Nonlinear and Quantum Optics with Whispering Gallery Resonators

Abstract

Optical whispering gallery modes (WGMs) derive their name from a famous acoustic phenomenon of guiding a wave by a curved boundary observed nearly a century ago. This phenomenon has a rather general nature, equally applicable to sound and all other waves. It enables resonators of unique properties attractive both in science and engineering. Very high quality factors of optical WGM resonators persisting in a wide wavelength range spanning from radio frequencies to ultraviolet light, their small mode volume, and tunable in-and out-coupling make them exceptionally efficient for nonlinear optical applications. Nonlinear optics facilitates interaction of photons with each other and with other physical systems, and is of prime importance in quantum optics. In this paper we review numerous applications of WGM resonators in nonlinear and quantum optics. We outline the current areas of interest, summarize progress, highlight difficulties, and discuss possible future development trends in these areas.

Two-color flat-top solitonic pulses in χ(2) optical microresonators via second-harmonic generation

“…In contrast with Kerr microresonators, in χ (2) microresonators platicon generation takes place on both sides of the linear microresonator resonance and upon both forward and backward frequency scans (see upper panels in Fig. 3).…”

“…However, those works only predict that the solitonic solutions exist, but do not show how they can be actually generated under realistic experimental conditions. In our work we demonstrated numerically for the first time that applying the methods developed for the platicon generation in Kerr microresonators [33][34][35][36], we can obtain the generation of the two-color flat-top solitonic pulses, platicons, in χ (2) optical microresonators. Platicon excitation was observed for both combinations of the GVD coefficients with the opposite signs.…”

“…Platicon generation processes were simulated numerically, excitation conditions and platicon generation domains were found for different generation methods, and the properties of generated platicons were studied for the different combinations of the medium parameters.During the last decade generation of Kerr frequency combs was demonstrated in high-Q microresonators of different geometries, bulk, and on-chip, made of different materials (crystalline fluorides, diamond, quartz, silicon, silicon nitride, etc.) [1][2][3][4]. Coherent microresonator-based frequency combs or dissipative Kerr solitons [5,6] were found to be an efficient tool for various important applications, such as metrology [7,8], spectroscopy [9,10], astrophysics [11,12], high volume telecommunications [13].…”

“…parametric oscillators [2,[21][22][23][24][25][26][27][28][29][30]. Generation of optical frequency combs due to the quadratic nonlinearity may be realized at reduced pump powers because of the high level of nonlinear response and in spectral diapasons inaccessible for conventional Kerr frequency combs.…”

Selective Coupling Enhances Harmonic Generation of Whispering-Gallery Modes

“…WGM resonators are natural vessels to study nonlinear effects due to an unparalleled combination of favorable characteristics [6,7]. The method of entrapment is total internal reflection, which allows for very good spatial confinement along the rim of the resonator.…”