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arXiv · 2510.05636

Broadband spectral mapping of photo-induced second-harmonic generation in silicon nitride microresonators

Ji Zhou·Marco Clementi·Samantha Sbarra·Ozan Yakar·Camille-Sophie Brès
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Abstract

By employing a pump-probe technique for enhanced spectral mapping of the dynamics in nonlinear frequency conversion, we demonstrate that photo-induced second-harmonic generation (SHG) in silicon nitride (Si3N4) microresonators can persist when transitioning from the preferred doubly resonant condition--where the resonances of the optical harmonics are required to be matched--to a highly detuned state where the generated second harmonic is significantly shifted away from its corresponding resonance. This results in an unconventionally broad conversion bandwidth. Other intriguing phenomena, such as detuning-dependent all-optical poling and nonlinear multi-mode interaction, are also presented for the first time with direct experimental evidence. Our findings provide new insights into the physics of photo-induced second-order (\chi^{(2)}) nonlinearity, highlighting its potential applications for nonlinear \chi^{(2)} photonics in integrated Si3N4 platform

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Ji Zhou, Marco Clementi, Samantha Sbarra, Ozan Yakar, Camille-Sophie Brès. 2025-10-07. Broadband spectral mapping of photo-induced second-harmonic generation in silicon nitride microresonators. https://arxiv.org/abs/2510.05636

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