Study on Nearly Perfect Absorber Based on Periodic Nano-structure
Author:Luo Ming Hui
Supervisor:chen lin sen zhou yun
Periodic nano-structure can manipulate and tailor spectrum purposefully and selectively,which has an extensive application prospect in photovoltaic,opteelectronics,sensing,detection,inkless printing,photothermal converter,et al.This thesis deals with visible spectrum tailor and manipulation based on periodic nano-structure.To satisfy the requirements of structural color anti-fake,inkless printing,et al,three kinds of single-wavelength nerarly perfect absorbers and four kinds of broadband wide-angle absorbers are proposed.Ulteriorly,two kinds of broadband wide-angle absorbers have been prepared and verified.The main contents and innovations of this thesis are listed as following:(1)The single-wavelength absorbers previously reported,which usually employ precious metal materials,are bad for manufacture.We design three kinds of single-wavelength absorbers by employing non-noble materials.The first consists of dielectric grating coverd with aluminum.The nearly perfect absorption can be achieved due to the excitation of cavity mode under the TM polarization.The second is stacked grating over metal base.The stacked grating consists of high refractive index dielectric and aluminum.The polarization-independence absorption can be achieved by trapping electromagnetic energy in dielectric grating.The last is metal grating filled with delectric material.The electromagnetic energy excited by differently polarized lights is trapped in dielectric cavity,so that the polarization-independence can be obtained.The complexity of the absorbers is amazingly reduced from two dimensions to one dimension.(2)The broadband absorbers previously reported,which usually employ complex structure and tedious craft,are difficult to be fabricated.This thesis proposed four kinds of broadband wide-angle absorbers.The first is composed of metal-dielectric-metal grating.The broadband absorption can be maintained over a wide range of incident angle up to 45° under the TM polarization.The second is metal grating filled with dielectric material.The highly broadband absorption can be obtained for TM and TE polarization.The third is metal-delectric-metal arrays.The polarization-independence absorption can be maintained over a wide range of incident angle up to 60°.The last consists of nickel arrays.The average absorption is over 90% in the visible regime.(3)Two kinds of broadband absorbers have been fabricated.The absorber consists of metal-dielectric-metal arrays have been fabricated by the continuously variable spatial frequency photolithography and nanoimprint lithography.The absorber consists of nickel arrays have been fabricated by the double-beam holographic lithography and electroforming technology.To verify the correctness of theoretical calculation,the performances of two kinds of absorbers have been measured.