Study On Fabrication Of Convex Grating By Native Substrate Grating Mask

Hyperspectral imaging spectrometer is an important measurement and analysis instrument,which has many advantages such as high resolution,timeliness and wide measurement range.It has been widely used in many fields such as resource exploration,agricultural production,medical and health,scientific research and military detection.Convex blazed grating is one of the key elements in imaging spectrometer.Generally,the effective wavelength coverage of blazed grating is not broad enough to meet the need of imaging spectrometer for grating? s diffraction efficiency.To extend the observation band of imaging spectrometer,convex double blazed grating is an effective medium.The fabrication of convex dual-blaze grating by holographic ion beam etching is investigated theoretically and experimentally in this paper.The main consists are as follows:First,the fabrication methods of convex blazed grating and the research status at home and abroad are introduced.The ion beam etching and Kaufman ion source system are reviewed.The relationship of the ion beam incidence angle and the etching rate of the material(quartz and photoresist)is received in pure Ar and CHF3 by summing up previous experiment data.It offers theoretical basis and experimental guidance for the fabrication of native substrate grating mask and the formation of blaze angle.Then,some diffraction efficiency theories of grating are introduced,the relationship between the blaze angle and the diffraction efficiency is emphatically analyzed.And determine the blaze angles of the convex dual-blaze grating.For the photoresist mask is difficult to meet the requirement for the fabrication of convex dual-blaze grating in the traditional holographic ion beam etching technology.The relationship between the blaze angle and the incidence angle of the ion beam is analyzed,providing theoretical guidance for the fabrication of the blazed grating.Finally,in experiment,native substrate masks and convex blazed gratings with the blaze angles of 6.5°,7°,11.3°and 14.1° are obtained that validates the etching model.Then a convex Dual-Blaze grating whose blaze angels are 6.3° and 17.3°,anti-blaze angles are 66° and 56° are obtained.For experimental measurement,the first order diffraction efficiency of the proposed grating which coated a level aluminum is measured,and compared with the theoretical values.