arXiv subjects

Chee Fai Fong

Publications and source records attributed to Chee Fai Fong.

3 recordsLinked to original sources

arXiv2026

Photonic Waveguide Circuit Integrated with Carbon Nanotube Single-Photon Source Operating at Room Temperature

Photonic integrated circuits require robust room-temperature single-photon sources to enable scalable quantum technologies. Single-walled carbon nanotubes (CNTs), with their unique excitonic properties and chemical tunability, are attractive candidates, but their integration into photonic circuits remains challenging. In this work, we demonstrate the integration of functionalized CNTs as room-temperature single-photon emitters into photonic cavities and waveguide circuits. (6,5) CNTs with aryl sp$^3$ defects are either stochastically deposited via drop-casting or deterministically positioned on photonic cavities using an anthracene-assisted transfer method guided by real-time photoluminescence monitoring. Photoluminescence spectra reveal cavity-enhanced emission, while second-order autocorrelation measurements confirm single-photon propagation through the photonic integrated circuit, highlighting the potential of CNTs for scalable, room-temperature quantum photonic applications.

physics.optics↗

arXiv2023

Van der Waals functionalization of ultrahigh-Q silica microcavities for $χ^{(2)}$-$χ^{(3)}$ hybrid nonlinear photonics

Optical nonlinear processes are indispensable in a wide range of applications including ultrafast laser sources, microscopy, metrology, and quantum information technologies. Combinations of the diverse nonlinear processes should further lead to the development of unique functionalities, but simultaneous use of second- and third-order nonlinear processes is generally difficult. Second-order effects usually overwhelm the higher-order ones, except in centrosymmetric systems where the second-order susceptibility vanishes to allow the use of the third-order nonlinearity. Here we demonstrate a hybrid photonic platform whereby the balance between second- and third-order susceptibilities can be tuned flexibly. Ultrahigh-Q silica microcavities capable of generating third-order effects are functionalized by atomically thin tungsten diselenide, and we observe cavity-enhanced second-harmonic generation and sum-frequency generation with continuous-wave excitation at a power level of only a few hundred microwatts. Pump power dependence exhibits drastic increase and saturation of the second-harmonic light, originating from the dynamic phase-matching process. We show that the coexistence of second- and third-order nonlinearities in a single device can be achieved by carefully choosing the size and the location of the two-dimensional material. Our approach can be generalized to other types of cavities, unlocking the potential of hybrid systems with controlled nonlinear susceptibilities for novel applications.

physics.optics↗

arXiv2018

Scheme for media conversion between electronic spin and photonic orbital angular momentum based on photonic nanocavity

Light with nonzero orbital angular momentum (OAM) or twisted light is promising for quantum communication applications such as OAM-entangled photonic qubits. There exist photonic OAM to photonic spin angular momentum (SAM), as well as photonic SAM to electronic SAM interfaces but not any direct photonic OAM-electronic SAM (flying to stationary) media converter within a single device. Here, we propose a scheme which converts photonic OAM to electronic SAM and vice versa within a single nanophotonic device. We employed a photonic crystal nanocavity with an embedded quantum dot (QD) which confines an electron spin as a stationary qubit. Spin polarized emission from the QD drive the rotation of the nanocavity modes via the strong optical spin-orbit interaction. The rotating modes then radiate light with nonzero OAM, allowing this device to serve as a transmitter. As this can be a unitary process, the time-reversed case enables the device to function as a receiver. This scheme could be generalized to other systems of resonator and quantum emitters such as a microdisk and defects in diamond for example. Our scheme shows the potential for realizing an (ultra)compact electronic SAM-photonic OAM interface to accommodate OAM as an additional degree of freedom for quantum information purposes.

cond-mat.mes-hall↗