[EQuAL] Singly Resonant InGaP Microresonators for Efficient, Low-Threshold Second-Order Nonlinear Optics

Speaker: Yiming Pang

Title: “Singly Resonant InGaP Microresonators for Efficient, Low-Threshold Second-Order Nonlinear Optics”

Abstract:

Strong 𝜒⁽²⁾ interactions at low optical powers are key to scalable nonlinear and quantum photonics. Doubly resonant microresonators exhibit exceptional efficiencies but require simultaneous resonance and phase-matching of widely separated optical frequencies, making them inherently sensitive to fabrication and operating conditions. Singly resonant cavities eliminate this constraint by resonating at only the fundamental frequency while the second-harmonic field propagates in a single pass, but they have traditionally sacrificed nonlinear efficiency. Here, we demonstrate a singly resonant InGaP-on-insulator microresonator that overcomes this trade-off. Combining the large 𝜒⁽²⁾ nonlinearity of InGaP with high-quality-factor resonators, we achieve efficient and widely tunable second-harmonic generation, broadband quantum-frequency-comb generation, and low-threshold optical parametric oscillation. Unlike conventional centimeter-long singly resonant devices, our millimeter-scale InGaP devices deliver nonlinear performance comparable to, and even exceeding, doubly resonant systems. By overcoming the conventional efficiency-robustness trade-off of singly resonant devices, this work opens a new route to low-power, broadband, and widely tunable 𝜒⁽²⁾ nonlinear and quantum photonics.

The Exploring Quantum Assembly at Lunch (EQuAL) seminar is jointly funded by the Eddleman Quantum Institute, the InTriQATe NSF Research Traineeship (NRT), and the Quantum Foundry.

Fall quarter 2026 is generously funded by the InTriQATe NRT.

The Integrative Training in Quantum Assembly and Technology (InTriQATe) NSF Research Traineeship (NRT) aims to support and inspire the next generation of quantum scientists by providing innovative opportunities for training and professional development in an interdisciplinary collaborative context.