We show that a crystalline LiNbO<sub>3</sub> grism and a hybrid grism made of a LiNbO<sub>3</sub> transmission grating and a ZnS prism can be new and powerful dispersing elements with refractive indices high enough to realize high spectral resolution for visible to near-infrared astronomical spectrographs with transmission optics. We describe the basic principle and the limitation to minimizing the spectral separation that is due to the inherent birefringence of such an optically anisotropic crystal used for grisms.
© 1998 Optical Society of America
Noboru Ebizuka, Masanori Iye, and Toshiyuki Sasaki, "Optically Anisotropic Crystalline Grisms for Astronomical Spectrographs," Appl. Opt. 37, 1236-1242 (1998)