The Research And Application Of Spectral Hole Burning Based On Optical Bloch Equations

Radar signal or ultra-wideband RF spectrum analysis needs very sensitive processingtechniques in order to analyze signals spanning several gigahertz of bandwidth undermilliseconds. Spectral hole burning technology meet the above requirements by using thecrystal’s inhomogenously broadend of dozons GHz and homogenously broadend hundreds ofKHz, which has overcame the drawbacks of traditionally electrical techniques, become one ofthe hot issues of the research.In this letter, the characteristics of spectral-hole-burning in Tm3+: YAG crystal based onthe optical Bloch equations has been studied. The influence of optical length on spectral holedepth within cryogenic temperature range is analyzed, and the influence of laser intensity onthe spectral hole depth and width are investigated. The main work is as follows:1. A novel model is proposed to analyze the spectral hole depth dependence on opticallength within cryogenic temperature range. By using the proposed model, the maximumspectral hole depth can be found by choosing the optimum optical length. Based on the opticalBloch equations, the absorption coefficient has been derived, then we theoretically deduce thespectral hole depth dependence on optical length on. The simulations reveal that the readoutspectral hole depth increase to maximum and then decrease with the increasing temperature,the maximum spectral hole depth can be found by choosing the optimum optical length.2. Based on the established model of spectral-hole-burning characteristics of Tm3+: YAGcrystal, the dynamic process of spectral hole depth and width with the write laser intensity isderived. According to the simulation results, it can be known that the write intensity and theengraving time are equivalent to spectral hole depth and width, spectral hole characteristicsarise with the engraving power.