We study the nonlinear Raman–Nath diffraction (NRND) of femtosecond laser pulses in a 1D periodic nonlinear photonic structure. The calculated second-harmonic spectra represent frequency combs for different orders of transverse phase matching. These frequency combs are in close analogy with the well-known spectral Maker fringes observed in single crystals. The spectral intensity of the second harmonic experiences a redshift with a propagation angle, which is opposite the case of Čerenkov nonlinear diffraction. We analyze how NRND is affected by the group-velocity mismatch between fundamental and second-harmonic pulses and by the parameters of the structure. Our experimental results prove the theoretical predictions.
© 2014 Optical Society of America
Original Manuscript: May 29, 2014
Revised Manuscript: June 13, 2014
Manuscript Accepted: June 13, 2014
Published: July 14, 2014
A. M. Vyunishev, V. V. Slabko, I. S. Baturin, A. R. Akhmatkhanov, and V. Ya. Shur, "Nonlinear Raman–Nath diffraction of femtosecond laser pulses," Opt. Lett. 39, 4231-4234 (2014)