Semiconductor laser with a holographic selector

A study was made of a semiconductor laser with a holographic selector in an external resonator. The influence of the strength of feedback on the threshold characteristics , on the tuning range in the process of emission of a narrow spectral line, and on the coherence of the radiation was observed. The presence of a selector reduced the threshold current of a heterostructure laser by 26% without an antireflection coating on the end, a spectral line 0.015 nm wide was emitted for currents exceeding the threshold value by a factor of about 2.5, and the tuning range was 15 nm.