Fourth-harmonic generation via nonlinear diffraction in a 2D LiNbO3 nonlinear photonic crystal from mid-IR ultrashort pulses

作者：Ma, Boqin^*; Kafka, Kyle; Chowdhury, Enam

来源：Chinese Optics Letters, 2017, 15(5): 051901.

DOI：10.3788/COL201715.051901

• RAMAN-NATH DIFFRACTION
• 2ND-HARMONIC GENERATION
• 3RD-HARMONIC GENERATION

Five conical harmonic beams are generated from the interaction of femtosecond mid-infrared (mid-IR) pulses at a nominal input wavelength of 1997 nm with a 2D LiNbO3 nonlinear photonic crystal with Sierpinski fractal superlattices. The main diffraction orders and the corresponding reciprocal vectors involved in the interaction are ascertained. Second and third harmonics emerging at external angles of 23.82 degrees and 36.75 degrees result from nonlinear. Cerenkov and Bragg diffractions, respectively. Three pathways of fourth-harmonic generation are observed at external angles of 14.21 degrees, 36.5 degrees, and 53.48 degrees, with the first one resulting from nonlinear. Cerenkov diffraction, and the other two harmonics are generated via different cascaded processes.

• 出版日期2017-5-10
• 单位中国传媒大学