Theoretical Study Of Terahertz Radiation Intensity And Conversion Efficiency Via Optical Rectification

With the application of terahertz increasingly widespread, terahertz generationhas become a hot topic in recent years. Since the optical rectification method ofgenerating the terahertz wave has a relatively high resolution, the wider spectrum ofthe terahertz wave, and test is relatively simple adjustment, currently opticalrectification method widely studied. This topics through general nonlinear mediumand chiral media，generating a terahertz wave with optical rectification method,method to generate a terahertz wave with optic rectification light intensity ofradiation and the conversion efficiency were analyzed. And comparative analysis ofchiral medium optical rectification method to generate terahertz is superior to thegeneral nonlinear medium.Firstly, general nonlinear medium for optical rectification method of generatingterahertz radiation intensity was calculated and analyzed. Wave equation by theincident laser irradiation on the general nonlinear media to start calculatinggenerated terahertz radiation intensity, since the calculation of the approximate,medium length can be divided into large (millimeter) and small (micrometers)thickness. If we consider the circumstances under absorption, because of therelationship of the absorption coefficient, this article is only made part of thecalculation. Then, on the basis of the calculated THz radiation intensity of thegeneral nonlinear medium, the conversion efficiency were calculated and analyed.We obtained optical rectification generating terahertz conversion efficiencyexpressions and curves in general nonlinear media under small and large thickness.Sencondly, studied the terahertz radition conversion efficiency by opticalrectification method in chiral medium. Wave equation by the incident laserirradiation on the chiral media to start calculating generated terahertz radiationintensity, and simulated the intensity change with the chiral medium length andfrequency curve. Based on this calculation, we can derive out the express ofterahertz radiation conversion efficiency generating by optical rectification in chiralmedia, and numerical simulation the curve of conversion efficiency change withchiral media length and width.Finally, comparative anlysis of chiral media and general nonlinear mediumperfornance of teraherz radition intensity and the conversion efficiency generated byoptical rectification method. For a more objective description that the performanceof chiral medium optical rectification method generates terahertz radiationconversion efficiency better than general nonlinear, after improvement general nonlinear that is periodically poled nonlinear generates terahertz radiationconversion efficiency by optical rectification method were studied. Eventually thesethree medium optical rectification method generates terahertz radiation conversionefficiency’s performance were comparative analyzed.This topic have some value of the producing terahertz，for chiral mediumhaving a better nonlinear effect, is a relatively good medium for generating terahertzwave. This topic also promote the application of terahertz waves have somesignificance.