Observation of nonlinear lasing χ⁽³⁾-effects in highly transparent nanocrystalline Y₂O₃ and Y₃Al₃O₁₂ ceramics

Abstract

Multi-wavelength nonlinear parametric χ (3) -effects were observed in highly transparent Y 2 O 3 and Y 3 Al 5 O 12 nanocrystalline ceramics under picosecond pumping at 300 K. All recorded Stokes and anti-Stokes components in the visible and near IR were identified and attributed to the stimulated Raman scattering active vibration modes of these novel optical and laser-host crystalline materials. For both materials, the steadystate first-Stokes Raman gain coefficient was estimated at a wavelength of around 1 µm.

Laser crystals and ceramics: recent advances

“…In much the same manner as for the Y 3 Al 5 O 12 crystalline compounds, in the case of Y 2 O 3 single crystals and ceramics the spontaneous Stokes Raman spectra are practically indiscernible (Fig. 19) Figure 18 Steady-state SRS spectra of undoped Y2O3 ceramics (l = 40 mm) recorded at 300K with pumping in a) the near-IR and b) the visible regions [351]. The inset shows a schematic of the picosecond laser pumping set-up used.…”

“…16. Figure 19 Room temperature spontaneous Stokes Raman scattering (Ag, Fg) spectra of undoped Y2O3 ceramics and single crystals [351]. Zero corresponds to Ar ion laser excitation radiation at a wavelength of 0.5145 µm.…”

Observation stimulated Raman scattering in nanocrystalline Sc2O3 ceramics

“…The newest laser ceramics based on refractory cubic Y 3 Al 5 O 12 garnets and RE 2 O 3 sesquioxides were obtained by the revolutionary vacuum not-pressing sintering method, where the raw material was prepared by nanocrystalline technology [13]. The high optical quality of these novel optical and laser materials was evidenced also by our observation in Y 3 Al 5 O 12 and Y 2 O 3 ceramics high-order Stokes and anti-Stokes generation in the visible and near-IR by efficient stimulated Raman scattering (SRS) and Raman induced four-wave mixing (RFWM) [4,7]. Quite recently we reported one-micron CW laser action of Yb…”

Stimulated Raman scattering in new organic and inorganic crystalline materials

“…Mixing of (2) and (3) nonlinear effects in one material does not only present new ways to reach new discrete wavelengths it also helps to understand the coupling interactions between the participating electromagnetic fields inside the crystal. Therefore it will be necessary to investigate more materials in the future that show different kinds of nonlinear optical phenomena.…”

“…Raman active crystals with non-centrosymmetric structure allow simultaneous generation of (2) and (3) effects. If the nonlinear dielectric susceptibilities d SHG ijk have sufficiently high values effective frequency doubling is possible in combination with cascading stimulated Raman scattering.…”