Improved Nonlinear Optical Devices

Researchers at Stanford are advancing a new class of nonlinear optical devices that operate with significantly lower energy requirements than previous platforms. Commercial applications include various photonic applications; sensors; telecom (fast modulators); analytical instruments, and spectrometers. Specifically, the researchers have developed devices that combine quasi-phase-matching with nanophotonic waveguides to achieve efficient nonlinear interactions of femtosecond pulses over length scales an order of magnitude larger than the current state of the art. The crucial breakthrough is the change in dispersion due to sub-wavelength confinement; light propagates with a different velocity in nanophotonic waveguides, and the waveguide geometry can be chosen to achieve simultaneous group-velocity matching between multiple interacting waves and reduced higher-order dispersion. Using these methods, the researchers have developed and experimentally demonstrated several devices that achieve efficient spectral broadening and harmonic generation with the lowest energy requirements demonstrated to date.

Stage of Development
Recent demonstrations include second-harmonic generation using ~50x less pulse energy than the previous state of the art, and multi-octave supercontinuum generation with ~500x less pulse energy than previous demonstrations in ion-exchanged waveguides with quadratic nonlinearities.