微纳光机械系统的量子动力学研究

发布时间：2019-04-08 15:18

【摘要】：最近几年，光学腔和机械系统的耦合引起了人们的广泛关注，由一个光学谐振腔和一个机械振子构成的腔光机械系统更是成为了一个新的研究热点。最近，光机械系统中的强耦合效应，光机械冷却，以及系统中类似于电磁诱导透明的现象被实验证实，为将来的量子通讯、信息传输等应用开辟了道路。本文中所研究的光机械系统即是光学自由度和机械自由度相耦合的系统。本文中，通过求解海森堡运动方程，我们研究了三种典型光机械系统中的光机械动力学行为，研究内容与结论如下：（1）研究由辐射压力与驱动Fabry-Perot光学腔相耦合而产生的腔光机械动力学行为。发现随着输入激光功率的增加，振子的涨落光谱呈现简正模式分裂的现象。同时推导了有效机械阻尼和共振频移。此外引入一种近似机制来研究振子的基态冷却，，并且考虑在解析边带机制下简正模式分裂对机械振子冷却影响。最后数值讨论初始浴温度、输入激光功率和机械品质因数这三个因素对机械振子冷却的影响。结果表明在低初始温度、高输入激光功率和高机械品质因数条件下，光机械振子可以被冷却到基态。（2）在Fabry-Perot光机械腔中,从光机械系统的哈密顿量出发，探讨在失谐的条件下光机械腔中的量子现象。引入散射矩阵方案来论证光子和声子以有效并且可逆的方式转换。这对于光学光子和微机械阵子之间的量子态的转变提供了一个可行的方案。光声转变预示着一种可行的量子光学器件。同时用量子愞之万方法和主方程途径这两种方法推导最终声子占有数来研究基态冷却，并且对这两种方法进行了参数比较。得出当机械品质因数不是很大、初始浴温度较高和输入激光功率较大时，用量子愞之万方法得到的机械振子的冷却要比用主方程途径得到的结果要好。（3）我们通过线性化量子郎之万方程研究了一维传输线共振器和Fabry-Perot光机械腔中的简正模式分裂和冷却，并对这两种光机械系统做了比较。在低初始温度和高品质因数下振子可以被冷却。考虑到机械振子的尺寸和与预冷却技术，传输线共振器比光学腔较容易实现基态冷却。（4）我们设计了一种回音壁腔光机械系统，研究了失谐回音壁腔中的光机械动力学行为。在单模腔光机械系统中，腔透射和反射呈现“M”和“W”形状模式分裂。当同时存在探测光和控制光的时，探测场呈现类似于电磁诱导透明的现象。我们的结果证明可以通过光机械系统来实现相干操纵光而不需要原子共振来实现共振干涉。然而由于光的剩余散射导致腔中出现一对驻波模，此时透射和反射呈现三模分裂。通过操纵回音壁光机械系统使光学处理成为可能，而延迟、减慢和存储光脉冲可以通过光机械器件来实现。同时拓宽了光机械系统在光学通讯和量子信息处理方面上的应用。
[Abstract]:In recent years, the coupling of optical cavity and mechanical system has attracted more and more attention, and the optical mechanical system composed of an optical resonant cavity and a mechanical oscillator has become a new research hotspot. Recently, the strong coupling effect, optical mechanical cooling and electromagnetically induced transparency in optical mechanical systems have been proved by experiments, which have opened the way for future applications such as quantum communication and information transmission. The optical mechanical system studied in this paper is a coupling system of optical degrees of freedom and mechanical degrees of freedom. In this paper, by solving the Heisenberg equation of motion, we study the photomechanical dynamic behavior in three typical photomechanical systems. The research contents and conclusions are as follows: (1) the photomechanical behavior of the cavity induced by the coupling of radiation pressure and driving Fabry-Perot optical cavity is studied. It is found that with the increase of the input laser power, the fluctuation spectra of the oscillator show the phenomenon of normal mode splitting. At the same time, the effective mechanical damping and resonance frequency shift are derived. In addition, an approximate mechanism is introduced to study the ground state cooling of the oscillator, and the effect of normal mode splitting on the cooling of the mechanical oscillator is considered under the analytical sideband mechanism. Finally, the effects of initial bath temperature, input laser power and mechanical quality factor on the cooling of mechanical oscillator are discussed numerically. The results show that under the conditions of low initial temperature, high input laser power and high mechanical quality factor, the photomechanical oscillator can be cooled to the ground state. (2) from the Hamiltonian of the optical mechanical system in the Fabry-Perot optical mechanical cavity, the quantum phenomena in the optical mechanical cavity are discussed under the condition of detuning. The scattering matrix scheme is introduced to demonstrate that photons and phonons are converted in an efficient and reversible manner. This provides a feasible scheme for the transition of quantum states between optical photons and micromachined arrays. The photoacoustic transition indicates a feasible quantum optical device. At the same time, the quantum method and the master equation approach are used to derive the final phonon possession number to study the ground state cooling, and the parameters of the two methods are compared. It is concluded that when the mechanical quality factor is not very large, the initial bath temperature is high and the input laser power is large, the cooling of the mechanical oscillator obtained by the quantum method is better than that obtained by the master equation. (3) We study the normal mode splitting and cooling in one-dimensional transmission line resonator and Fabry-Perot optical mechanical cavity by linearizing the quantum Langevin equation, and compare the two optical mechanical systems. The oscillator can be cooled at low initial temperature and high quality factor. Considering the size of the mechanical oscillator and the pre-cooling technology, the ground state cooling of the transmission line resonator is easier than that of the optical cavity. (4) We design a kind of photomechanical system of echo wall cavity, and study the photomechanical dynamic behavior of detuning echo wall cavity. In the single-mode cavity optical mechanical system, the cavity transmission and reflection show "M" and "W" shape mode splitting. When both probe light and control light exist, the detection field is similar to electromagnetically induced transparency. Our results show that coherent manipulation of light can be achieved by optical mechanical systems without the need for atomic resonance to achieve resonance interference. However, due to the residual scattering of light, a pair of standing wave modes appear in the cavity, and the transmission and reflection present three-mode splitting. Optical processing is possible by manipulating the echo wall photomechanical system, while delay, deceleration and storage of optical pulses can be achieved by optical mechanical devices. At the same time, the application of optical mechanical system in optical communication and quantum information processing is broadened.
【学位授予单位】：吉首大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TH113

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