Research On The Solution And Application Of Optical Bloch Equation With Phase Term

In the research of the interaction between light and matter,the motion state of the atom can be characterized by the in-phase component u,the in-quadrature component v and the number of atoms wof the Bloch equation.Based on this,the corresponding physical phenomena caused can be studied,such as spectral hole burning,photon echo.In the reported paper on the research of phenomenon of light-matter interaction based on optical Bloch equation,the effect of the amplitude of incident field on the atom has been thoroughly discussed,but the effect of the phase of the incident field is not considered.Based on these,the main content of this thesis are as follows.1.Firstly,Bloch equation with phase term is deduced with the slow varying envelope and rotating wave approximation,and the steady state solution of Bloch equation with phase is also obtained.Secondly,starting with Maxwell wave equation,the propagation equation is deduced with the bond for macro polarization.2.Starting with the w of Bloch components,the expression of absorption coefficient is deduced under the condition of steady-state,and the application of spectral hole burning phenomenon for the detection of signal power spectrum is also briefly introduced.Further more,when crystal with hole burning is as a filter,the effect of write pulse’s intensity and crystal properties on the performance of the filter was studied.3.Starting with the in-phase uand in-quadrature vof Bloch components,the influence of the phase of the incident field on the crystal particles is studied under the condition of steady-state.Based on this,the vector induced electric field generated by the macroscopic polarization is discussed in detail,and the relationship between the vector induced electric field and the traditional macroscopic polarized radiation field is clarified.Based on the analysis of the expression of vector induced electric field components,a theoretical method for static relative phase measurement of incident signals under steady-state condition is obtained.Meanwhile,the influence of minimum interval between different frequency channels and additive Gauss noise on the phase measurement accuracy is analyzed.4.Numerical solution of optical Bloch equation with phase is obtained by applying fourth Runge-Kutta.Furthermore,the time range of the stimulated atom reached quasi steady state was obtained which is about10T₂by the change trend of Bloch components for first time.Based on the discussion of fourth chapter,the time varying phase function which is time step change with10T₂ as the basic unit can be measured.At the same time,the sensitivity of real time phase measurement and the influence of additive Gauss noise on the phase measurement accuracy are also analyzed.