Studies On Coherent Control And Potential Applications Of Double-cavity Optomechanical Systems

With the continuous development of advanced material manufacturing techniques,the spatial scale of optomechanical devices is getting smaller and smaller. Theoptomechanical systems have developed toward micro size so that the high-finesseoptical micro-cavity emerged. Although they are in micron scale, significant quantumoptomechanical effects will emerge when they interact with lasers because theirmasses are very tiny. Quantum optomechanics not only verifies the fundamentaltheorem of quantum mechanics, but also has extremely extensive applicationprospects. On the one side, it provides new methods for high-precision measurementto feeble forces, masses, displacement and for observing quantum movement ofmacroscopic objects. For example, people have applied the gravitational wavedetector to detect gravitational waves. On the other hand, cavity optomechanicspromises to detect and manipulate mechanical motion in the quantum regime usinglight and to create nonclassical states of light and mechanical motion, such asentangled states and squeezed states. These states can be used to the quantuminformation processing where the optomechanical devices can serve as coherentlight-matter interfaces. In addition, it offers a route towards fundamental tests ofquantum mechanics in a hitherto unapproachable parameter regime of mass and size.In this dissertation, we study the coherent phenomena and relevant efficient dynamiccontrol about optomechanically induced transparency, coherent perfect absorption,coherent perfect transmission in double-cavity optomechanical system.First, we study a double-cavity optomechanical system in which a movablemembrane with perfect reflection is inserted between two fixed mirrors with partialtransmission. The system is driven by a coupling field and a probe field from theleft-hand side while only one driving field from the right-hand side. We find theintensity of the right driving field has important influences on the absorption and dispersion properties of the probe field. If turning off the right-hand driving field andthe system is under the resolved mechanical red sideband, the standardoptomechanically induced transparency in the one-cavity optomechanical system willemerge. But when we turn on the right-hand driving field under the same resolvedmechanical red sideband, the depth of the transparency window will becomeshallower as the strength of the right-hand driving field becomes stronger. Thetransparency window will disappear when the intensity of the right-hand driving fieldis about three times the intensity of the left-hand coupling field. Then we canmanipulate the probe to transfer between absorption state and transparency state torealize the optomechanical all-optical switch through adjusting the intensity of theright-hand driving field. We also study the nonlinear normal mode splitting processesin this model. We find the intensity of the right driving field has important influenceson the critical power above which the system will work from the optomechanicallyinduced transparency parameter regime to the normal mode splitting parameterregime. More importantly, on the condition that the intensity of the left driving fieldremains constant, the critical power will decrease along with the increasing intensityof the right driving field. Then we can effectively control the critical power just byadjusting the intensity of the right driving field, realizing that the system convertsfrom the optomechanically induced transparency parameter regime to the normalmode splitting parameter regime. We also find the intensity of the right driving fieldhas important influences on properties of the Stokes and the Anti-Stokes processes,especially when the intensities of the two strong fields equal, the output power of theleft-hand Stokes field is almost zero. It means the system absorbs almost the energy ofthe probe field. While the output power of the Anti-Stokes field reduces as theintensity of the right-hand driving field increases.Secondly, we study another important case when the optomechanical system isdriven from both fixed end mirrors in a symmetric scheme by two strong couplingfields and two weak probe fields for the same “Fixed Mirror-Movable Membrane-Fixed Mirror” optomechanical structure. We find the relative intensity of the twocoupling fields and the relative phase of the two probe fields will have an important effect on the absorption and transmission of the two probe fields due to the effect ofnonlinear light pressure. Our study shows the interesting quantum coherentphenomena about coherent perfect absorption and coherent perfect transmission willemerge if the relative intensity of the two coupling fields, the relative phase of the twoprobe fields and the damping rate of mechanical oscillator are under some certainconditions. It needs to be pointed out that the above quantum coherent phenomenawill appear only for the specific frequency probe field when the system parametersare specified as certain fixed values. In addition, if we want the perfectoptomechanically induced transparency appears on one side, there must be anotherprobe field inputted on the other side with out of phase, and the two probe fieldsintensity ratio must be consistent with the two corresponding coupling fields intensityratio. The width of the transparency window will become wider as the intensity ratioincreases. Therefore we can effectively control the depth and width of thetransparency through adjusting the relative intensity of the two coupling fields and therelative phase of the two probe fields. In conclusion, we can control the dynamicalpropagation characteristics of the probe field in the system, which is very important inquantum information processing, such as for realizing all-optical switch, light router.At last, we give a concise summery about this dissertation, and moreover, wepropose an outlook for our further work. The current thesis wish to provide a new wayto realize the quantum devices such as all-optical switch and light router in quantuminformation processing.