Author(s): Sun, YQ (Sun, Yong-Qiang); Zhang, JC (Zhang, Jin-Chuan); Cheng, FM (Cheng, Feng-Min); Ning, C (Ning, Chao); Zhuo, N (Zhuo, Ning); Zhai, SQ (Zhai, Shen-Qiang); Liu, FQ (Liu, Feng-Qi); Liu, JQ (Liu, Jun-Qi); Liu, SM (Liu, Shu-Man); Wang, ZG (Wang, Zhan-Guo)

Source: CHINESE PHYSICS B Volume: 30 Issue: 3 Article Number: 034211 DOI: 10.1088/1674-1056/abd6fe Published: FEB 2021

Abstract: A beam steering effect of high-power quantum cascade (QC) lasers emitting at similar to 4.6 mu m was investigated. The continuous wave (CW) output power of an uncoated, 6-mm-long, 7.5-mu m-wide buried-heterostructure QC laser at 25 degrees C was as high as 854.2 mW. The maximum beam steering angle was offset by +/- 14.2 degrees from the facet normal (0 degrees) in pulsed mode. The phenomenon was judged explicitly by combining the diffraction limit theory and Fourier transform of the spectra. It was also verified by finite element method software simulation and the calculation of two-dimensional (2D) effective-index model. The observed steering is consistent with a theory for coherence between the two lowest order lateral modes. Therefore, we have established an intrinsic linkage between the spectral instabilities and the beam steering by using the Fourier transform of the spectra, and further presented an extremely valid method to judge the beam steering. The content of this method includes both three equidistant peak positions in the Fourier transform of the spectra and the beam quality located between once the diffraction limit (DL) and twice the DL.

Accession Number: WOS:000623897600001

ISSN: 1674-1056

eISSN: 1741-4199

Full Text: https://iopscience.iop.org/article/10.1088/1674-1056/abd6fe