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A compact Tm:GdVO 4 laser pumped by a 794 nm laser diode generated 6.09 W at 2.29 µm ( 3 H 4  →  3 H 5 Tm 3+ transition) with a high slope efficiency of 30.8% and linear laser polarization (π). The polarized spectroscopic properties of Tm 3+ in GdVO 4 were also revised. The peak stimulated-emission cross section of Tm 3+ is 2.97 × 10 -20 cm 2 at 2280 nm, corresponding to an emission bandwidth of 42 nm for π-polarized light.

In this Letter, a watt-level laser diode (LD)-pumped ∼2.3-µm (on the 3 H 4 → 3 H 5 quasi-four-level transition) laser is reported based on a 1.5 at.% a-cut Tm:YVO 4 crystal. The maximum continuous wave (CW) output power obtained is 1.89 W and 1.11 W with the maximum slope efficiency of 13.6% and 7.3% (versus the absorbed pump power) for the 1% and 0.5% transmittance of the output coupler, respectively. To the best of our knowledge, the CW output power of 1.89 W we obtained is the highest CW output power amongst the LD-pumped ∼2.3-µm Tm 3+ -doped lasers.

In this Letter, the fabrication of large-scale (50.8 mm in diameter) few-layered MoS 2 with physical vapor deposition on sapphire is described. Open-aperture Z-scan technology with a home-made excitation source at 2275 nm was applied to explore its nonlinear saturable absorption properties. The as-grown few-layered MoS 2 membrane possessed a modulation depth of 17% and a saturable intensity of 1.185 MW cm -2 . As a consequence, the deposited MoS 2 membrane was exploited as a saturable absorber to realize a passively Q-switched Tm:YAP laser for the first time, to the best of our knowledge. Pulses as short as 316 ns were generated with a repetition rate of 228 kHz, corresponding to a peak power of 5.53 W. Results confirmed that the two-dimensional layered MoS 2 could be beneficial for mid-infrared photonic applications.