High Power Laser Science and Engineering, Volume. 10, Issue 1, 010000e5(2022)
Spatiotemporal coupling investigations for Ti:sapphire-based multi-PW lasers Editors' Pick
Fig. 1. Schematic of a Ti:sapphire-based multi-PW amplification chain.
Fig. 2. Normalized input Gaussian spectrum (black line) and amplified spectrum (red line) with a total effective gain of 105: (a) without saturation effect; (b) under gain narrowing and gain saturation; (c) with gain narrowing and (d) with gain saturation compensation performed by two spectral filters, SF1 and SF2, set up in the chain.
Fig. 3. (a) Normalized experimental spectral input and spatially averaged spectral output, calculated for a 300 J, 14 cm ‘top-hat’ beam, amplified from a 5 mJ Gaussian beam. (b) Output beam spectrum radial evolution: eight output spectra from the beam center (red curve) and the edge of each circular sub-section.
Fig. 4. Normalized near-field intensity
Fig. 5. Series of normalized output fluence
Fig. 6. Normalized encircled energy of the focus with (red curve) and without (blue curve) the analyzed spatiospectral gain inhomogeneity.
Fig. 7. (a) Compressed pulses and (b) induced spectral phases calculated after a double-pass compressor in three different cases: with a perfect grating alignment (black curve); with a default of grating parallelism Δθ = 0.01° (blue curve); and the default compensated by adjusting the compression distance (red curve). (c) Focal spot movement in
Fig. 8. (a) Measured residual spatial phases of the gratings G2 and G3 of the Apollon 10 PW compressor (ellipse: 900 mm long axis and 400 mm short axis). (b) Induced degradations in spatiotemporal Strehl ratio (blue curve) and in compressed pulse duration (orange curve). (c) Normalized encircled focal spot energy and (d) temporal contrast observed in the range of ±200 fs around the main pulse, when the spatial phase amplitude increases for all four gratings in the Apollon 10 PW compressor with the phase amplitude multiplying factor rising from 0 (red curves) to 8 (purple curves).
Fig. 9. (a) Normalized spectra in the beam center and two beam edges: spectral modulation is generated by the limited size of the grating G2 (Apollon 10 PW compressor). (b) Normalized peak power of the compressed pulse (in log) with and without spectral clipping. (c) Far-field S-T laser intensity observation around the focal spot (±600 μm in
Fig. 10. Focus caustic fluence in the
Fig. 11. (a) Measured spectral phases in P- and S-polarizations generated by MLD and MMLD mirror coatings. (b) Laser pulse peak power observed at the focus in log-scale: black, mirror coating without any spectral phase; red, mirror with MMLD coating; blue, mirror with MLD coating.
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Ji Ping Zou, Hervé Coïc, Dimitris Papadopoulos. Spatiotemporal coupling investigations for Ti:sapphire-based multi-PW lasers[J]. High Power Laser Science and Engineering, 2022, 10(1): 010000e5
Category: Research Articles
Received: Oct. 12, 2021
Accepted: Dec. 27, 2021
Published Online: Feb. 10, 2022
The Author Email: Ji Ping Zou (ji-ping.zou@polytechnique.edu)