Shanghai Optical and Mechanical Institute has made progress in broadband laser modulation materials

Recently, the thin film optics laboratory of Shanghai Institute of Optics and Precision Mechanics, Chinese Academy of Sciences has made progress in broadband laser modulation materials. Relevant achievements were published in Photonics Research with the title of "Broadband 1T polytype tantalum disulfide saturable absorber for solid state bulk lasers".

1T-TaS2 is a typical strongly correlated electronic material. Its narrow band gap of 0.2eV makes up for the gap between zero-band gap graphene and most two-dimensional optical materials with wider band gap. Combined with its strong light absorption, high carrier concentration and high mobility, 1T-TaS2 has considerable potential in the application of broadband optoelectronic devices.

The researchers prepared 1T-TaS2 low-dimensional thin film material with controllable thickness by improved chemical vapor deposition method. Through transient absorption spectroscopy and Z-scan technology, they systematically studied the ultrafast carrier dynamics and nonlinear optical absorption response of 1T-TaS2 thin film in the range of 400-1100nm and 515-2500nm, and found that it has fast photogenerated carrier recombination life and wide band (0.5-2.5 μ m) Saturation absorption phenomenon. Under 1030 nm laser irradiation, the nonlinear absorption coefficient of 1T-TaS2 film is - 22.60 ± 0.52 cm MW - 1, which is better than other typical two-dimensional saturable absorption materials (such as graphene, black phosphorus, molybdenum disulfide, etc.) under similar experimental conditions. Based on the above excellent nonlinear optical properties, 1T-TaS2 saturable absorber was prepared μ Passive Q-switched pulse laser output with multiple wavelengths is realized in the range of m.

The strong correlation material represented by 1T-TaS2 provides a unique material system for photoelectric materials, and is expected to provide new optical materials and laser modulation devices with excellent performance for pulse lasers in wide band, especially in mid-infrared band.

This work has been supported by the National Key R&D Program, the National Natural Science Foundation of China, the China Postdoctoral Science Foundation, and the Special Research Assistant of the Chinese Academy of Sciences.

Source: Shanghai Institute of Optics and Precision Machinery, Chinese Academy of Sciences