The present invention is an adaptive laser protection device which adaptively forms a reflection holographic optical element to reflect away incident laser radiation. The laser protection device includes a layer of a nonlinear optical material which has an index of refraction varying with light intensity, a transparent layer having a depth greater than the coherence length of the expected ambient illumination and less than the coherence length of the expected laser radiation, and a partially reflecting layer on the far surface of the transparent layer. Laser radiation incident on the laser protection device forms an interference pattern in the nonlinear optical material between directly incident light and light reflected from the partially reflecting layer. This interference pattern within the nonlinear optical material causes the formation of a holographic optical element due to varying indices of refractions. The geometry of the holographic optical element substantially reflects away the incident laser radiation protecting the user. The preferred embodiment includes a transparent substitute for supporting the device and an optical filter to limit incident light to a predetermined band.
This invention relates to an active Laser Protection System (LPS) system specifically designed to provide a device that automatically adjusts a protection panel of the device in response to laser light exposure thus preventing a user from being exposed to damaging laser light. In one embodiment the LPS system utilizes a light weight portable goggle type eyewear. In yet another embodiment the LPS system is comprised of contact lenses worn by the user. The LPS system may be used in all light transmissive surfaces where the penetration of laser light is not desired, such as aircraft, spacecraft, vessel, train, and automotive windshields, etc. The LPS system may also be utilized as a replacement window for structures where laser light penetration is undesired. The protection panels utilize Liquid Crystal Displays (LCD) that are activated by laser sensors by means of a microprocessor and power supply means. The device also automatically replaces non-laser visible light that may be blocked because the light was of the same wavelength as the blocked light by projecting that light by means of activating the LCD accordingly by means of the microprocessor.
A lens includes a medium which absorbs laser radiation that may be harmful to the eye or other high gain optics, raising its temperature and thereby changing its index of refraction, which causes a phase change in the radiation passing therethrough. The medium may be periodically bounded by thermal sinks, thereby providing a periodic differential in temperature rise, may be provided in a length which varies periodically or may have a density of absorbing material which varies periodically, thereby to have a periodic absorption characteristic. The periodicity, which may be regular or random, provides a periodic variation in total phase change, which causes interference (thermal blooming) that disperses the radiation sufficiently to lower the intensity at the retinal spot below that which would cause damage. Eyeglasses with mutually perpendicular periodicity provide degraded vision of useful images while being protected from harmful radiation.
A stowable laser eye protection system is provided as a solution for protecting the eyes of pilots and other vehicle operators and optical sensors such as during critical phases of flight and for general protection against a wide range of spectral wavelengths. A stowable laser eye protection system provides protection that can be manually or automatically extended and retracted. For example, by installing flexible laser protective films on rollers at each window of an aircraft cockpit, the protection can be put in place during taxi before take-off and stowed when the aircraft is a safe distance away from a potential threat area such as after reaching a particular altitude. A similar activity could be used for approach and landing, where the protection is extracted when the aircraft approaches a threat condition or critical phase of flight and retracted after landing.
A method of fabricating a diffractive optical element includes the steps of: etching a negative of a desired multi-level diffraction pattern onto a molding surface of a quartz master element using photolithography, assembling the master element as a portion of a mold, and injecting a plastic molding composition into the mold and against the molding surface of the master element to injection mold a diffractive optical element, whereby the optical element has the desired diffraction pattern on its surface. The diffraction pattern is preferably formed on the quartz master using VLSI photolithography.
A method of fabricating a diffractive optical element includes the steps of: etching a negative of a desired multi-level diffraction pattern onto a molding surface of a quartz master element using photolithography, assembling the master element as a portion of a mold,and injecting a plastic molding composition into the mold and against the molding surface of the master element to injection mold a diffractive optical element whereby the optical element has the desired diffraction pattern on its surface. The diffraction pattern is preferably formed on the quartz master using VLSI photolithography.