The design of a tunable Fabry–Perot étalon-based filter that has a passband of 0.01 nm and a free spectral band larger than 50 nm when operated in the center of the visible spectrum is described. The filter consists of two Y-cut lithium niobate étalons having thicknesses in a vernier ratio. The polarization state of light passing through the tandem étalons is rotated 90° before again being transmitted through the étalon pair. If the components are arranged in a symmetrical manner, the filter will operate with unpolarized incident light. Each étalon in double pass will have a greater transmittance than two individual étalons of the same average optical thicknesses, since variations in the physical thickness due to fabrication errors are correlated.
© 1997 Optical Society of America
[Optical Society of America ]
R. P. Netterfield, C. H. Freund, J. A. Seckold, and C. J. Walsh, "Design of a lithium niobate Fabry-Perot étalon-based spectrometer," Appl. Opt. 36, 4556-4561 (1997)