The Simulation Study On The Double Varied Line Spacing Gratings Syatem

Bi-grating system composed of two periodic gratings with dispersion-combination of spectral imaging effect,can make multiple wavelength light beam through the first grating which form the dispersion spectrumd and the second grating which converge spectrum,and form de-dispersion virtual image,the effect has good application prospect.Varied line space plane grating can form virtual image and real image,the double varied line spacing gratings system is of its own characteristic,compared with bi-grating system composed of two periodic gratings,therefore,it is of value theoretically.In the thesis,the imaging characteristics of varied line space plane grating is studied with computer simulation.the laws between astigmatism,dispersion,magnification and object distance,grating parameters are discussed in the paper respectively.Research is mainly focused on the condition that multiple wavelength beam join to form a beam by two different types of double varied line spacing grating system and the imaging law of bi-grating system is studied.First of all,appling spatial ray tracing method of geometrical optics,anumerical approach is presented for calculated the location of the image point and the simulation calculation method of astigmatism is given.Secondly computer simulation was used to study the imaging characteristics of varied line space plane grating,the laws between astigmatism and the incident angle,the object distance,the grating parameters are analyzed.In the condition that astigmatism is very small,the laws between chromatic aberration and the object distance,grating parameters are analyzed,as well as the relationship between magnification and object distance,the grating parameters.Finally,the condition that multiple wavelength beam join to form a beam by two different types of double varied line spacing grating system are studied,as well as the imaging law of bi-grating system.