The estimation of the phase difference of two vibration signals of the same frequency by cross - spectral density 用互譜密度函數(shù)估算兩同頻振動(dòng)信號(hào)的相位差
The basic concepts of second - order coherence theory in describing wavefields are introduced . these concepts are the cross - spectral density function and spectral degree of coherence in the space - frequency domain , and the mutual coherence function and the complex degree of coherence in the space - time domain 介紹了二階相關(guān)理論中描述光場相干性質(zhì)的基本概念,包括空間-時(shí)間域中的互相關(guān)函數(shù)、復(fù)相干度和空間-頻率域中的交叉譜密度函數(shù)、光譜相干度。
Based on the propagation law of the cross - spectral density function in the space - frequency domain , the properties of polychromatic vector gsm beams through a paraxial optical abcd system are studied . the analytical propagation expressions for the cross - spectral density matrix of vector gsm beams passing through a paraxial optical abcd system are derived , which permits us to study the propagation properties of vector gsm beams , including the propagation - induced polarization changes , effect of the spectrum bandwidth and irradiance distributions in a unique way . there are some applications of the theoretical results 基于空間一頻率域中交叉譜密度函數(shù)的傳輸理論,研究了多色矢量gsm光束通過abcd光學(xué)系統(tǒng)傳輸時(shí)偏振特性的變化規(guī)律,首次推出了矢量高斯一謝爾模刑fgsm )光束通過近軸abcd光學(xué)系統(tǒng)交叉譜密度矩陣的傳輸公式,并對(duì)矢量gsm光束傳輸中偏振的變化、譜寬的影響和強(qiáng)度的分布等進(jìn)行了統(tǒng)一研究。
Chapter 4 : the paraxial propagation of partially coherent beams with the hermite - gaussian mode is investigated . the more generalized and simple expressions of the mean squared width and the beam quality factor of the beam with different mode order are obtained in terms of the cross - spectral density . our re - sults show that the higher order strengthens the variations of the mean beam width and the beam quality factor for partially coherent beams , and the relation between the two parameters of partially coherent beams is independent of the coherence length 第四章:初步探索了部分相干厄米高斯光的傍軸傳輸,根據(jù)交叉光譜密度得到了其不同模階數(shù)的平均光束束寬和光束質(zhì)量因子更一般的解析表達(dá)式,較高的模階數(shù)使得光束展寬得越快,光束質(zhì)量變差,且這兩個(gè)光束參量的關(guān)系與部分相干厄米高斯光的相干長度無關(guān)。