Pulse amplification in a Cr⁴⁺:forsterite single longitudinal mode (SLM) multi-pass amplifier

Abstract

An efficient multi-pass Cr:forsterite master oscillator-power amplifier laser system operating in the single-longitudinal mode was demonstrated and characterized. A significant increase in energy was obtained in a six-pass amplifier configuration giving a maximum value of up to 10.8 mJ, with a good beam quality and without significantly broadening the linewidth or increasing the M 2 . The amplifier performance was evaluated as a function of the pump energy and the number of passes. A Fourier transformation of the laser pulses was performed to confirm the linewidth value measured using a Fabry-Perot etalon.

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

“…In general, the gain value agrees quite well with the experimental values previously measured using similar configurations. 7,10 However, the expected gain, for the two crystals lengths, oscillates between 3.2 and 4 according to the calculations performed before. 7,10 The gain measured experimentally is lower than the expected theoretical one because the theory does not take into account the contribution to the gain reduction caused by the effects of excited-state absorption, passive loss in the rod as well as local heating and thermal lensing.…”

“…7,10 However, the expected gain, for the two crystals lengths, oscillates between 3.2 and 4 according to the calculations performed before. 7,10 The gain measured experimentally is lower than the expected theoretical one because the theory does not take into account the contribution to the gain reduction caused by the effects of excited-state absorption, passive loss in the rod as well as local heating and thermal lensing. 10 N stages E in ( The tuning range of the Cr:forsterite oscillator was measured using an spectrometer (SOLAR LASER SYSTEM, S150-II).…”

“…Most recently, this approach was implemented in a Cr:forsterite amplifier in order to reach 10.8 mJ. 7 Therefore, it was demonstrated that, increasing either the number of stages or the number of passes the extraction efficiency can be improved. However, the efficiency can be significantly enhanced if stage and passage number increase simultaneously.…”

The FAMU experiment: muonic hydrogen high precision spectroscopy studies

“…At present, we have a commercially available single-frequency mode Nd:YAG laser system with output energy > 250 mJ. We have built a multipass multi-stage amplifying system with finely tunable wavelenght and narrow bandwidth at 1.262 µm able to reach 24 mJ [47,48]. To obtain a linewidth of 250 MHz at 6.8 µm, the linewidths of both pump lasers will be narrowed:…”

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

“…If in the time interval between the μp thermalization and the muon transfer to oxygen, the muonic hydrogen atoms absorb a photon at the resonance frequency provided by a laser source, a hyperfine para-to-ortho transition ((1S)F= 0 → (1S)F= 1) is promoted and, in the following collisional de-excitation to the para spin state, they are accelerated by ∼ 0.12 eV [4]. The resonance frequency photon is provided by a tunable high energy MIR laser developed at Elettra Sincrotrone Labs [5]. 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.…”