**Nano-photonics** is the study of the behavior of light in micro-/nano-sized structures, often smaller than light wavelength.

In nano-photonic structures, light can be transferred, modified, absorbed, rotated, and newly generated. Due to the high refractive index contrast between silicon and cladding material, small volume of light confinement can be readily achieved with the advantages of

(1) Strong light-matter interactions inducing quantum/nonlinear optical behaviors,

(2) Minimization of an optical system,

(3) System stabilization due to monolithic on-chip optical systems,

(4) Scalability of the system.

In Shin Lab, we study novel physics due to dramatically enhanced nonlinear optical effects in such a small scale with following projects.

Correlated photon pairs can be generated through a silicon waveguide and silicon resonator by the spontaneous four-wave mixing process. The created photon pairs have non-classical states and can be used in quantum optics including quantum computing, quantum cryptography, and quantum metrology. We investigate efficient, small footprint, integrable, and scalable photon pair sources using optical fibers and silicon nano-structures.

*Quantum Photonic Integrated Circuits*

Quantum information processing requires the ‘*preparation*‘, ‘*manupulation*‘, and ‘*detection*‘ of Qubit (quantum bit: a unit of quantum information). To realize future quantum photonic technologies including photonic quantum computing, harnessing quantum photonic integrated circuits is practically necessary due to the functions of ‘minimization’, ‘stability’, and ‘scalability.’ In silicon photonics, we will integrate three parts of quantum photonic integrated circuits on a chip; quantum light source, linear photonic circuits, and single photon detectors for quantum information processing and quantum cryptography.

*Photon-phonon interaction (Optomechanics)
*

Light-matter interactions are dramatically enhanced in photonic nano-structures that lead to new physical phenomena or unprecedented performance. Phonon is the quantized energy of vibrational motion and its interaction with light is very week. With prudent design of the optomechanical structure, photons and phonons can be tightly confined to a small volume, strengthening the photon-phonon interaction and opening a new era of photonic signal processing including photonic RF fileters, sensors, silicon amplification / laser. We investigate the new physics and design of optomechanical systems.