Spectral broadening in lithium niobate in a self-diffraction geometry using ultrashort pulses

• Published in: Applied physics. B, Lasers and optics Vol. 122; no. 5; pp. 1 - 7
• Main Authors: Dharmadhikari, Jayashree A., Dota, Krithika, Mathur, Deepak, Dharmadhikari, Aditya K.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.05.2016
• Subjects: Broadband; Coherent scattering; Crystals; Engineering; Femtosecond; Lasers; Lithium niobates; Modulation; Optical Devices; Optics; Photonics; Physical Chemistry; Physics; Physics and Astronomy; Quantum Optics; Spectra; LiNbO3; Stimulate Raman Scattering; Lithium Niobate; Ultrashort Pulse; Femtosecond Laser Pulse
• ISSN: 0946-2171; 1432-0649
• DOI: 10.1007/s00340-016-6423-y

We report on broadband light generation in the impulsive regime in an un-doped lithium niobate (LiNbO 3 ) crystal by two femtosecond laser pulses (36 fs) from a Ti-sapphire laser amplifier. We systematically investigate the role of incident intensity on spectral broadening. At relatively low incident intensity (0.7 TW cm −2 ), spectral broadening in the transmitted beam occurs due to the combined effect of self-phase modulation and cross-phase modulation. At higher incident intensity (10.2 TW cm −2 ), we observe generation of as many as 21 anti-Stokes orders due to coherent anti-Stokes Raman scattering in self-diffraction geometry. Moreover, we observe order-dependent spectral broadening of anti-Stokes lines that may be attributed to the competition with other nonlinear optical effects like cross-phase modulation.