Chinese Optics Letters, 2017, 15 (9): 091403, Published Online: Jul. 19, 2018
Narrow-spectral-span spectral beam combining with a nonparallel double-grating structure Download: 1031次
140.2010 Diode laser arrays 140.3290 Laser arrays 140.3298 Laser beam combining 050.1950 Diffraction gratings
Abstract
We propose a nonparallel double-grating structure in a spectral-beam combining technique, where two gratings are placed nonparallel satisfying the Littrow mount in the focal region of the convergent lens. The most attractive advantage of this approach is that it will compress the spectral span into half of its original spectrum, which means the number of combined elements can be doubled in the gain range of diode lasers. Experimental results demonstrate that the CW output power of the combined beam is 30.9 W with a spectral span of 7.0 nm, compared with its original spectrum span of 13.6 nm, and the spectral beam combining efficiency is 70.5%. In consideration that a single grating could have a high efficiency of > 97 % in a bandwidth of over ten nanometers, the efficiency loss of the grating pair should be less than 6%, which is acceptable for most applications, so this method of using double gratings should be highly interesting for practical applications when a nearly doubled number of diode lasers could be combined into one single laser compared with the previous single-grating methods.
Quan Zhou, Changhe Zhou, Na Yu, Chunlong Wei, Wei Jia, Yancong Lu. Narrow-spectral-span spectral beam combining with a nonparallel double-grating structure[J]. Chinese Optics Letters, 2017, 15(9): 091403.