.. This file is generated by docs/source/_ext/benchmark_pages.py: do not edit it. Rueda et al. 2021: 0.29 mJ, 42 fs -> 8 fs, Ar 1500 mbar, 11 passes ================================================================== **0.29 mJ, 42 fs -> 8 fs, Ar 1500 mbar, 11 passes (Rueda et al., Opt. Express 29, 27004, 2021)** - Paper: P. Rueda et al., Opt. Express 29, 27004 (2021), `10.1364/OE.435086 `__ - Script: `benchmark/bench_rueda2021_8fs.py `__ - Checks: 4 within tolerance, 0 outside .. note:: **Calibrated parameter.** ``energy`` = 145 µJ instead of 290 µJ in the paper: x 0.5, as in the authors' own simulation (pedestals, wavefront aberrations). Paper and model --------------- From the docstring of the script: what the paper describes, what the simulation uses, and what it leaves out. .. code-block:: text Benchmark: 0.29 mJ, 42 fs -> 8 fs in a compact argon-filled MPC (lens-frame solver). P. Rueda, F. Videla, T. Witting, G. A. Torchia, F. J. Furch, "8 fs laser pulses from a compact gas-filled multi-pass cell", Opt. Express 29, 27004 (2021), doi:10.1364/OE.435086 (open access). Few-cycle compression of a Ti:Sa CPA in a short, very concentric cell with only 11 passes, hence a high B-integral per pass (the paper estimates 1.5 pi per round trip) and P/Pc ~ 1 at the nominal energy. It complements the two Yb cases: 800 nm, a nearly octave-wide spectrum, self-steepening, and visible space-time couplings, in a small cell. paper used here laser Ti:Sa CPA, 790 nm, 42 fs, nearly Fourier- Gaussian 42 fs at 790 nm, flat phase limited; 290 uJ at the first cavity mirror (measured input not published) energy the authors' own 3D simulation multiplies the energy = 0.5 x 290 uJ = 145 uJ energy by 0.5 to reproduce the spectrum (--set energy=290e-6: nominal) (pedestals, wavefront aberrations) mirrors protected silver, RoC 300 mm, 2", R = 97 % R = 0.97, flat, GDD = 0 flat in the authors' simulation geometry d = 584 mm, 11 passes through the focus MPC(R=0.3, d=0.584, n_passes=11) gas Ar 1500 mbar, n2 from Wahlstrand 2012 Ar 1.5 bar, n2(1 bar) = 1.0e-23 m^2/W compressor 12 bounces PC-70 + fused-silica wedges, -480 fs^2 (assumption: -40 fs^2 per after a 0.5 mm FS exit window bounce) + best fused-silica thickness Measured: Fourier limit 5.0 fs in the text, but 6.2 fs for the spectrum of Fig. 3a (digitised in data/; the simulation is compared with the latter), compressed 8.06 fs (SPIDER; limited by residual third order), more than 6-fold broadening at 1/e, 85 % of the energy in the core of the focused beam. The authors' simulation gives a space-time Strehl-like ratio of 0.91. Transmission: the code counts one mirror bounce per pass (11), the experiment has 10 bounces on the cavity mirrors; the 61.4 % chamber transmission of the paper also includes windows and steering mirrors, so it is only shown for information. Not modelled: ionisation (the paper suspects it explains the stronger blue shift of the measured spectrum; the peak intensity is reported), the measured input spectrum and phase, chirped-mirror GDD oscillations, the spectral response of the silver mirrors. Usage: python bench_rueda2021_8fs.py [--quick] [--device cpu] [--set energy=290e-6] ... Reference run ------------- .. list-table:: :header-rows: 1 :widths: 15 85 * - - * - run - ``run_38b076de``, 2026-11-05 * - code - thunder4d 1.0.0, git ``ae152b3``, LensFrameSimulation * - grid - Grid 120x120x360 (41 MB per field, cpu/scipy) | box 1.13 x 1.13 mm, dx = 9.4 um | T = 822 fs, dt = 2.28 fs | lambda window 450-1307 nm * - steps - phi_max = 0.02 rad, gouy_step = 0.05 rad, 1292 steps * - run time - 11 passes in 6.0 min (cpu, scipy) .. figure:: rueda2021_8fs.png :width: 100% Standard figure of the reference run. Top: transmission, HG₀₀ fraction, homogeneity and B-integral vs pass; beam radius and peak intensity at the cell centre; output spectrum (with the measured or published spectrum when available). Bottom: compressed pulses vs the Fourier limit; output spatio-spectral trace S(θ, λ); fluence on the last mirror. Comparison with the paper ------------------------- .. list-table:: :header-rows: 1 :widths: 16 13 13 9 7 42 * - output - simulation - paper - deviation - status - description * - ``transmission`` - 0.7151 - 0.737 - -3 % - - cell transmission (0.97^10; chamber incl. windows: 0.614) * - ``I_peak_max_Wcm2`` - 1.699e+13 W/cm2 - < 1e+14 - -83 % - ok - max peak intensity at the cell centre (Ar ionisation, order of magnitude) * - ``edge_fraction`` - 4.328e-08 - < 0.001 - -100 % - ok - max fluence fraction outside 70 % of the box (should be ~0) (numerical check) * - ``similarity_measured`` - 0.9513 - - - - spectral similarity with the measurement * - ``ftl_measured_fs`` - 6.178 fs - - - - Fourier limit of the measured (digitised) spectrum * - ``ftl_fs`` - 6.284 fs - 6.2 ±10% - +1 % - ok - Fourier limit (integrated spectrum) (FTL of the measured spectrum (Fig. 3a); text: 5.0 fs) * - ``fwhm_measured_pulse_fs`` - 8.419 fs - - - - FWHM of the measured (digitised) pulse * - ``comp_fs`` - 6.852 fs - 8.06 - -15 % - - compressed, -480 fs2 + 6.92 mm FS (SPIDER, limited by residual TOD) * - ``broadening_1e`` - 7.444 - > 6 - +24 % - ok - spectral width at 1/e, output / input (frequency) (> 6-fold at 1/e) * - ``core_energy_fraction`` - 0.9893 - 0.85 - +16 % - - far-field energy within diameter pi x w (1/e2 half width) (measured, focused beam) Other outputs ------------- .. list-table:: :header-rows: 1 :widths: 20 18 62 * - output - simulation - description * - ``w0_um`` - 110.2 um - linear eigenmode waist (1/e2 radius) * - ``w_mirror_um`` - 675 um - linear mode on mirror (1/e2 radius) * - ``w0_injected_um`` - 110.2 um - injected waist (linear) * - ``P_over_Pc`` - 0.4900 - input peak power / critical power * - ``B_estimate_rad`` - 42.45 rad - B-integral, matched-mode estimate * - ``B_rad`` - 25.14 rad - B-integral, on-axis peak * - ``F_mirror_max_Jcm2`` - 0.0340 J/cm2 - max fluence on the mirrors * - ``eta00_final`` - 0.9911 - HG00 fraction, output * - ``M2x`` - 1.003 - M2 x (spectrally weighted) * - ``M2y`` - 1.003 - M2 y (spectrally weighted) * - ``w_breathing`` - 0.3514 - beam-size oscillation (max-min)/w_in * - ``span20_nm`` - 343.1 nm - -20 dB spectral width * - ``rms_width_nm`` - 63.43 nm - RMS spectral width * - ``lambda_centroid_nm`` - 779.9 nm - spectral centre of mass * - ``best_gdd_fs2`` - -208.7 fs2 - GDD maximising the peak power * - ``best_comp_fs`` - 8.174 fs - compressed with the best GDD * - ``best_peak_ratio`` - 0.7085 - peak power / Fourier limit (best GDD) * - ``best_peak_power_GW`` - 10.66 GW - compressed peak power (best GDD) * - ``V_weighted_x`` - 0.9994 - homogeneity, intensity weighted in 1/e2 (x) * - ``V_min_fwhm`` - 0.9994 - min homogeneity within FWHM * - ``V_min_e2`` - 0.9947 - min homogeneity within 1/e2 * - ``comp_peak_ratio`` - 0.8752 - peak power / Fourier limit (paper compressor) * - ``fs_thickness_mm`` - 6.915 mm - fused silica needed on top of the chirped mirrors Measured data ------------- Curves digitised from the paper, in ``benchmark/`` (see the header of each file for the figure and the units): - ``spectrum``: `data/rueda2021_spectrum.csv `__ - ``pulse``: `data/rueda2021_pulse.csv `__ Reproducing ----------- .. code-block:: bash cd benchmark python bench_rueda2021_8fs.py --device cpu python analyze.py rueda2021_8fs