Block defocused spherical fabry-perot interferometer

A solid Fabry-Perot interferometer with a quasi-confocal resonator has been constructed. The essential characteristics of this interferometer are discussed in relation to its advantages for spectral analysis. These advantages include high resolving power (>10(7)) with satisfactory instrumental finesse (>30) in static mode. Experimental results show that this instrument can be used for analysis of spatial coherence along the cross section of the incoming light beam.