Ultrasensitive Nonlinear Measurements of Femtosecond Optical Pulses at 1.5μm by Aperiodically Poled Lithium Niobate Waveguides

摘要

Ultraweak, ～300-fs pulses at 1.5 μm are measured by second-harmonic generation intensity autocorrelation and frequency-resolved optical gating using aperiodically poled LiNbO{sub}3 waveguides. Our reference-free scheme can retrieve complex fields with 120-aJ coupled pulse energy, corresponding to a sensitivity of 2 × 10{sup}(-6) mW{sup}2, ～5 orders of magnitude better than the previous record.