Quadratic Solitons: from Enhanced Sensing to Single-Cycle Pulses

Ultrashort optical pulses and their correspondingly broadband spectra have found myriad applications, including in sensing and spectroscopy, information processing, and extreme nonlinear optics. To date, quadratic nonlinear processes have been widely utilized in ultrafast optics, particularly in the important near- and mid-infrared spectral regions. Specific uses include broadband coherent up- and down-conversion with high efficiency, spectral broadening, short pulse amplification, and pulse characterization. With that said, experimental realizations of more complex nonlinear dynamical phenomena such as soliton formation in quadratic nonlinear systems have been limited, despite numerous theoretical proposals. Such phenomena can be accompanied by many practical benefits including pulse compression and improved conversion efficiencies, and their dynamics may be leveraged for applications such as sensing. Here, we discuss our recent experimental explorations of soliton formation and ultrashort pulse dynamics in both bulk and integrated quadratic nonlinear platforms. We emphasize specifically the new opportunities unlocked by moving to nanophotonics for entering previously unexplored dynamical regimes. Furthermore, we show how such processes may be leveraged for applications including molecular sensing, optical computing, and ultrashort pulse generation to the few- and single-cycle regime.

Short Bio

Robert Gray is a PhD candidate working in the Nonlinear Photonics Laboratory under Prof. Alireza Marandi at the California Institute of Technology in Pasadena, CA, USA. He received his Master of Science in Electrical Engineering from the California Institute of Technology in 2021 and his Bachelor of Science in Electrical Engineering and Applied Mathematics from Northwestern University in 2019.