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SRS in di-glycine nitrate (NH2CH2COOH)2 · HNO3 crystals: Observation of high-gain many-phonon nonlinear interactions


  • On the occasion of the 50th anniversary of the discovery of stimulated Raman scattering


Efficient high-gain many-phonon steady-state stimulated Raman scattering (SRS) was excited in the novel χ(3)-active organic crystal of di-glycine nitrate (DGN), (NH2CH2COOH)2 · HNO3, at room temperature under picosecond laser pumping in the visible and near-IR regions. Besides high-order Stokes and anti-Stokes (comb) generation in this centrosymmetric crystal, several cascaded and cross-cascaded χ(3) ↔ χ(3) nonlinear photon–phonon interactions were observed. The recorded Raman-induced lasing wavelengths were identified and attributed to the SRS-promoting optical vibration modes ωSRS1 ≈ 1058 cm−1, ωSRS2 ≈ 2985 cm−1, ωSRS3 ≈ 895 cm−1, and ωSRS4 ≈ 3000 cm−1. The measured large Raman frequency shifts (≈3000 cm−1) and estimated moderately high steady-state Raman gain coefficients (equation image ≥ 6.5 cm · GW−1) make this DGN crystal attractive for a number of new applications in modern laser physics and nonlinear optics.