Impulsive stimulated Raman scattering in tetragonal GdVO₄single crystal: many-phonon Stokes and cross-cascaded lasing

Abstract

For the first time we excited four-phonon impulsive stimulated Raman scattering (SRS) in tetragonal GdVO4 single crystal under near-IR femtosecond pumping. All of its recorded χ(3)-nonlinear Stokes cascaded and cross-cascaded fully coherent lasing emissions were identified at internal vibrations of the [VO4]3− units of the studied vanadate. The obtained new fundamental knowledge could significantly enrich the functional potential of this crystal, which is a host crystal for trivalent lanthanide lasants and attractive gain media for Raman laser converters and self-SRS lasers.

Impulsive SRS in tetragonal t-YVO4, t-GdVO4and monoclinic m-LaVO4vanadate host-crystals for Ln3+-lasant ions

“…In χ (3) —non‐linear femtosecond coherent lasing, all the internal vibrations of vanadium complexes [VO 4 ] 3− of the studied crystals are observed. Some of them were not recorded earlier in steady‐state picosecond SRS‐experiments and in preliminary constant pulse shape femtosecond χ (3) ‐laser measurements .…”

“…Unfortunately, in the study of the high-peak power Ln 3þ :REVO 4 lasers, careful attention is not always given to the SRS issue. Our recent preliminary research on impulsive SRS crystals m-LaVO 4 and t-GdVO 4 showed that the risk of unwanted impulsive self-SRS will be greater at high intra-cavity power [38,39]. Therefore, we report more complete data on the spectral composition of femtosecond ISRS lasing for two tetragonal t-YVO 4 and t-GdVO 4 and monoclinic m-LaVO 4 vanadates.…”

Femtosecond SRS-generation of coherent optical phonons in vanadate crystals m-LaVO4 and t-GdVO4 (SRS-phononics of the crystals)

“…Now, let us discuss briefly the vibronic nature of χ (3) active phonon modes of the m LaVO 4 and t GdVO 4 crystals, which are the vibrations of their structural vanadium complexes [VO 4 ] 3with nearly identical tetrahedral shape [11]. Monoclinic m LaVO 4 exhibits two types of Raman active oscilla tions, A g and B g [6], among which the ISRS lasing modes ω SRS1 ~855 cm -1 and ω SRS3 ~ 820 cm -1 can be the totally symmetric stretching A g (ν s ) of its vanadium complexes [VO 4 ] 3- [12] and the modes ω SRS2 3 70 cm -1 and ω SRS4 ~ 305 cm -1 can belong to the anti symmetric bending A g /B g (δ as ).…”

“…The ISRS generation of the monoclinic m LaVO 4 and tetragonal t GdVO 4 crystals was studied at room temperature on a femtosecond facility based on a ytterbium fiber laser excitation source with λ e 1 .0615 μm and ω e ~ 9421 cm -1 ) and a detecting dif fraction spectrometer with an InGaAs CMOS detec tor (G10768 1024D) [11]. The excitation pulse length was chosen to be ~600 fs, which ensured the impulsive SRS lasing of crystals with the detection of their mul tiphonon spectra with nonoverlapping generation lines.…”

“…The results of this study are given in bold. The ISRS generation spectra for the t GdVO 4 crystal were measured in [11] under similar experi mental conditions. * Steady state Raman gains for the first Stokes IR components ( ) with the participation of the SRS active modes ω SRS1 ~ 855 cm -1 and ω SRS1 ~ 882 cm -1 of the investigated vanadates were estimated as ≥ 4.8 cm GW -1 for m LaVO 4 [6] and ≥ 4.5 cm GW -1 for t GdVO 4 [5].…”