Broadband Nonlinear Optical Modulator Enabled by Transition Metal Pentatelluride Nanosheets Towards Mid-Infrared Regime

The broadband nonlinear optical modulators (NLOMs) are highly required for the versatile optoelectronic applications, especially towards the mid-infrared (mid-IR) regime. Transition metal pentatelluride (TMP), the typical Dirac semimetal, has attracted great attention due to its unique broadband physicochemical properties, which make it an ideal candidate for optoelectronic devices. Here, we prepared HfTe ₅ and ZrTe ₅ nanosheets by liquid-phase exfoliation (LPE) method and experimentally demonstrated their ultra-broadband nonlinear optical modulation performance covering wavelengths from 2.8∼10 μm. In addition, the NLOMs based on HfTe ₅ and ZrTe ₅ nanosheets have been introduced into the mid-IR Er ³⁺ -doped fluoride fiber lasers (EDFFL) to deliver the Q-switched pulses with signal-to-noise ratio (SNR) of 43.4 and 38.3 dB, and pulse duration of 479 ns and 571 ns, respectively. The results show that the TMP nanosheets exhibit broadband nonlinear optical response, which are ideal candidates for stable, broadband mid-IR NLOMs.