Dual-output long-wave infrared sources based on a BaGa₄Se₇ crystal

This paper presents a coherent long-wave infrared source based on a BaGa₄Se₇ crystal with a tuning range from 6.7 to 15 μm. The pump-reflected double-pass configuration effectively reduces the threshold and enables dual-port output. A statistical analysis of the time-series data from forward and backward outputs revealed a strong linear regression relationship. This characteristic enables single-shot synchronous spectroscopic analysis, where the forward output transmits through the sample and the backward output serves as the reference. Compared to traditional asynchronous methods, the synchronous approach offers a shorter scan time and reduced error by minimizing the impact of source fluctuations. This dual-output source shows potential for rapid and accurate spectroscopic analysis in applications such as biomedical diagnostics and atmospheric monitoring.