Direct measurement of the transmission spectrum of an intracavity electro-optic birefringent filter using cavity ringdown spectroscopy

Birefringent filters are often used in laser resonators to obtain narrowband operation [1]. However, the intracavity birefringent filter has never been characterized directly. Cavity ringdown spectroscopy (CRDS) [2] is an ideal technique to measure the effective insertion loss spectrum of such a filter.