HOLOGRAPHIC INTERFEROMETER FOR OPTICAL MEASUREMENT

MULTISPECTRUM GUIDANCE SYSTEMS ARE BEING DEVELOPED WHICH CONTAIN EXTREMELY SMALL, NON-SPHERICAL OPTICAL COMPONENTS FOR LONG WAVELENGTH IR SEEKERS. THE NAVY REQUIRES A NONCONTACT METHOD OF TESTING THESE PARTS FOR CONFORMANCE TO SPECIFICATIONS PRIOR TO THEIR ASSEMBLY INTO THE SYSTEM. APA OPTICS PROPOSES TO DEVELOP AN OPTICAL INTERFEROMETER WHICH WILL USE LOW COST COMPUTER GENERATED HOLOGRAMS (CGH) AS NULL LENSES. AN ALTERNATIVE APPROACH IS THE LASER STYLUS PROFILOMETER WHICH USES A FOCUSED LASER BEAM TO LABORIOUSLY SAMPLE A TEST SURFACE MOUNTED ON A 3-AXIS TRANSLATION STAGE. BY COMPARISON, AN OPTICAL INTERFEROMETER OFFERS THE ADVANTAGES OF RAPID, FULL APERTURE TESTING OF NOMINALLY IDENTICAL PARTS FOLLOWING AN INITIAL SETUP. MOREOVER, THE OPTICAL INTERFEROMETER CAN BE CONFIGURED TO DIRECTLY MEASURE OPTICAL PERFORMANCE, WHEREAS AN OPTICAL PROFILOMETER CAN ONLY MEASURE SURFACE ACCURACY. AFTER STUDYING THE TESTING REQUIREMENTS, APA OPTICS WILL DESIGN A HOLOGRAPHIC INTERFEROMETER TO MEET ALL REQUIREMENTS. THE APPARATUS WILL BE BUILT AND TESTED UNDER PHASE II.