Study On The Generation Process Of Photon Echo With Controlled Pulses

Photon echo is a transient coherent optical phenomenon that has received widespread attention since its discovery.With the development of the photon echo technology,its applications in signal processing,signal storage,and arbitrary signal generation have gradually matured,and it also makes the research on photon echoes more urgent.By analyzing and researching the photon echo generation model,researchers can have more ways and use more parameters to precisely control the performance of the echo in order to improve its application performance.Therefore,accurately grasping the relevant characteristics of photon echoes is the basis for carrying out research in its application field,the study of photon echo generation process is of great significance.The main work of this article includes:1.The research background of the study of photon echo and its research status are summarized.The derivation process of the optical Bloch equation is given based on the density matrix method.The relationship between Maxwell wave equation and Bloch equation is established,and the Maxwell-Bloch coupled transmission equation is derived.Finally,the vector interpretation of the photon echo is given.2.We investigate the performance of the induced double-amplitude population grating(DAPG)based on spatially periodic modulation by the optical non-overlapping interaction of unipolar pulses.Considering the two typical allowed pulse configurations,the time delay requirements and the relationship between the grating amplitude,phase shift and the time delay were analyzed in detail.The results reveal that the grating amplitudes and phase can be dynamically controlled by the suitable time delay between the excited pulses.The population gratings presented here maybe offer more potential applications in the study of photon echo characteristics and in nonlinear optics.3.The different responses of the shape of two-pulse photon echo and three-pulse to different excitation pulse areas and the time offset relative to the expected arrival time of the echo are analyzed and explained theoretically.The varying pulse area by varying pulse width and electric field intensity may show complex echo shapes.Based on two different echo types,the time offsets of echo signals with three different pulse widths are also studied.The results show that the larger the pulse width,the greater the offset of the echo,and the advance and delay of the echo will appear with the change of the excitation pulse area.