We retrieve intensity and phase profiles of 280 fs, 50 MHz optical pulses with 124 aJ coupled pulse energy (960 photons) by second-harmonic generation (SHG) frequency-resolved optical gating, using aperiodically poled LiNbO3 waveguides. The strong nonlinear interaction that is due to confinement within the micrometer-sized waveguide structure and the linearly chirped poling period contribute, respectively, to high SHG efficiency and broad phase-matching bandwidth. The achieved sensitivity is 2.7×10^-6 mW², improving on the previous record for self-referenced complete pulse characterization by 5 orders of magnitude.
© 2005 Optical Society of America
Shang-Da Yang, Andrew M. Weiner, Krishnan R. Parameswaran, and Martin M. Fejer, "Ultrasensitive second-harmonic generation frequency-resolved optical gating by aperiodically poled LiNbO3 waveguides at 1.5 µm," Opt. Lett. 30, 2164-2166 (2005)