SBIR-STTR Award

Reverse saturable absorbers (RSAs) are optically nonlinear materials that show increasingly high absorption at higher light intensities, and are thus excellent candidate materials for making optical limiters. However, the highest optical nonlinearities of the currently known RSAs are at least two orders of magnitude too low to be practically useful. The focus of our Phase I project is to use Jet Vapor Deposition (JVD), a novel, versatile, and powerful vapor deposition technology, to fabricate RSA thin films with significantly enhanced optical nonlinearity, exploring various photophysical, photochemical, and nonlinear optical mechanisms, Broadband optical limiting will be realized by combining a number of RSAs with enhanced nonlinearities in difference spectral regions into a single film. For practical applications, JVD optical limiting films may be directly applied to optical elements such as window and lenses, or optical instruments such as goggles and light sensors. JVD is a high rate, low cost, pollution-free process ready for high volume production on a commercial scale.

Intense laser pulses present a severe threat to military and civilian personnel as well as light sensors. This threat can be eliminated only by development of efficient optical limiters which transmit ambient light levels but block harmful intensities. Laser pulse levels of 100 millijoules can exceed the eye's damage level by a factor of 10(5), but known optical limiting materials have suppression factors of only 10(2). Indentification and synthesis of materials with required properties is difficult and no practical device yet exists. Our Phase II objective is to develop our proprietary Jet Vapor Deposition (tm) (JVD(tm)) process for large scale production of high efficiency Reverse Saturable Absorber (RSA) thin film materials and devices. We will use the JVD process to vapor deposit host-guest films with specially designed RSA chromophores as guests in robust inorganic hosts. The guests will be provided by our collaborators, Professor Seth Marder and Dr. Joseph Perry of CalTech/JPL, internationally known leaders in design, synthesis and characterization of novel NLO organic molecules. The JVD process enables enhancement of RSA response via local guest environment control such as heavy atom effects, host rigidity, host ionicity and graded concentrations. The JVD process provides advantages such as high rate, low cost, low temperature, pollution free processing. Anticipated success in Phase II will enable Phase III low cost manufacturing of RSA laser protective materials and devices.

Benefits:
A low cost method for thin film RSA optical limiting materials and devices for military and civilian application. Advanced understanding of organic guest NLO response in JVD process host-guest thin films.