holography; Photomultiplier; Photocathode

** TOPIC AUTHOR (TPOC) **

DoD Notice:   Between July 27 through August 23, 2009, you may talk directly with the Topic Authors 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 August 24, 2009, 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 (09.3 Q&A) during the solicitation period for questions and answers, and other significant information, relevant to the SBIR 09.3 topic under which they are proposing.

If you have general questions about DoD SBIR program, please contact the DoD SBIR Help Desk at (866) 724-7457 or email weblink.