Research On Three Bodies Near-field Radiation Property With Silver Grating Structure

Due to the development of Micro-Electro-Mechanical System,the systems that we research have reached to micrometer and nanometer scale.Because of the size effect,the evanescent electromagnetic waves,existing at the very surface of solid structure,can strongly engage in the radiation heat transfer,so called as near field radiation transfer.In recent years,the need for novel near field microscopy and control of photons in microscale,has pushed the near field radiation theory to develop from two bodies system into three bodies system.However,since the complexity of equations to calculate the radiation in three bodies system,the current description of evanescent photon's radiation transfer stagnates in the slab-film layered system,and a subwavelength calculation is needed.Focusing on the three bodies system with mutual independent temperatures,the equations for slab-film structure have been extrapolated into the subwavelength case.The Rigorous Coupled Wave Analysis is used to calculate the scattering factor of specific order of scattering evanescent waves to assembly the scattering matrix,and then the radiation transfer in three bodies system is computed.Using the equations for evanescent wave radiation transfer in three bodies subwavelength structures,the heat exchange in Ag substrate-Ag/Si O2 grating-Ag substrate system is analyzed.It's found that by tuning the filling ratio in the Ag/Si O2 grating,the single or double intensive tunneling can be achieved.By studying the transmission contours in Ag substrate-Ag/Si O2 grating-Ag substrate three bodies system and those related,the reason for intensive tunneling is explained as the coupling between spoof surface mode and cavity mode.The spoof surface mode originates from the surface phonon polariton of Si O2,which is mediated by the subwavelength structure.The cavity mode originates from the multi-reflection between surfaces.By utilizing the effective medium theory,the relation between filling ratio of grating and scattering of spoof surface mode is built,and it is employed to predict the resonant frequencies of tunneling modes.Finally,the temperature differences and the geometric effects on resonant frequencies,bandwidth and flux intensity are discussed.