# Table-top high-energy 7 um OPCPA and 260 mJ Ho:YLF pump laser

## TL;DR

This paper reports a compact, high-energy mid-infrared laser system at 7 um capable of delivering TW-level pulses, with innovative chirp inversion techniques enabling efficient pulse compression and high harmonic generation.

## Contribution

The work introduces a novel, all-optically synchronized laser system combining an Er:Tm:Ho:fiber MOPA, ZGP OPCPA, and Ho:YLF amplifier for high-energy, ultrashort mid-infrared pulses.

## Key findings

- Achieved 260 mJ pump energy at 2052 nm with 16 ps duration.
- Compressed 7-um pulses to 8 optical cycles (188 fs) with 93.5% efficiency.
- Generated high harmonics up to order 13 in ZnSe, demonstrating high pulse quality.

## Abstract

We present the state of the art of a compact high-energy mid-infrared laser system for TW-level 8-cycle pulses at 7 um. This system consists of an Er:Tm:Ho:fiber MOPA which serves as the seeder for a ZGP-based OPCPA chain in addition to a Ho:YLF amplifier which is Tm:fiber pumped. Featuring all-optical synchronization, the system delivers 260-mJ pump energy at 2052 nm, 16-ps duration at 100 Hz with a stability of 0.8 % rms over 20 min. We show that chirp inversion in the OPCPA chain leads to excellent energy extraction and aids in compression of the 7-um pulses to 8 optical cycles (188 fs) in bulk BaF2 with 93.5 % efficiency. Using 21.7 mJ of the available pump energy, we generate 0.75-mJ-energy pulses at 7 um due to increased efficiency with a chirp-inversion scheme. The pulse quality of the system's output is shown by generating high harmonics in ZnSe which span up to harmonic order 13 with excellent contrast. The combination of the passive carrier-envelope phase stable mid-infrared seed pulses and the high-energy 2052 nm picosecond pulses makes this compact system a key enabling tool for the next generation of studies on extreme photonics, strong field physics and table-top coherent X-ray science.

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Source: https://tomesphere.com/paper/1906.08163