Ultraefficient on-chip supercontinuum generation: Bringing handheld sensing devices within reach

Truly portable supercontinuum sources with high spectral bandwidths are poised to advance applications such as medical imaging, chemical sensing, or light detection and ranging. Yet, limited efficiencies of conventional supercontinuum generation (SCG) schemes typically require relatively high pulse energies from bulky ultrafast lasers. We discuss a commercially emerging approach to SCG based on patterned sign-alternating dispersion (PSD) waveguide chips. It is based on alternately subjecting femtosecond seed laser pulses to normal and anomalous dispersion regimes in a highly controlled fashion. PSD waveguides decrease input power requirements down to factors on the order of 1/1000 as compared to other approaches and imply a disruptive reduction in power consumption, size, and costs of required seed laser light sources. We illustrate the real-world performance of PSD waveguide chips operating in tandem with ultra-compact femtosecond fiber lasers, and give an illustrative example of portable near-infrared absorption spectroscopy.