Current frequency-agile technologies for laser eye and sensor protection rely on nonlinear optical effects. However, the nonlinear optical materials must be located at the focus of optical system for high fluences necessary to activate the effective protection mechanism. The use of focusing optics leads to many practical limitations in system performance, size, weight, architecture and cost. Also, most nonlinear materials do not have broad spectral response against the frequency agility of laser threats. Based on our preliminary study, we proposes herein a novel Non-Focal-Plane Optical Power Limiter (NFP-OPL) for protecting eyes and sensors against lasers throughout the visible spectrum with improving normal transmission, time response and limiting performance. The operation mechanism of NFP-OPL is based on sensitive nano-scale molecular switching processes, rather than electronic transitions of higher energy levels. Thus, large nonlinear optical effect with high optical sensitivity can be obtained without using any focusing optics. The proposed device will be polarization-independent and thin-film-like with high optical quality, allowing ample transmission of ambient visible light. Phase I will demonstrate feasibility of NFP-OPL. The performance will be optimized in Phase II to yield a practical functional, rugged prototype with improved system performance and cost reduction to support military and commercial applications.
Keywords: Laser Protection, Power Limiting, Nonfocal Plane, Broadband, Photo-Isomerization.
