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January 5,2016

A16-083 Laser Protection for Day Cameras

  • Release Date:12-11-2015
  • Open Date:01-11-2016
  • Due Date:02-17-2016
  • Close Date:02-17-2016

DESCRIPTION: The proliferation of multiple laser wavelengths may present a significant danger to ground vehicle vision systems, including day camera sensors. One way to protect viewing systems against fixed frequency lasers is to use narrow band spectral line rejection filters at the known laser wavelengths, attenuating incident laser energy at these wavelengths, thus preventing laser radiation from damaging the sensor. As the number of possible laser wavelengths increases, this approach becomes less practical. Another approach relies on nonlinear optical materials (nonlinear absorbing dyes, nonlinear scattering suspensions, etc.) which must be located at the focus of an optical system in order to obtain the high fluence necessary to trigger the nonlinear mechanism. This SBIR topic solicits new, innovative approaches to provide protection against pulsed lasers operating at wavelengths throughout the visible spectrum for day camera sensors. The protection material within the protection system shall be a stable solid material and no powered electro-optics are allowed within the protection system. The protection material/system can be integrated in any location within the optical system. However, techniques for integration of the protection technology into optical systems which limit the growth of the optical system space claim and minimize integration cost are preferred. The proposed technology should allow ample transmission of ambient visible light and be of high optical quality (including low haze) so as not to significantly degrade vision system performance. It should have a fast response time when exposed to dangerous fluence levels, sufficient to react to and block incident laser pulses to a high optical density. The technology must have a broadband response; blocking any visible wavelength (i.e. 400-700 nanometers) which has sufficient irradiance to damage sensors significantly. The concept should be capable of changing from a high transmission state to a very low transmission state within sufficiently short time to block nearly all of the light contained in a light pulse emitted from a (non Q-switched or Q-switched) pulsed laser. The dynamic range (the range between the minimum and maximum input pulse energies over which the protection is provided) shall span several orders of magnitude. Protection from multiple pulses at commercially available repetition rates is desired. The laser-induced damage threshold of the protection material or system components and the localized laser damage site's impact on sensor performance shall be discussed. The proposal should discuss in detail the spectral transmittance in the transmissive and attenuating states, the activation threshold, the response time, the optical density in the attenuating state, and the recovery time of the technology, as well as any other important technical details. If at all possible, the proposal should show preliminary optical limiting data taken in an optical system with the material at an f/5 intermediate focal plane.
 

PHASE I: Develop a laser protection concept designed to meet the requirements stated. Identify critical technologies for realizing this concept. Conduct theoretical analysis and limited laboratory testing (including optical limiting performance testing and optical characterization testing) on sample materials or devices to prove the feasibility of the concept. Phase I deliverables shall be test data, monthly progress reports, a final technical report, a final review meeting (including presentation materials) and sample materials or devices.
 

PHASE II: Develop and demonstrate a laser protected prototype system. The prototype should be built in the form, fit and function of, or integrated for use in conjunction with, a camera system to be proposed by the contractor during Phase I and approved by the government. This prototype shall be tested for laser protection performance and degradation to optical system performance in a laboratory environment. Factors to be considered include, but are not limited to, optical density upon laser illumination, response time, recovery time, linear optical properties under normal daylight illumination, ease of manufacture, and environmental stability. Optical density and response time upon laser illumination should be sufficient to protect the sensor from common class IV visible pulsed lasers. The recovery time should be on the order of a frame of video, commonly 1/30th or 1/60th of a second. The linear optical transmission properties under normal daylight should be higher than 40%. The proposed technology should be stable over military operating environmental conditions as specified in Mil-STD-810 E, specifically the operation and storage temperature requirements. The method of manufacture should be described. Phase II deliverables shall include a prototype laser protected camera system, interim sample materials (if applicable), test data, monthly progress reports, semi-annual progress reviews, a final review, a final report, and a Phase II project summary.
 

PHASE III DUAL USE APPLICATIONS: The most likely Phase III transition path is integration of this technology into ground combat vehicles via vehicle system prime contractors.

PRIVATE SECTOR COMMERCIAL POTENTIAL: This technology could be applied to other military platforms
 

REFERENCES:

1. Standards for Hardening U.S. Army Sensors Against Antisensor Lasers, 27 April 2008.
 

2. Filter, Laser Hazard Protection, MIL-DTL-62422D(AT), 17 Aug 2010.
 

3. American National Standard for Safe Use of Lasers, ANSI Z136.1—2014, American National Standards Institute, Inc., 2014.
 

4. Spiricon Corporation, Camera Selection Guide, Spiricon Inc., Logan Utah, 84341-5740, 2003.
 

5. Zhang, C., Blarre, L., Walser, R.M., and Becker, M.F., “Mechanisms for laser-induced functional damage to silicon charge-coupled imaging sensors,” Applied Optics, Vol. 32, No. 27, Sep 1993.
 

6. Teppo, E., “GE TN2505 CID Array Camera Characteristics as a Function of Incident Laser Fluence at 532 nm and 1064 nm,” Big Sky Corporation, P.O. Box 3220, Boseman, MT 59772 May 1986.
 

7. Lu, J., Ni, X., Lin, Z., and He, A., “Measurement of threshold of damage to a charge-couple device caused by a Q-switched laser,” Microwave and Optical technology Letters, Vol., 11, No. 4, March 1996.
 

8. Janesick, J., Scientific Charge-Couple Devices, SPIE Press, P.O. Box 10 Bellingham, Washington, 98227, 2000.