Investigation Of Color Filtering Device Based On Sub-wavelength Compound Grating

Nanostructured polarization and filter devices based on sub-wavelength gratings have obvious characteristics,such as high utilization of light energy,adjustable bandwidth and large angular non-sensitivities.Such structures can be fabricated by micro-nano manufacturing technology and be applied in many fields,such as new low-energy flat panel display,ink-free nano-printing and security anti-counterfeiting et al.One kind of color filtering device based on sub-wavelength dielectric-metal compound grating is designed and discussed in visible wavelength:Red,Green and Blue filtering coloration.The main objective of this study is to design a color filtering device with large receiving angle,high TM transmission efficiency and wide bandwidth.The main research work of this paper is summarized as follows:(1)The main theoretical research methods of grating are introduced:Effective-medium Theory(EMT)and Rigorous Coupled-wave Analysis(RCWA).In this thesis,RCWA method is used to design and analyze the sub-wavelength grating.(2)One kind of sub-wavelength dielectric-metal compound grating is designed and discussed by RCWA and Matlab computation.The characterization of TM polarized transmission is studied under changing different parameters of the grating structure,such as grating period,grating duty cycle,layer thickness and incident angle.Red,Green and Blue based band filtering transmission are achieved and calculated.The peak wavelength,Full Wavelength Half Maximum(FWHM),diffraction efficient and coloration are simulated and analyzed under different Parameters design.(3)3-Channel color filtering device is designed and the grating structure parameters are further optimized.The central wavelength of the color filter is separately at 660nm,510nm and 435nn.The peak efficiency is more than 82.6%,the FWHM is 165nm?130nm and 105nm respectively,and the insensitive incident angle is more than 45 degrees.The designed structure is suitable for the filter of transmission display and has potential application value in related fields.