摘要
微腔激子极化激元由于具有较轻的有效质量,很容易实现玻色-爱因斯坦凝聚(Bose-Einstein condensate,BEC),其在外界驱动下产生的陀螺效应具有广阔的应用前景.本文研究了微腔激子极化激元在环形光束泵浦下微腔半径以及泵浦参数对体系演化的影响.从单分量的Gross-Pitaevskii方程出发,对环形微腔中的激子极化激元BEC体系的演化过程进行研究.通过数值模拟研究了在环形微腔中保持体系稳定演化的最大涡旋叠加态花瓣数与微腔半径的关系,分析了不同形式的环形光束泵浦作用下激子极化激元体系的演化情况,发现在微米量级的微腔半径下,特定形式的单环泵浦和多环泵浦能够使得微腔容纳更高阶的激子极化激元稳定涡旋叠加态的存在.研究结果表明,在一定的泵浦驱动条件下,微腔半径的大小与体系能容纳的涡旋叠加态花瓣数上限之间是线性正相关的,并且在改变泵浦激光构型时能够突破这一上限,产生高阶、多重的涡旋叠加态.
Owing to its light effective mass, polariton can easily realize Bose-Einstein condensates(BEC) and can also produce gyro effect under external drive. Therefore, it has a promising application prospect. Based on the Gross-Pitaevskii equation, the evolution of the exciton polaron BEC system in the annular microcavity is studied. Two key parameters affecting the characteristics of the exciton polaron system, namely the size of the microcavity and the configuration of the ring-shaped pumped beam, are investigated. The size of microcavity often directly affects the volume and power consumption of integrated devices. In addition, the number of coherent petals of exciton polariton superposition state matter wave propagated in microcavity is closely related to the precision and sensitivity of gyro, and the size of microcavity has a direct effect on the number of coherent petals. At the same time, whether the pumping region is continuous or not also has a key effect on the evolution of the system, and different pump configurations will affect the evolutions of the system. We find that in the microcavity radius on a micron scale, the annular microcavity can excite the petal of vortex superposition state when pumped by pumping light, and the petals can be stable, but circular cavity with a certain radius can“accommodate” a limited vortex quantum number, when vortex quantum number is too large, the system will be unstable and unable to support the formation of stable petals. However, with the increase of the radius of the annular microcavity, the superposition petal number of the exciton polariton system contained in the annular region will also increase, and the maximum petal number contained in the exciton polariton system has a positive linear correlation with the inner radius of the annular microcavity. At the same time, we find that when the pump laser configuration is changed, the system will evolve into a special form of steady state. The calculation results show that when microcavity parameters are the same but for only changing the radial width of single pump, the number of petals obtained is three times that before changing the radial width. In such a case, the number of superposition petals not only exceeds the previously calculated maximum number of petals accommodated by the annular cavity under the radius but also there appear the multiple petals combined radially. Under the double-ring pump system, changing the width of the hollow ring may produce not only the new exciton polariton condensation in the hollow ring, but also vortex states in the original petal. Under each of the three-ring and four-ring pumping condition, the evolution of the system finally presents a multi-petal state in the radial direction. Because these vortex superposition states contain the information about the density and the phase, it has important guiding significance for designing the new system of gyroscope. Therefore, these special evolutionary results open a new direction for studying the new system gyroscope.
作者
熊振宇
蔡远文
吴昊
刘通
刘政良
任元
Xiong Zhen-Yu;Cai Yuan-Wen;Wu Hao;Liu Tong;Liu Zheng-Liang;Ren Yuan(Department of Aerospace Science and Technology,Space Engineering University,Beijing 101400,China;Laboratory of Quantum Detection&Awareness,Space Engineering University,Beijing 101400,China;State Key Laboratory for Laser Propulsion and its Applications,Space Engineering University,Beijing 101400,China)
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2021年第24期53-61,共9页
Acta Physica Sinica
基金
国防科技创新特区项目、国家自然科学基金(批准号:11772001,61805283)
北京市青年拔尖人才支持计划(批准号:2017000026833ZK23)资助的课题.
