Research On The Performance Of Multiple Vector Polarization Grating Arrays

Polarization detection technology as a new research method,has got attention of researchers around the world.It makes use of the polarization characteristics of objects to detect objects.Compared with traditional optical detection technology,polarization detection technology is able to effectively improve the recognition rate of the target.The detection process is mainly through the polarization characteristics of light to increase the information object dimensions,such as polarization degree,polarization angle and polarization ellipticity,radiation rate parameter information.It can achieve accurately target identification and ground discrimination.With the development of polarization detection technology,now it has been widely used in medical,military,civil and other fields.Two kinds of grating polarization array structure were designed based on stokes vector.One is four-direction(0°,45°,90°,45°)rectangular grating array,another is all polarization stokes vector grating array which is consisted of rectangular grid and Archimedes spiral.The grating structures were simulated based on the finite difference time domain method of FDTD.The grating array structures with aluminum film as base were fabricated using electron beam lithography(EBL)and inductively coupled plasma etching(ICP),tested by self-assembly optical measurement system.From the gray scale patterns of the grating array,extinction ratio and transmittance were calculated.And the influence on the grating performance by the indexes of the polarization array such as cycle,duty cycle,line width and groove depth was analyzed.Because of the proximity effect of adjacent gratings,crosstalk noise of fabricated grating polarization detector was analyzed.Kinds of noise source and characteristics of the system were discussed,the signal-to-noise ratio of the two different grating array structure was calculated.It is concluded that the signal-to-noise ratio of grating array structure can be influenced by the angle of incident light.