24 mJ Cr+4:forsterite four-stage master-oscillator power-amplifier laser system for high resolution mid-infrared spectroscopy

Abstract

We present the design of a Cr:forsterite based single-frequency master-oscillator power-amplifier (MOPA) 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 midinfrared (MIR) spectral range, and will be a key building block in a system for high-resolution muonic hydrogen spectroscopy in the 6.8 micron range.

Laboratory tests for MIR light detection and transport with specialty optical fibres

“…1. The Cr:Fo master-oscillator power-amplifier (MOPA) [8]. It is made of a Cr:Fo based oscillator delivering a very narrow linewidth (0.5 pm), single longitudinal mode (SLM) pulsed laser light centred at 1262 nm and a four-stage amplifier unit.…”

“…The resonance frequency photon is provided by a tunable (near 6.78 µm) high energy Mid-Infrared (MIR) laser source based on a difference frequency generation (DFG) nonlinear process. The laser system uses a non-linear crystal and nanosecond pulses generated by single frequency Nd:YAG and Cr:forsterite [7,8] lasers at 1064 nm and 1262 nm, respectively. The number of atoms that have undergone the above sequence can be determined by observing a change of the time spectrum distribution of the characteristic X-rays emitted after the transfer of the muon from the muonic hydrogen to the nucleus of oxygen added to the hydrogen target.…”