Clément Javerzac-Galy

Mid-infrared ultra-high-Q resonators based on fluoride crystalline materials

The unavailability of highly transparent materials in the mid-infrared has been the main limitation in the development of ultra-sensitive molecular sensors or cavity-based spectroscopy applications. Whispering gallery mode microresonators have attained ultra-high-quality (Q) factor resonances in the near-infrared and visible. Here we report ultra-high Q factors in the mid-infrared using polished alkaline earth metal fluoride crystals. Using an uncoated chalcogenide tapered fibre as a high-ideality coupler in the mid-infrared, we study via cavity ringdown technique the losses of BaF2, CaF2, MgF2 and SrF2 microresonators. We show that MgF2 is limited by multiphonon absorption by studying the temperature dependence of the Q factor. In contrast, in SrF2 and BaF2 the lower multiphonon absorption leads to ultra-high Q factors at 4.5 μm. These values correspond to an optical finesse of , the highest value achieved for any type of mid-infrared resonator to date.

On-chip microwave-to-optical quantum coherent converter based on a superconducting resonator coupled to an electro-optic microresonator

We propose a device architecture capable of direct quantum electro-optical conversion of microwave to optical photons. The hybrid system consists of a planar superconducting microwave circuit coupled to an integrated whispering-gallery-mode microresonator made from an electro-optical material. We show that electro-optical (vacuum) coupling rates

Excitonic Emission of Monolayer Semiconductors Near-Field Coupled to High-Q Microresonators

g_0

Quantum cascade laser-based Kerr frequency comb generation

as large as

Quantum cascade laser Kerr frequency comb

\sim 2\pi \, \mathcal{O}(10-100)

Quantum cascade laser Kerr frequency comb generation

kHz are achievable with currently available technology, due to the small mode volume of the planar microwave resonator. Operating at millikelvin temperatures, such a converter would enable high-efficiency conversion of microwave to optical photons. We analyze the added noise, and show that maximum conversion efficiency is achieved for a multi-photon cooperativity of unity which can be reached with optical power as low as

Active photonic integrated circuits combining Si3N4 microresonators with 2D materials for applications in the visible wavelength range

\mathcal{O}(1)\,\mathrm{mW}

Excitonic emission of monolayer semiconductors near-field coupled to high-Q microresonators

.

High-Q optical microresonators functionalized with two-dimensional material

We present quantum yield measurements of single layer WSe2 (1L-WSe2) integrated with high-Q (Q > 106) optical microdisk cavities, using an efficient (η > 90%) near-field coupling scheme based on a tapered optical fiber. Coupling of the excitonic emission is achieved by placing 1L-WSe2 in the evanescent cavity field. This preserves the microresonator high intrinsic quality factor (Q > 106) below the bandgap of 1L-WSe2. The cavity quantum yield is QYc ≈ 10–3, consistent with operation in the broad emitter regime (i.e., the emission lifetime of 1L-WSe2 is significantly shorter than the bare cavity decay time). This scheme can serve as a precise measurement tool for the excitonic emission of layered materials into cavity modes, for both in plane and out of plane excitation.

Microwave to Optical Conversion Device and Method for Converting a Microwave Photon to an Optical Photon

We report mid-infrared Kerr comb generation based on a quantum cascade laser pumping a crystalline microresonator. For the first time QCL light is coupled into a microresonator via a tapered chalcogenide fiber allowing mid-IR Kerr comb generation.