Correlation Spectroscopy with Noise Light Excitation

研究了噪声光激发下的高分辨率光谱。该光谱学基于噪声光的宽带激发、波形相关和傅立叶分析。研究了Rb原子的噪声激发谱，阐明了两种相关得到的傅立叶谱上信号产生的机理。在发射和发射波形的傅里叶光谱上观测了D_1跃迁的基态和激发态的塞曼信号，比较了自相关和互相关得到的信号，并利用线性响应理论分析了观测信号的线形。噪声激发光谱的原理是由线性系统理论推导出来的；线性时无关系统的特征是对具有频率无关功率谱的随机扰动的响应，通常称为白随机噪声。噪声激发光谱的特性如下。高分辨率；频率分辨率由测量时间的倒数决定，与光源的光谱宽度无关。灵敏度高；与传统的扫频方法相比，锐利线的信噪比大。吸收型和色散型光谱可以同时得到。不均匀展宽的影响可以消除。

A high-resolution spectroscopy with noise light excitation is studied. This spectroscopy is based on broad-band excitation with noise light, wave-form correlation, and Fourier analysis.A noise-excitation spectroscopy in Rb atoms was examined to clarify the mechanism of the signal generation on the Fourier spectra obtained from the two types of correlation. The Zeeman signals of the ground and the excited states of the D_1 transition were observed on the Fourier spectra of the transmission and the emission wave forms, the signals obtained from auto-and cross-correlations were compared, and the line shapes of the observed signals were analyzed by using a linear response theory.The principle of the noise-excitation spectroscopy is derived from the theory of linear systems ; linear time-independent systems can be characterized by the response to a stochastic perturbation with a frequency-independent power spectrum, usually called white random noise. The characteristic of the noise-excitation spectroscopy is as follows. High resolution ; the frequency resolution is determined by the inverse of the measuring time and independent of the spectral width of the light source. High sensitivity ; the signal-to-noise ratio for sharp lines is large as compared with conventional frequency-sweep method. Spectra of absorption and dispersion types can be obtained at the same time. The effect of inhomogeneous broadening can be removed.