An optical characterization method with high spectral resolution for broadband, multilayer dielectric gratings working at the −1st reflection order is demonstrated in this paper. The diffraction-efficiency measurement setup for the broadband gratings with high efficiencies mainly consists of a double-light-path system with a monochromator as the illumination source and an automatic rotation stage for incident and diffraction angles adjustment. Two typical practical difficulties, namely (1) the mismatch between the spot size of diffracted light and the limited detector aperture and (2) the shared propagation path between the incident and diffracted light at the Littrow angle, were well solved. A fabricated multilayer dielectric grating was measured on the established measurement setup. Diffraction efficiencies greater than 90% in the wavelength range from 763 to 852 nm were obtained with an average relative deviation less than 1.0%. At the moment, the wavelength resolution is 1 nm and the angle resolution is 0.2 deg. The high-resolution broadband diffraction spectrometry testing method is applicable to characterizing broadband pulse compression gratings in the laser systems.
© 2013 Optical Society of America
Diffraction and Gratings
Original Manuscript: August 17, 2012
Revised Manuscript: December 20, 2012
Manuscript Accepted: December 21, 2012
Published: January 31, 2013
Kai He, Jianpeng Wang, Yongqiang Hou, Xu Li, Heyuan Guan, Fanyu Kong, Shijie Liu, Yunxia Jin, and Kui Yi, "High-spectral-resolution characterization of broadband high-efficiency reflection gratings," Appl. Opt. 52, 653-658 (2013)