Study On Theory And Method Of Precision Measurement Based On Correlation Optics

Quantum Information Theory, born in80’s of the last century, experiencesa rapid development during the next three decades. Various schemes of quan-tum information processing has been proposed, and quantum information scienceconstantly improved and developed in many felds. These drive the relative ex-perimental techniques process. Among these quantum techniques, a variety ofquantum technology based on the optical system has been developed more fastcompared with other methods, because the light feld is easy for transport, andthe relatively mature photoelectron technology provides a necessary experimentalbasis for the preparing and testing of the non-classical light feld. In the processof its constant development, the correlation of the light feld has gradually at-tracted more and more attention, and shown unique advantages in measurementand imaging.The dissertation focuses on some hot issues associated with the applicationof the correlation of the light feld in measurement, mainly discusses the problemsof the generation of multi-photon NOON state and the optical gyroscope beyondshot-noise limit. Our works are as follows:1. The generation of multi-photon NOON state based on technology of cavityquantum electrodynamics Current theories and experiments have provedthat for phase measurement Heisenberg limit is the fundamental limit setby the quantum mechanics, while it can only reach the shot noise limit bythe traditional methods of measurement. And it is found that the feldin path-entangled Fock state, the so-called “NOON” state, can be appliedto achieved the Heisenberg limit measurement. However, the NOON stategenerated in present experiment condition contained a few photons, whichcan not meet the requirement of the practical measurement. How to prepare a NOON state contain large number of photons is a urgent problem to besolved. In the present thesis, two novel scheme for generating the opticalNOON state by the method of cavity QED technology have been proposed.(a) By using the atomic Bragg scattering with the cavity feld, a beamof atoms can be split coherently, and fy into two spatially separatedcavities, so that the entanglement between two spatial modes can beestablished. And then, through a stimulated Raman transition a op-tical Fock state is generated in either one of the two cavities. Conse-quently, the entangled optical Fock state between two spatial modesis obtained.(b) The refectance and the transmittance of a two-sided cavity will bemodulated by the interaction between the atom and the cavity. There-fore, a entangled light feld between two spatial modes can be preparedby using the interaction between a ladder-type three-level atom anda single-mode two-sided optical cavity. Then, the entangled feld isapplied to induce two atomic ensembles trapped in two spatially sep-arated cavities to emit photons, so that a multi-photon NOON stateis generated.2. Optical gyroscope with the light feld in two-mode squeezed coherent stateas light sourceIt has been proved by plenty theoretical and experimental studies that themeasurement limit of interferometry can be improved from the shot-noiselimit to Heisenberg limit, which means that the accuracy of the sensorsbased on interferometry can be further improved. For this reason, we in-vestigate the problem about how to improve the measurement accuracy ofthe phase-sensitive sensors, especially that of the phase-sensitive opticalgyroscope. From the perspective of the practical application, the light feldin the two-mode coherent state, which is rather strong in power and easy inpreparation, is adapted in our work. While, the method for measurementis still frst-order interferometry by measuring the intensity diference. Itshows that in this condition the sensitivity of the optical gyroscope not onlyis relative to the squeezing parameters, but also depends on phase of the amplitude of the initial coherent light feld used to prepare the two-modesqueezed light feld. Specifcally, when the light source is so-called twinbeam the sensitivity of the optical gyroscope will beyond the shot-noiseand shows great advantage in the signal-to-noise rate, the dynamic range,and so on. Compared with the classical optical gyroscope, the noise level isreduced greatly and the demand on the light source intensity is decreasedas well.3. Infuence of the noiseIn addition, we investigate the infuence of the noise in the source and in theprocess of optical transmission. On the one hand, we discuss the infuence ofthe intensity-diference and phase-diference of the two-mode squeezed lightfeld using as the source of the gyroscope. On the other hand, the infuenceof the noise in the light path, both commutative and non-commutative, isanalyzed in detail from the perspective of the energy loss.It shows that ina given condition, though the noise will cause a decrease in the sensitivityof the gyroscope the phase sensitivity below the shot-noise limit can still beachieved by increasing the squeezing parameter which decreases the photonstatistical noise, and then compensates the loss caused by other noise.