Abstract
We report self-starting femtosecond operation of a 180-MHz SESAM-controlled prismless Cr:ZnS laser around 2400 nm at open air and room temperature. Dispersion compensation was achieved by a combination of bulk materials and chirped mirrors. Both soliton- and chirped-pulse operation regimes have been demonstrated with 130 fs (630 fs) pulse duration at 130 (205) mW average output power, respectively. The output power was about 30% higher than for a comparable Cr:ZnSe sample in the same cavity.
Highlights
IntroductionCr2+-doped lasers of the II-VI family [1] operating between 2 and 3.5 m [2] have recently matured to the commercial continuous-wave lasers, with the broadest among existing lasers amplification bandwidth / , making them a practical analogue to Ti:sapphire in the mid-IR wavelength range [3].First reported as a gain-switched free-running pulsed source [1, 4], the Cr2+:ZnS active medium has later been shown to operate in tunable continuous-wave regime [5], as diodepumped [6], microchip [7], high-power [8], and tunable sources with over 1200 nm tuning range [9].The Cr2+:ZnS laser crystal is in many respects similar or even superior to Cr2+:ZnSe
Continuous-wave operation was characterized with a flat high reflector and a prism in the Semiconductor Saturable Absorbing Mirror (SESAM) arm
With a SESAM in place, the threshold pump power increased to ~160 mW as the SESAM provides the highest losses in the cavity (6%) and defines the threshold
Summary
Cr2+-doped lasers of the II-VI family [1] operating between 2 and 3.5 m [2] have recently matured to the commercial continuous-wave lasers, with the broadest among existing lasers amplification bandwidth / , making them a practical analogue to Ti:sapphire in the mid-IR wavelength range [3].First reported as a gain-switched free-running pulsed source [1, 4], the Cr2+:ZnS active medium has later been shown to operate in tunable continuous-wave regime [5], as diodepumped [6], microchip [7], high-power [8], and tunable sources with over 1200 nm tuning range [9].The Cr2+:ZnS laser crystal is in many respects similar or even superior to Cr2+:ZnSe. The absorption band allows efficient pumping using widely available Er:fiber and InGaAsP-InP diode lasers in the 1.55 1.61 μm wavelength range, while the emission band moves towards the middle of the atmospheric water-free window around 2.3 μm, making the ultrashort-pulse operation at open air more stable and environmentally independent. The Cr:ZnS material holds an important promise of much better power and energy handling capability, while retaining comparable gain bandwidth and sufficiently high thirdorder nonlinearity. This makes Cr:ZnS attractive for both high-power and ultrashort pulse generation
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
