The Design And Fabrication Of Convex Blazed Grating With Small Blaze Angle

The fabrication and characteristics of convex blazed grating with smallblaze angle are investigated theoretically and experimentally in this paper.The main contents are as follow:The significance of the research of the convex blazed grating and theprocess abroad and home of the research on convex grating are presented. Theion beam etching and Kaufman ion source system are reviewed. The etchingcharacteristic of photoresist, K9glass and quartz is studied, the etching rate ofmaterials is measured and analyzed as function of ion beam incident angle inpure Ar. It offers useful experimental gist and theoretical instruction for studyof divergence of the ion beam.Calculation of divergence of ion beam and its effect on blazed angleetched by ion beam are introduced in detail. The blazed angle etched by ionbeam cannot achieve below4°. We assumed that it’s because the effect ofdivergence of ion beam. We verify it through theoretical analysis andexperiment. We improved the collimation of ion source by adding baffle, andgain blazed angle of2.8°and3.4°on plain and convex substraterespectively.We reduced the blazed angle by spin(dip) coating with convex grating whose blazed angle is about4°. We verified the effects of different spin(dip)speed and concentration of photoresist on the final results. The reduction ofblazed angle is analyzed as function of coating thickness. We obtain convexblazed gratings with blazed angle1.85°、anti-blazed angle11.1°and blazedangle1.85°、anti-blazed angle12.7°by spin and dip coating respectively.