A quartz birefringent filter insensitive to incident angle

The shifting direction of a central wavelength for a quartz birefringent filter is found different when the filter is rotated around the axis parallel and perpendicular to the quartz optical axis in this paper. Based on this result, a new type of two-stage modified-Lyot quartz filter is presented, which shows that the central wavelength of this new type filter is actually insensitive to incident angle through theory analysis. Moreover, this conclusion is in good agreement with the relative experiment results.