Generation of radiation in a resonator under conditions of stimulated Raman scattering in Ba(NO₃)₂, NaNO₃, and CaCO₃crystals

Abstract

The diagrammatic cumulant expansion for the periodic Anderson model with infinite Coulomb repulsion (U = ∞) is considered here for an hypercubic lattice of infinite dimension (d = ∞). The nearest neighbour hopping of the uncorrelated electrons is described exactly by a conduction band, while two different models of hybridization are treated as a perturbation. The same type of simplifications obtained by Metzner for the cumulant expansion of the Hubbard model in the limit of d = ∞, are also shown to be valid for the periodic Anderson model. The derivation of these properties had to be modified because of the exact treatment of the conduction band. § Associate Member of ICTP,

Measurements of Raman gain coefficient for barium tungstate crystal

“…The Raman gain coefficient of barium tungstate was estimated to be 38 cm/GW at 532 nm. This is only 30% less than the Raman gain coefficient of a barium nitrate crystal, which has a record Raman gain value of 47 cm/GW at 532 nm [5,6]. The vibronic dephasing time of the SRS-active mode in BaWO 4 is much shorter (6.6 ps) than that of barium nitrate (26 ps) [1].…”

Q-switched nanosecond Nd3+:Ca(NbO3)2crystalline self-Raman laser with single-step cascade SE (λSE= 1.0615μm of4F3/2→4I11/2channel) → SRS (λSt1 = 1.1741μm of ωSRS≈ 904 cm-1promotion vibration mode) wavelength conversion

“…The distinctive features of this type of wavelength (frequency) converters are that in these crystals stimulated emission (SE) generation and χ (3) nonlinear conversion processes can occur simultaneously, simplified the design of laser devices with very attractive practical potential. Some of them are commercially Laser Phys.…”

Wavelength-versatile visible and UV sources based on crystalline Raman lasers

“…When considering the total conversion to multiple-Stokes lines, the efficiencies are notably higher. The earliest external-cavity Raman laser demonstrations by Karpukhin and Stepanov [85], which employed Ba(NO 3 ) 2 , NaNO 3 and CaCO 3 and a Q-switched 532 nm pump laser, reported overall conversion efficiencies to the Stokes of up to 65%. Mildren et al [83] demonstrated 64% conversion to combined second and third Stokes (589 and 621 nm) for the 901 cm À1 Raman shift of KGW.…”

“…The curvature of the resonator optics and the parameters of the pump beam should be selected to maximise pump and resonator mode overlap. Note, however, in some cases the gain can be very high and unstable resonators can be used to improve beam quality [44,85]. The gain volume in the resonator is most often dictated by the power and beam characteristics of the pump laser and typically the Raman-active material is chosen such that its length is equal to the confocal length of the pump beam.…”