Few-layer TiSe₂ as a saturable absorber for nanosecond pulse generation in 295  μm bulk laser

Abstract

1T-phase titanium diselenide (1T-TiSe), a model two-dimensional (2D) transition metal dichalcogenide, has attracted much attention due to its intriguing electrical and optical properties. In this work, a 1T-TiSe-based high-quality large-area saturable absorber (SA) (1T-TiSe-SA) was successfully fabricated with the liquid-phase exfoliation method. With the as-prepared 1T-TiSe-SA, a stable, passively Q-switched laser operating at 2.95 μm was first realized. Under an absorbed pump power of 3.35 W, the maximum average output power was 130 mW with a slope efficiency of 5%. A pulse width of 160.5 ns was obtained, which is the shortest among 3.0 μm passively Q-switched lasers ever achieved with 2D materials as SAs, to the best of our knowledge. The results indicate that 1T-TiSe is a promising alternative as a nonlinear optical modulator for short-pulse laser generation near the 3.0 μm mid-infrared region.

2D Layered Materials: Synthesis, Nonlinear Optical Properties, and Device Applications

“…Since 2010, Q‐switched solid‐state lasers based on layered materials including graphene, topological insulators, TMDCs, BP, and g‐C 3 N 4 , have been developed rapidly, as shown in Table . It can be seen that these lasers have excellent performance in output power, pulse width, repetition rate, and peak power.…”

“…For example, the researchers achieved the visible‐light Q‐switched laser using topological insulators . In addition, 3‐µm Q‐switched lasers based on layered materials have also been widely studied . Second, besides single‐wavelength operation, multiwavelength Q‐switched lasers have been also developed .…”

Recent Progress in 2D Material‐Based Saturable Absorbers for All Solid‐State Pulsed Bulk Lasers

“…However, with the development of the fabrication method, one can introduce defects in the 2D materials to tune the operation band, as well as prepare heterostructures with different materials. For passively Q‐switched MIR ASSPLs, the shortest pulse width for 2.0, 2.4, 2.9 µm laser operation are 181 ns (with BP SA), 157 ns (with graphene SA), and 160.5 ns (with 1T‐TiSe 2 SA) . For CW mode‐locking operation, the shortest pulse width for 2.0 and 2.4 µm laser operation are 354 fs (with graphene SA) and 41 fs (with graphene SA) …”

“…Our group used monolayer graphene and BP as SAs and realized MIR passively Q‐switched laser output at 2.95 µm, generating shortest pulse widths of 937.5 and 194.3 ns, respectively (Figure d) . With TMDs as the SA, the minimum pulse width with 1T‐TiSe 2 as the SA was 160.5 ns (Figure c) . It is more difficult to obtain CW mode‐locked lasers operating at the 3.0 µm wavelength band than those operating at the 2.4 µm wavelength band due to the strong absorption of water and the energy state structure of the laser crystal.…”

Nonlinear photoresponse of metallic graphene-like VSe2 ultrathin nanosheets for pulse laser generation

“…Inspired by the outstanding performance of graphene [6][7][8][9], several different types of 2D materials, such as topological insulators (TIs) [10,11], black phosphorus (BP) [12,13], and transition metal dichalcogenides (TMDCs), have been extensively used in the field of pulsed fiber lasers. Especially, as novel 2D materials, various TMDCs (WS 2 [14,15], MoS 2 [16,17], WSe 2 [18], MoSe 2 [19], TiS 2 [20], TiSe 2 [21,22], SnS 2 [23], etc.) have been widely studied as optical modulator at different wavelengths due to their ultrafast recovery time, high nonlinearity, high damage threshold, and suitable band gaps.…”