DON26BZ01-NV012 — Optical Power Limiters Countering Frequency Agile Lasers and Dazzlers

Award Maximum: $140,000 (Base) / $100,000 (Option) Period of Performance: 6 months (Base) + 6 months (Option) Phase Type: Phase I

OBJECTIVE: Develop Mid-Wave Infrared/Long-Wave Infrared (MWIR/LWIR) nonlinear optical (NLO) dyes embedded in sol-gel glass operating as an Optical Power Limiter that protects optical sensors from damage caused by high-intensity light by reducing transmittance at high input power levels such as from frequency agile lasers and dazzlers.

DESCRIPTION: The proliferation of commercial, visible, and infrared wavelength laser systems is increasingly becoming a threat to our warfighters, which drives the need for further research and development for electro-optical/infrared (EO/IR) sensor. Current fielded sensor protection equipment is limited to fixed wavelength filters. However, broad band filters that are designed to circumvent multiwavelength laser threats are plagued by low transmittance, which degrades the sensitivity and performance of the sensor. Future warfighter threats include frequency agile lasers and dazzlers which have the potential of defeating fixed filters. Self-activating (passive) devices, where protection is activated by the incoming radiation (optical limiters), are the best approach to counter frequency agile and short pulse laser threats.

This SBIR topic solicits new, innovative NLO dyes embedded in sol-gel glass to provide sensor protection from frequency-agile laser and dazzlers operating in the MWIR/LWIR spectrum.

The NLO dyes embedded in sol-gel glass critical requirements are: (1) Wavelengths – threshold MWIR 3 to 5 micron goal MWIR/LWIR 3 to 12 microns; (2) Response time: < 1ns; (3) Recovery time: < 1ms; (4) Low-intensity transparency is > 50%; (5) For light intensity or fluence above the limiting threshold (LT), the attenuation is > 20dB; (6) The Damage threshold (DT) is at least 10 times larger than that of the nonlinear optical material used; (7) The fluence limiting threshold (LT) is below 500 milli-joules/cm^2/pulse; (8) Multiple use without performance degradation exceeds 10,000 pulses; (9) Wide acceptance and protection angles; (10) Testing should be performed using f-number optics no greater than f/10; (11) Dynamic range (~120 dB); (12) Rapid response time (~20 us); (13) Optical limiting threshold of 6.5 W/cm2 at room temperature.

Work produced in Phase II may become classified.

PHASE I: Develop a NLO dye embedded in sol-gel glass protection concept designed to meet the critical requirements stated. Identify critical fabrication processes for realizing this concept. Conduct theoretical analysis and limited laboratory laser irradiation experiments on sample materials or devices to prove the feasibility of the concept. Demonstrate a clear ability to prepare at least 1 inch diameter optically clear sol gel glass boules that are suitable for cutting and polishing. The Phase I deliverables will also include prototype plans to be developed in Phase II, 3-dimensional model, Weight Budget, Trade-off analysis, and preliminary lab test data and supporting analysis.

PHASE II: Develop and demonstrate a NLO dye embedded in sol-gel glass protection prototype system. Prototype optical limiting for mid-infrared transparent windows should be built in the form, fit and function of, or integrated for use in conjunction with, common Embedded Image Periscopes (EIPs) or embedded vision blocks on ground combat vehicles. This NLO dye embedded in sol-gel glass prototype shall be jamming, damage, and device tested for critical requirements listed in the Topic Description, broadband laser protection performance, linear absorption, and degradation to optical system performance in a laboratory environment. It is probable that the work under this effort will be classified under Phase II.

PHASE III DUAL USE APPLICATIONS: Pursue commercialization of the various technologies developed in Phase II for transitioning expanded mission capability to a broad range of potential government and civilian users and alternate mission applications. Commercial applications could include coatings on car windows to attenuate incoming headlights, and coatings on windows of buildings to reduce heating from the sun. This system could be applied to other military platforms as well as the commercial and private airline industries as a defense against real world terrorist threats.

KEYWORDS: Sol-Gel Glasses; Laser protection; Frequency-agile laser; Dazzlers; Mid-Wave Infrared; Long-Wave Infrared