Hyperfine Spectroscopy Detection Theory Based On Degenerate Four-wave Mixing

In modern material of measuring technology, microscopic characteristics of material structure are revealed by fine spectra and hyperfine spectrum. Laser spectroscopy is the best measurement for fine spectrum and hyperfine spectra. Currently, there are lots of laser analyzing methods,which however, all have the disadvantages such as low resolution, high detecting limit, large sample consuming amount, high price and so on. To deal with these problems, a new method for isotope analyzing based on degenerate four wave mixing (DFWM) is proposed. Using the third-order nonlinear effect, selecting the appropriate parameters of third order nonlinear approximate, establish the equivalent grating double-beam interference model, thus paper work includes the following aspects:(1) Summarized and reviewed hyperfine spectral detection theory research and development situation of various methods, characteristics and range.(2) selected detection model using detection means for laser third-order nonlinearity effect of degenerate four-wave mixing, through the solution in establishing a third-order nonlinearity equivalent grating double-beam interference model in the process of grating measuring model, preferences and approximate problem, establish third-order nonlinearity equivalent grating double-beam interference model.(3) By the study of medium can be measured with the incident light intensity, the temperature distribution is deduced, and the refractive index variation caused by temperature get, therefore, contains sample information of beam amplitude can be solved through diffraction Bessel function,then, get third-order nonlinearity equivalent grating double-beam interference model combining mould.:degenerate four-wave mixing frequency spectrum technology needs of the most important properties. Finally, discussed based on degenerate four-wave mixing of hyperfine spectra of the theory.Third-order nonlinear equivalent grating double-beam interference model test samples can be directly obtained without the micro information, its measurement spectra, has the detuning of ultra-fine spectral resolution capability, Measuring high efficiency, testing samples can be covers solid, liquid, gas, and the three required amount is small, for all kinds of measurement model is a new kind of fixed and supplement.