Progress in ultrafast, mid-infrared optical parametric chirped pulse amplifiers pumped at 1 µm

Abstract

With diode-pumped Yb laser technology reaching maturity, average power scaling of multi-GW, few-cycle, short-wave and mid-infrared (MIR) optical parametric amplifiers (OPA's) to the 100-W level has become a reality. Well established, commercially available oxide crystals offer a relatively straightforward solution in the 1.4-4-µm spectral range. Extension of the spectral coverage of high-power OPA's beyond 5 µm may be enabled by novel, wide-bandgap non-oxide crystals with growth processes still under major development and optimization. Here, we present our results on the nonlinear optical properties of oxide (LiNbO3, KTiOAsO4) and non-oxide (LiGaS2, BaGa4S7) crystals and the resulting 100-kHz, ultrafast infrared OPA's based on these materials. The reported data provide design parameters and guidelines for high-average-power MIR OPA's pumped by Yb lasers both below and above 5 µm.

Barium Chalcogenide Crystals: A Review

“…In our study, nonlinear absorption in the BGSe crystal was not detected at intensities roughly one-tenth of those reported in [82]. BGS and BGGS crystals exhibit minimum nonlinear refractive indices, approximately ∼0.8 × 10 −14 cm 2 /W, which aligns well with the data for BGS reported by Mero et al [80,81]. We intend to carry out a comprehensive investigation in the upcoming period on the nonlinear absorption and nonlinear refraction of barium chalcogenide crystals.…”

“…The nonlinear absorption and nonlinear refraction results shown in Table 3 were obtained through the Z-scan technique introduced by Sheik-Bahae et al [79]. In the years 2019-2020, Mero et al measured nonlinear refractive indices (n 2 ) of several nonlinear crystals, including LGS and BGS crystals, by exposing the samples to femtosecond pulses at a wavelength of 1.028 µm [80,81]. Experiments carried out in identical conditions reveal that the nonlinear refractive index of the BGS crystal is nearly double that of the LGS crystal (∼0.4 × 10 −14 cm 2 /W).…”