Abstract: Apparatus is disclosed for protecting delicate sensor optics from the damaging effects of unwanted powerful laser radiation. A thin-film reflective pellicle 14 is placed in the light path of a sensor telescope. Incident light 10 is focused by some combination of optical elements 12 onto the reflective surface 28 of the laser hazard protector 14. The reflected light 10 is then imaged by further optics 16 onto a detector array 18. Should a signal too strong for the detector enter the sensor aperture with the incident light 10, the focused power at the surface of the pellicle 28 will ablate the carbon and metallic film, burning a hole in the pellicle, and the high-power light 11 will be deflected from the detector array and be absorbed instead by the beam dump 20. A power meter within the beam dump determines when the laser threat has stopped and signals the turning mechanisms 15a and 15b to turn the pellicle reflector to a fresh position at which point normal sensor operations may resume.

Abstract: Disclosed herein is a solar converter structure and fabrication process therefor which includes a composite zinc selenide fluorescent wavelength shifter (FWS) prepared with anti-reflective (AR) coatings on both major surfaces thereof. One of these AR coatings is adhesively bonded to an AR coating on the sunlight-receiving surface of a gallium arsenide or an aluminum gallium arsenide photovoltaic (PV) solar cell, and the "free-standing" FWS composite wavelength shifter protects the solar cell from proton and ultraviolet radiation damage. The ZnSe wavelength shifter has a spectral response below about 0.47 micrometers and the solar cell has a spectral response above about 0.47 micrometers. The wavelength shifter absorbs radiation in the 0.3 to 0.47 micrometer range and re-emits radiation to the solar cell in a band centered about 0.62 micrometers and well within the pn junction response spectra for the solar cell to thereby enhance its power output.

Abstract: A gallium arsenide solar cell is disclosed having an aluminum gallium arsenide window layer in which fine metallic contact lines extend through the aluminum gallium arsenide window to electrically contact the emitter layer, and a plurality of metallic grid lines disposed on the window layer cross the contact lines, thereby making electrical contact to the metallic contact lines. A flat metallic strip extending along one of the edges of the solar cell electrically couples the grid lines to one another. Consequently, two separate metals can be used, one with good ohmic contact properties for the grid lines and another with good adhesion and current conducting properties for the current collecting bars. Additionally, the metallic contacts lines can be made very narrow to reduce the contact area to the emitter thereby reducing the recombination current in the emitter.

Abstract: The quality of photovoltaic semiconductor material for use in solar cells may be determined through the determination of the minority carrier diffusion length, in a simple manner. First, a thick slug or a thin plate or slice of the semiconductor material is polished on the front side, and mechanically finished in a predetermined manner on the back side. Then light at two different wavelengths, is applied to the plate, and the photovoltage and light intensity is measured first with light of one wavelength incident thereon, and then with light of the other wavelength. The ratio of the two intensities required to give the same output photovoltage determines the minority carrier diffusion length. The apparatus includes a light chopper, a photocell or thermocouple for determining relative intensity, and a simple mounting cell, for non-destructively coupling to the semiconductor sample with sensing electrodes, on the opposite sides of the sample. The circuitry may include a digital voltmeter and a microprocessor.

Abstract: Disclosed herein is a solar converter structure and fabrication process therefor which includes a composite zinc selenide fluorescent wavelength shifter (FWS) prepared with anti-reflective (AR) coatings on both major surfaces thereof. One of these AR coatings is adhesively bonded to an AR coating on the sunlight-receiving surface of a gallium arsenide or an aluminum gallium arsenide photovoltaic (PV) solar cell, and the "free-standing" FWS composite wavelength shifter protects the solar cell from proton and ultraviolet radiation damage. The ZnSe wavelength shifter has a spectral response below about 0.47 micrometers and the solar cell has a spectral response above about 0.47 micrometers. The wavelength shifter absorbs radiation in the 0.3 to 0.47 micrometer range and re-emits radiation to the solar cell in a band centered about 0.62 micrometers and well within the pn junction response spectra for the solar cell to thereby enhance its power output.