Photon-blockade Effect Of A Hybrid System Consisting Of An Optomechanics Coupled To A Two-level System

The control of photons is a foundamental and vital topic in quantum optics. In cav-ity optomechanical systems, many interesting phenomena can be observed by means of control of photons. Owing to its unique formation of light-matter interaction, which of-ten connects to the coupling between cavity field and mechanical modes, photon blockade effect, photon sideband effect, nonlinear optomechanical induced transparency and other unusual effects have been widely investigated. Recently, the coupling of hybrid system composed of cavity-optomechanical subsystems to other quantum systems attracts scien-tists’attentions and provides a new method to study the valuable quantum phenomena and optical effects. The results support a global view of quantum optics, especially in nonlinear effects of cavity optomechanics.In this thesis, we investigate the photon blockade effect in the system consisted by a standard cavity optomechanics and a two-level atom, where the atom couples to light-cavity, and the cavity mode interacts with an end mirror (also called mechanical res-onator). The cavity and the atom are simultaneously driven by a weak coherent field. The Schrodinger equation has been used in the derivation of amplitudes, and by transform-ing the Hamiltonian into dressed state, the relevant master equation can be obtained. Then both the numerical and analytical calculations have been done to show how the parameters of the system modulate the photon blockade effect. It is shown that when parameters are optimized, two-photon transition will be deeply suppressed and only single-photon transi-tion takes place. The reason lies in destructive interference of different transition channels in dressed state, which can be realized in accordance to the medium coupling strength that has been chosen. Additionally, the corresponding second order correlations has been inves-tigated, including cavity, mechanical resonator and the cross second order correlations of cavity-resonator. We’ve mainly studied the influence of driving field intensity and phase, coupling strength on photon blockade of quantum interference and some other nonclassical effects of the hybrid system via plots of those correlation functions. The sub-poissonian statistical distributions have been observed, which revealed the system’s nonclassical prop-erties and verified the quantum interference process.