RESUMO
We report on a laser system based on difference frequency generation (DFG) to produce tunable, narrow-linewidth (<30pm), and comparatively high-energy mid-IR radiation in the 6.8 µm region. The system exploits a lithium thioindate (LiInS2) nonlinear crystal and nanosecond pulses generated by single-frequency Nd:YAG and Cr:forsterite lasers at 1064 and 1262 nm, respectively. Two experimental configurations are used: in the first one, single-pass, the mid-IR energy achieved is 205 µJ. Additional increments, up to 540 µJ, are obtained by performing double-pass through the nonlinear crystal. This laser has been developed for high-resolution photon-hungry spectroscopy in the mid-IR.
RESUMO
We present the design of a Cr:forsterite based single-frequency master-oscillator power-amplifier laser system delivering much higher output energy compared to previous literature reports. The system has four amplifying stages with two-pass configuration each, thus enabling the generation of 24 mJ output energy in the spectral region around 1262 nm. It is demonstrated that the presented Cr:forsterite amplifier preserves high spectral and pulse quality, allowing a straightforward energy scaling. This laser system is a promising tool for tunable nonlinear down-conversion to the mid-infrared spectral range and will be a key building block in a system for high-resolution muonic hydrogen spectroscopy in the 6.8 µm range.
