| 摘要 |
A double pass etalon based spectrometer. Spectral components of a diffused beam are angularly separated as they are transmitted through an etalon. A retroreflector reflects the transmitted components back through the etalon. Twice transmitted spectral components are focused onto a light detector which in a preferred embodiment is a photo diode array. The spectrometer is very compact producing precise fringe data permitting bandwidth measurements with precision needed for microlithography for both DELTA lambda FWHM and DELTA lambda 95%. <IMAGE> |
