Preparation Of Anti-Bunching Quantum Photon/Phonon Source Based On Photon/Phonon Blockade Effect

In recent years,with the development of quantum science and technology as one of the important scientific and technological projects of national strategic intention,the development of quantum technology in China has been paid more and more attention.Quantum technology covers a wide range of fields,including quantum computing,quantum precision measurement,quantum communication,quantum sensing and quantum cryptography.Bright and pure antibunching quantum light/sound source is one of the key quantum devices to realize most quantum technologies such as quantum computing and quantum communication.The photon/phonon blockade effect is an important means to prepare the antibunching quantum light/acoustic source.Based on the importance of antibunching quantum light/sound source to quantum technology,this paper mainly designs antibunching quantum light/sound source through photon/phonon blockade effect.In this thesis,we study the photon/phonon blockade in three different quantum optical systems.In Sec.2,photon blockade in a coupled-cavity system consisting of two Kerr nonlinear cavities is studied.The physical mechanism of the photon antibunching in the coupled-cavity system is explained based on the eigen energy spectrum,and it is found that the quantum interference in the unconventional photon blockade can enhance the photon antibunching effect.The results show that the system can output antibunched photons with high purity and brightness.In Sec.3,two-photon excitation of a quantum dot placed in an optical microcavity is used to generate antibunched entangled photons.We find that the entangled photon pairs mainly come from the cascade radiation from the triplet state to the ground state in the dressed state of the system.This scheme eliminates the unentangled photon pairs produced by single cascade radiation in the traditional scheme.We find that the entangled photon pairs are anti-bunched due to the photon blockade effect.This indicates that our system can efficiently generate anti-bunched entangled photon pairs.In Sec.4,due to the unique advantages of phonons in solid-state quantum information processing systems,the preparation of single-phonon sources has attracted much attention.In this part,we study the phonon blockade effect in the full acoustic system consisting of a parametrically driven nanomechanical oscillator at finite temperature.In contrast to other phonon blockade schemes,our scheme does not require the mechanical oscillator to have an intrinsic nonlinearity or an auxiliary nonlinear system.In addition,the statistical properties of phonons at finite temperature are studied by using the Monte Carlo wave function method.Since there is no auxiliary system,the time-dependent second-order correlation function curve of the acoustic field does not oscillate,which is beneficial to the generation of single phonons under pulse excitation.