Investigation On The Coherent Manipulation Of The Transverse Information Of Light Pulse In Solid

As human civilization enters the 21 st century, the traditional information technology is not able to satisfy the growing needs of people. With the appearance of quantum effects, people come to realize that developments in the field of quantum information will affect the progress of human civilization. The development in the field of quantum information is always inseparable from the quantum manipulation technology progress, and the understanding of the quantum storage also promotes the development in the field of quantum information. The construction of the quantum information network is the precondition of the quantum information age, how to realize the manipulation and storage of photons effectively is the foundation of quantum information networks. Because of its excellent properties, solid medium is more advantageous in the manipulation and storage experiment of light than gas medium, and also more suitable for constructing the quantum information network. For this reason, we finally choose the solid medium to carry out the investigation on the manipulation and storage of light. The main contents of my dissertation are as follows:1. We achieve the optical image information transfer and all-optical control based on the slow-light Four-wave Mixing(FWM) effect in the Pr:YSO crystal at low temperature.In this section we use a three-slit diaphragm to let the probe pulse carry the optical image information, and we make them induce the Electromagnetically Induced Transparency(EIT) in the Pr:YSO crystal through the probe pulse and control pulse. The optical image information has been slowed via the EIT effect in the crystal, and we obtain the slowed optical image information by a CCD sensor.When the probe pulse has been slowed, we add an extra control pulse to the EIT system in the crystal, by changing the parameters of this control pulse, a new information channel has been achieved via the slow-light FWM effect. We acquire the light pulse information in the new channel, and compare it with the light pulse information in the original channel, then we find that the optical image information in the two channels are basically identical. This experimental result shows that the slowed image information in the Pr:YSO crystal can be directly transferred between two information channels without light storage. Then we change the intensity of the extra control pulse, and we find that the image intensity in the new information channel has been increased with the increase of the extra control pulse intensity, but the image intensity in the original information channel has been decreased synchronously, it shows that we can control the direct transformation of the slowed image information between information channels for all-optical manipulation by changing the extra control pulse intensity. Finally, we also analyze the similarity between the images in two information channels, and we demonstrate that the adiabatic transfer and all-optical control of the slowed image information can always be maintained in a high similarity.2. We demonstrate that transverse spatial coherence of double light pulses can be preserved in the slow light storage process by using an EIT-driven solid, and the storage time cannot change the coherence-preserving.In this section, by changing the parameters of the control pulse and two probe pulses, we achieve the slow light effect of two probe pulses in the Pr:YSO crystal at low temperature at first, and then we make the probe pulses to form the Young-type spatial interference on the CCD sensor by controlling the light path. Through the interference pattern and the intensity distribution curve of the interference pattern, we’ve learned that the interference pattern of two slowed light pulses is basically the same as the Young-type spatial interference. After that by shutting off the control pulse adiabatically and turning it on again after a short period of time, the storage and the retrieve of two probe pulses in the crystal at low temperature are reallized. By changing the turn-off time of the control pulse, we get the interference pattern of the two retrieved pulses under different storage time, then through the data processing and analysis of the interference pattern, we further get the intensity distribution curve of the interference pattern in a horizontal direction and the interference visibility. From the comparison of the interference pattern, the intensity distribution curve and the interference visibility before and after the storage, we find that they are always highly consistent. It suggests that the storage process can not change the spatial interference pattern of two light pulses. Accordingly we demonstrate that the slowed light storage process based on EIT can preserve the transverse spatial coherence of the double light pulses, and the storage time cannot change the coherence-preserving of the double light pulses. At last, we study the interference visibility of two retrieved pulses with the change of storage time throughout the duration of storage. We find that the interference visibility is almost not changed with the storage time and kept in a high value. It suggests that the two retrieved pulses can always preserve a good state of interference during the whole storage process, the interference pattern has high identification and the experimental results have good accuracy. And also it suggests that the storage process and the storage time cannot change the transverse spatial coherence of double light pulses.There are two innovations in our investigation. One is realizing the transformation directly and all-optical manipulation of image information without storage process under the help of slow-light FWM effect. Another is proving that the transverse spatial coherence of light pulse can be preserved during the whole storage process, by the storage and retrieve of two probe pulses in the crystal at low temperature.In addition, we give an overall review on the history of the quantum information and the related field in the first chapter. In chapter two, we expound the basic theories involved in this dissertation, and also introduce the main instruments used in the experiments in detail. In the final chapter, we summarize the whole investigation and prospect the future of this research field.