1.06-GHz Diode-Pumped Modelocked 2.4-μm Cr:ZnS Laser

Short wavelength infrared (SWIR) modelocked lasers can provide access to the molecular fingerprint region of a wide variety of molecules, while optical frequency combs with gigahertz line spacing are particularly attractive for high-sensitive, comb-line-resolved rapid measurements [1], [2]. Chromium doped: zinc sulfide (Cr:ZnS) solid-state lasers have a uniquely broad emission bandwidth in the 2–3 μm SWIR range, supporting high-power modelocked operation [3], [4]. Stable, self-starting modelocking with multi-gigahertz operation of Cr:ZnS lasers has been demonstrated using high-quality InGaSb-based SESAM [3]. However, these systems rely on a bulky and expensive Er:fiber amplifier for pumping. Diode-pumped counterparts offer a compact and cost-effective alternative; however, diode lasers have poorer beam quality, lower power, and lower brightness making gigahertz modelocking more challenging. A SESAM-modelocked Cr:ZnS oscillator with a repetition rate of 435 MHz is recently achieved [5]. In this work, we present a diode-pumped gigahertz Cr:ZnS laser for the first time.