DOUBLE PASS DOUBLE ETALON SPECTROMETER

摘要

PROBLEM TO BE SOLVED: To provide an ETALON-based spectrometer. SOLUTION: In a preferred embodiment of a first double pass ETALON-based spectrometer, a second ETALON suitable to a first double pass ETALON is used to generated an extremely precise fringe data. The spectral component of a diffused beam is angularly separated when transmitted through the ETALON. A retro reflector reflects and returns the transmitted component through the ETALON. The spectral component transmitted twice is advanced through the second ETALON and converged onto a light detector that is a photodiode array in a second preferred embodiment. The spectrometer can generate the extremely precise fringe data with an extremely compact size and allows a band width measurement accompanied by a precision necessary for microlithography for bothΔλFWTH andΔλ95.