FABRICATION OF A VERSATILE HOLOGRAPHIC OPTICAL ELEMENT FOR HIGH RESOLUTION SPECTROSCOPY

FABRY-PEROT INTERFEROMETERS ARE ROUTINELY USED IN STUDYING UPPER ATMOSPHERIC WIND VELOCITIES, TEMPERATURE DIFFERENCES, AND TO MONITOR WEAK EMISSIONS FROM ASTRONOMICALOBJECTS. FOR A GIVEN WAVELENGTH, ETALON PLATE SPACING AND INDEX OF REFRACTION OF MEDIUM BETWEEN THE PLATES, THE OUTPUTIS AN INTERFERENCE PATTERN OF CONCENTRIC RINGS. THE CONVENTIONAL METHOD UTILIZES ONLY THE CENTRAL PORTION OF THEAIRY-DISC PATTERN. THEORETICALLY EACH RING CARRIES SAME LIGHT INTENSITY, THEREFORE IT IS OBVIOUS THAT THE THROUGHPUTOF THE SYSTEM WILL INCREASE DRAMATICALLY IF ONE UTILIZES MANY NUMBER OF RINGS. CONVENTIONAL WAY OF USING MULTIPLE ANNULAR APERTURES OR MULTIPLE DETECTORS AND THICK FOCUSING LENS DO NOT OFFER ANY EXTRA BENEFITS. A HOLOGRAPHIC OPTICAL ELEMENT IS PROPOSED TO REPLACE THE LENS, APERTURE AND FILTER IN A FABRY-PEROT INTERFEROMETER. THE PROPOSED HOE IS EXPECTED TO ENHANCE THE PERFORMANCE OF F-P SPECTROMETER DRAMTICALLY.