Diode-pumped gigahertz modelocked Cr:ZnS laser at 2.36 µm

Gigahertz modelocked lasers operating in the crucial 2-3 µm spectral range are highly sought after for numerous applications. However, they currently rely on bulky and expensive fiber amplifiers for pumping. This paper presents the first, to our knowledge, diode-pumped gigahertz modelocked laser operating at 2.36 µm, utilizing Cr:ZnS as the gain medium and an InGaSb SESAM as the saturable absorber. The modelocked laser emits 199 fs pulses with an average power of 268 mW at a record high 1.06 GHz repetition rate for diode laser pumping, achieving a peak power exceeding 1 kW. The laser exhibits excellent long-term and short-term stability with an integrated relative intensity noise of 0.09% in the frequency interval of 10 Hz-10 MHz. The demonstrated cost-effective, compact yet sufficiently powerful, low-noise, high-repetition-rate femtosecond laser in the short-wave infrared range is a promising source for rapid molecular spectroscopy and efficient nonlinear conversion applications.