Frontiers of Mid-IR Lasers Based on Transition Metal Doped Chalcogenides

Octave-spanning Cr:ZnS femtosecond laser with intrinsic nonlinear interferometry

“…Over the past several years, we have reported on incremental progress in the development of polycrystalline Cr:ZnS lasers and amplifiers [4]. Here we present the first octave-spanning system, to the best of our knowledge.…”

“…There are numerous, both more and less established, techniques for MIR fs lasing and frequency comb generation [3]. Ultrafast sources based on Cr:ZnS and Cr:ZnSe are appealing because they allow direct generation and amplification of few-cycle pulses in the range of 2-3 μm [4].…”

“…It is arranged as a full repetition rate single-pass fs amplifier [4]. The prerequisites for generation of an octave-spanning spectrum include: the use of a sub-octave 3-cycle master oscillator with ≈0.5 MW peak power [4], optimization of chromatic dispersion at the input of the amplifier, and optimization of the transverse size of the input beam. Obtained laser parameters are summarized in Fig.…”

Directly diode-pumped, Kerr-lens mode-locked, few-cycle Cr:ZnSe oscillator

“…Solid-state lasers based on Cr 2+ -doped II-VI material, often called the Ti:Sapphire of the mid-infrared, are reliable sources for directly generating ultrashort femtosecond pulses in the 2-3 μm spectral range [21][22][23][24][25]. With recent improvements in output power to Wattlevel and pulse durations down to few optical cycles [26,27], the output has also been effectively down-converted to generate broadband mid-infrared radiation between 3-20 μm [28][29][30]. To date, virtually all mode-locked (ML) Cr:ZnS/ZnSe lasers are pumped by mature rare-earth-doped fiber lasers.…”

Fabrication and characterization of IR‐transparent Fe2+ doped MgAl2O4 ceramics

“…The energy level 5 D of the Fe 2+ ion splits into two levels, 5 E and 5 T 2 and it is suggested that the transition 5 T 2 → 5 E can be used for the mid‐IR laser oscillation similar to Fe 2+ :ZnSe and Fe 2+ :ZnS . Compared with Fe‐doped chalcogenides, polycrystalline Fe 2+ :MgAl 2 O 4 ceramic gain medium can possess a higher volume of active ions due to the absence of the thermal diffusion process of iron from the surface of the sample to a depth of ~1.5 mm at a doping concentration of ~10 19 cm −3 …”