<title>The Saw Tooth Groove Profile Controlling Method Of The Blaze Holographic Grating</title>

Abstract

The Saw Tooth Groove Profile Controlling Method of the Blaze Holographic GratingZhu Shao-JiShanghai Optical Instrument Research Institute, China AbstractA new technique concerning the production of blaze holographic gratings by using Fourier synthetic method is proposed. The description of the holo-grating ( 1200 G/inm, blaze angle 8 38', blaze wavelength 2500 A ) with synthetic groove profile is given and the comparison with the theoretical result is conducted. The calculation of the phase-shift of reflection light wave is also given. An experimental setup which is simple in construction, convenient in adjustment and high precision in control is put forward.IntroductionComparing with the ruled grating, the holo-grating possesses several advantages for obtaining high signal to noise ratio, elimimating ghost and stigmatism. And what is more, grating with larger ruled area and higher groove density can also be made by using photographic method. In the past years with the steadily impro­ vement of the spectral properties of the holo-grating, it has already found its wide applications.Unfortunately, the holographic grating also has some disadvantages, mainly, its diffraction efficiency is low. In order to obtain high diffraction efficiency, we have to control the groove profiles, that is, to generate the saw- tooth shape holo-grating with blaze property.Recently,several authors have proposed different kind of methods for .controlling the groove ^profile of holo-grating, there are Fourier synthetic method ' , standing wave method as well as ion-etching method . A new proposed technique concerned with the production of the holographic blaze grating with high performance by means of Fourier synthetic method is put forward in this paper.PrincipleThe groove profile of the plane diffraction grating with characteristics of bla­ ze is shown in Fig. 1 , which can be described by the period d:y = f (x) = tg£- x ( - j < x < | ) . (1 )function f(x) is odd function, which can be expanded in terms of Fourier sine series, i.e.