Frequency down-conversion of a chirped Ti:sapphire laser pulse with BaWO4 Raman shifter and second-order nonlinear crystal. (1st September 2022)

• Record Type: Journal Article
• Authors: Kinyaevskiy, I O; Koribut, A V; Grudtsyn, Ya V; Seleznev, L V; Kovalev, V I; Pushkarev, D V; Dunaeva, E E; Ionin, A A
• Is Part Of: Laser physics letters. Volume 19:Number 9(2022)
• Publication Date: 2022-09-01
• Subjects: frequency down-conversion -- stimulated Raman scattering -- difference frequency generation -- Ti:sapphire laser -- chirped laser pulse -- mid-IR range; Lasers -- Periodicals; Physics -- Periodicals; 621.366
• DOI: 10.1088/1612-202X/ac7f36
• Languages: English
• ISSNs: 1612-2011

Abstract

Abstract: We experimentally carried out frequency conversion of a chirped and stretched up to 200 ps near-IR 90 fs Ti:Sapphire laser pulse into the mid-IR through difference frequency generation in either GaSe or LiGaS2 crystal. The crystal was pumped by laser radiation that passed through a BaWO4 crystal, where Stokes frequency-shifted radiation (signal wave) was generated through SRS. The generated ∼60 nJ mid-IR pulse had a central wavelength of 11.1 μ m and FWHM spectral width of about 0.2 μ m, which made it possible to achieve a pulse duration of ∼0.9 ps after its compression. The mid-IR pulse generation efficiency was ∼10 −3 % at SRS efficiency of 3%. To the best of our knowledge, this all solid-state scheme combining Raman shifting and second-order nonlinear crystals achieves the frequency down-conversion of femtosecond near-IR laser pulses to ∼11 μ m radiation for the first time.