Laser Hardening of Submarine Optical Systems

The objective of the proposed work is study of opportunities of laser hardening of submarine optical systems that include visible and variety of infrared cameras as well as sensors and optics incorporated in the high energy beam controller system. The phase 1 work and the Phase 1 Option will allow identifying laser hardening system requirements that are specific to submarines, including requirements to optical and nonlinear optical properties of the materials to be used in the system. The Phase 1 work and its Option would also allow to develop and analyze the main concepts for laser hardening which will be tested and prototyped in the Phase 2 of the project. 4G Optics is most promising to provide effective solutions to the problem of laser hardening, particularly, for submarine optical systems, due to the opportunity of performing any optical function (lens, prism, beam shaping, etc.), even combinations of optical functions, with micrometer thin transparent material layers. Thus, laser hardening systems can complement optical systems of photonics masts and high energy laser beam controllers of future submarines without major modifications to the present opto-mechanical layouts within the masts. Notably, 4G Optics allows controlling laser beams with practically 100% efficiency. By that, its properties are inherently different for light propagating in opposite directions. For example, the sign of the focal length of a 4G lens is positive or negative depending on which side of the lens is facing the beam. Finally, 4G optical components can be made using highly nonlinear optical materials enabling optically switching of 4G optical components and systems between diffractive and non-diffractive states. The main challenge of laser hardening technologies is to provide protection against all different wavelengths and types of laser beams, pulsed and cw, ensuring sufficiently fast reaction times, and high enough contrast in rejecting the threat laser beams.  Additionally, this has to be accomplished without appreciably affecting the functions of the variety of optical sensors and systems. Additionally, when incorporating diffractive optics into a system, the challenge is overcoming dispersive and polarization effects which we expect to accomplish using combinations of 4G optical films that provide polarization-independent compensation of diffraction effects.