silva_2012#

F. Silva, D. R. Austin, A. Thai, M. Baudisch, M. Hemmer, D. Faccio, A. Couairon and J. Biegert, “Multi-octave supercontinuum generation from mid-infrared filamentation in a bulk crystal”, Nat. Commun. 3, 807 (2012)

Source record · Catalogue · Review register

DOI: 10.1038/ncomms1816

Source kind: measurement

Recorded technique: Filamentation of CEP-stable 85-fs, 3.1-um pulses (OPCPA, 160 kHz, 6.9 uJ, 76 MW) in a 2-mm YAG plate; angularly resolved spectra 450-4500 nm with three spectrometers, f-2f stability. Simulated with a carrier-resolving forward Maxwell equation (Eqs. 1-3) with Keldysh ionization and Drude avalanche (Methods).

Materials in structured entries: YAG

Dataset quantities: avalanche_coefficient, band_gap, electron_collision_time, multiphoton_ionization_cross_section, nonlinear_index

Contents: 5 datasets; 1 formula.

Curation notes#

Article pages 1-6 (Nat. Commun. 3:807). Identity validated with warnings (the library’s caption-layout check); title, authors and journal checked against page 1.

MEASURED (no curated quantity): the continuum spans 450-4500 nm; ‘The peak power was 76 MW, which is approximately three times above the critical power for YAG’ (p. 2), so P_cr ~ 25 MW is implied but not printed; induced ellipticity below 0.1; f-2f phase standard deviation 259 mrad over 10 min. FOCUSING (finding): the text says ‘focussed by a 75-mm focal length CaF2 lens to a 1/e2 diameter of 50 um’, Fig. 1’s caption ‘a 50-mm focal length CaF2 lens’ (p. 2; pdf text layer checked). Crystal orientation not stated (the anisotropy of chi(3) ‘with a weak dependence on the crystal orientation’).

SIMULATION INPUTS (Methods, pp. 4-5; datasets assumed): ‘n2 = 7 x 10^-16 cm2 W^-1 (refs 28-30)’ (Kushida et al., Phys. Rev. 167, 289 (1968); Powell et al., Opt. Lett. 14, 1204 (1989); Krupke et al., J. Opt. Soc. Am. B 3, 102 (1986)); ‘ionization potential U_i = 6.5 eV’; ‘an estimated collision time of tau_c = 3 fs, which yields an inverse Bremsstrahlung cross-section sigma = 2.6 x 10^-20 cm2’; chromatic dispersion ‘via a Sellmeier relation (27)’ (Filer et al., Advanced Solid State Lasers 1990, not printed); the alternative multiphoton rate: ‘changing Keldysh’s ionization rates into their multiphoton ionization counterparts ... leads to a fishtail at 550 nm when the cross-section coefficient is decreased below sigma_17 = 1 x 10^-209 s^-1 cm34 W^-17’ (p. 5; 6.5 eV/0.400 eV = 16.3, so 17 photons: checked). The ionization rates are ‘shown in Supplementary Fig. S2’: the supplementary information is not in the library.

FINDINGS (2026-09-26). (1) sigma = 2.6e-20 cm2 is not the Drude cross section for tau_c = 3 fs at 3.1 um: e^2 tau_c/(m_e n0 eps0 c (1 + omega0^2 tau_c^2)) = 7.37e-17/n0 cm2, so 2.6e-20 would need n0 ~ 2800; cheng_2018 takes the same tau_c = 3 fs ‘from [4]’ (this paper) and gets 2.06e-17 cm2 at 2.05 um, which is the Drude value for n0 = 1.80. The evolution equation is printed d_t rho = W(I) + (sigma/U_i) rho E, with E (not I) in the avalanche term, which may be why (a different normalization), but it is not explained. (2) P_cr = lambda^2/(2 pi n0 n2) with n2 = 7e-16 cm2/W at 3.1 um is 21.9/n0 MW, at most 21.9 MW for any n0 >= 1, so 76 MW is at least 3.5 P_cr, not ‘approximately three times’, unless P_cr is defined differently (not stated).

Recorded bibliographic identity status: VALIDATED_WITH_WARNINGS. This concerns identification of the source; it does not establish the scientific correctness of its contents.