Stimulated Raman scattering and cascaded nonlinear laser (χ⁽³⁾ ↔ χ⁽²⁾) effects in tetragonal non-centrosymmetric Li₂B₄O₇ single crystals

Abstract

Multiple stimulated Raman scattering (SRS) and cascaded nonlinear χ (3) ↔ χ (2) generation in tetragonal non-centrosymmetric Li2B4O7 crystal were observed under picosecond Nd 3+ :Y3Al5O12 laser excitation. All registered Stokes and antiStokes lasing components in the visible and near-IR were identified and attributed to the SRS-promoting vibration modes of the studied crystal. We classify the Li2B4O7 crystals as a promising media for up-and down-Raman laser-frequency converters. In the work a brief review of nonlinear-laser properties of SRSactive borate crystals is given.Example of a grown crystal of Li2B4O7, together with a crystal sample that were cut from the bulk of the crystal

High-order stimulated Raman scattering and cascaded nonlinear lasing effects in crystals of (χ(3)→ χ(2))-active orthorhombic PbB4O7

“…The PbB 4 O 7 crystal is of special interest for studies of cascaded χ (3) → χ (2) processes due to its rather high SHG coefficients with the lack of phase matching.…”

“…Nonlinearity χ (2) and χ Possible applications UV/VIS electro-optic Q-switchers/modulators, surface acoustic wave devices [15], Raman laser converters a) Limit of probable error in parentheses. b) Original data from [12] that are given in standard setting Pmn2 1 were transformed to the non-standard setting Pnm2 1 , that had already been used for all previous physical investigations.…”

“…For the excitation of single-pass lasing Raman Stokes components in oriented orthorhombic non- [2,20]). Its beam with nearly Gaussian profile is focused into the (χ (3) + χ (2) ) active PbB 4 O 7 samples with a lens (f = 250 mm), resulting in a beam-waist diameter of about 160 µm.…”

“…From the full set of polarized Raman spectra (obtained using Bruker FT100/S spectrometer with CW one-micron Nd 3+ :Y 3 Al 5 O 12 pumping laser) of an oriented PbB 4 O 7 crystalline sample Fig. 5 shows two A 1 -spectra which are recorded in excitation geometries that are close to the pumping condition used for the recording of the cascaded lasing (χ (3) → χ (2) )-spectra spectra showed in Fig. 4.…”

Orthorhombic tris(glycine) zinc chloride Gly3��ZnCl2��� a new semi-organic many-phonon SRS crystal manifesting different nonlinear-laser (��(3)+��(2)) interactions under one-micron picosecond pumping

“…This rather rare nonlinear-laser phenomenon was observed before only in uniaxial single crystals (see, e.g. LaBGeO 5 [26], KH 2 PO 4 (KDP) [27], Li 2 B 4 O 7 [28], and Ba 2 MgGe 2 O 7 [29]). …”