New possibilities to use the zircon-type YVO₄ and GdVO₄ Raman-active crystals for extreme SRS-radiation pulse shortening higher than 30 times down to the inverse value of the vibrational Raman line width in a synchronouslypumped crystalline Raman laser with combined long (ν₁) and short (ν₂) shift Raman conversion have been found. It is caused by strong broadening of the short-shift bending vibration ν₂ line in the spontaneous Raman spectrum of these crystals. We report characteristics of all-solid-state extracavity Raman lasers based on the 16-mm long a-cut YVO₄ (ν₁ = 889 cm^–1, ν₂ = 376 cm^–1) and GdVO₄ (ν₁ = 882 cm^–1, ν₂ = 382 cm^–1) crystals under synchronous pumping by a 1063-nm 35-picosecond Nd:GdVO₄ laser. Lasing was obtained in the YVO₄ (GdVO₄) Raman laser at not only the ν₁- shifted first Stokes wavelength of 1173 nm (1174 nm), but also at the (ν₁ + ν₂)-shifted Stokes wavelength of 1228 nm (1228 nm) with slope efficiency of 5.8 % (5.0 %) and output pulse energy up to 11 nJ (10 nJ) at 1228 nm. At 50 μm positive detuning of the external cavity length the strongest 30-fold and 42-fold shortening of the (ν₁+ν₂)-shifted Raman radiation pulse down to 1.2 ps and 850 fs in the YVO₄ and GdVO₄ crystals, respectively, has been achieved. These values are close to the inverse values of the ν₂ line widths of 11 cm^–1 and 24 cm^–1, respectively.

Date Published: 30 April 2019
PDF: 6 pages
Proc. SPIE 11026, Nonlinear Optics and Applications XI, 1102616 (30 April 2019); doi: 10.1117/12.2520921

Published in SPIE Proceedings Vol. 11026:
Nonlinear Optics and Applications XI
Mario Bertolotti; Alexei M. Zheltikov, Editor(s)