Broadband infrared spectroscopy using optical parametric oscillation in a radially-poled whispering gallery resonator

Abstract

We demonstrate optical parametric oscillation in a millimeter-sized whispering gallery resonator suitable for broadband infrared spectroscopy. This nonlinear-optical process is quasi-phase-matched using a radial domain pattern with 30 µm period length, inscribed by calligraphic poling. The output wavelengths are selected in a controlled way over hundreds of nanometers. We achieve this by increasing the temperature of the resonator in steps such that the azimuthal mode number of the pump wave rises by one. As a proof-of-principle experiment, we measure a characteristic resonance of polystyrene in the spectral range of 2.25 - 2.45 µm.

Three‐wave mixing in whispering gallery resonators

“…Here, poling conditions like voltage or speed of the tip can be easily adopted to the writing direction. Such an optimization leads to radial patterns with almost uniform domains (Fig. d).…”

Nonlinear and Quantum Optics with Whispering Gallery Resonators

“…Since then, several lithography-based radial poling techniques have been developed [324] specifically for WGM resonators, including the already mentioned calligraphic poling technique [216,217].…”

On-chip χ(2) microring optical parametric oscillator

“…Radially or linearly poling these devices further enabled tunable quasi-phase-matching beyond 2 µm wavelengths with in-resonator OPO conversion efficiencies near 50% [21][22][23][24][25]. Recent work has employed OPOs for high resolution spectroscopy in the mid-infrared regime [26,27] and has extended the wavelength of the idler waves beyond 8 µm using novel materials such as AgGaSe 2 and CdSiP 2 [28,29].…”