Heterojunctions hold great potential for optical modulation

As a human eye-safe spectral window, 2 μm band pulsed laser devices hold significant application value in medical, scientific research, industrial, and other fields. The exploration of novel saturable absorber (SA) materials operating in the 2 μm band has long been a focal point of interest for researchers both domestically and internationally. However, single-layer 2D material films are prone to oxidation, exhibit low damage thresholds, and suffer from poor stability, which severely limits their service life as components in all-solid-state laser devices. The 2D material heterojunctions not only preserves the broad bandwidth and excellent nonlinear optical properties inherent to 2D materials but also significantly enhances their stability.

The research team led by Professor Wei Xia from Jinan University, China, has a keen interest in lasers. In all-solid-state lasers, the researchers employed liquid phase exfoliation (LPE) and mechanical exfoliation (ME) methods to fabricate BP/ReS₂ heterojunction SAs, respectively. The nonlinear absorption characteristics of two kinds of SAs were systematically investigated. The results indicate that BP/ReS₂ heterojunctions hold significant application potential in all-solid-state pulsed lasers. The work entitled “Nonlinear saturable absorption properties of BP/ReS₂ heterojunction and its application in 2 μm all-solid-state lasers” was published on Frontiers of Optoelectronics (published on June 11, 2025).