Infrared Absorber Based On InP,InAs And InSb Materials

Surface plasmons are waves that occur under the interaction between the free electron in the surface of metal and the incident wave.In recent years,the absorbers based on surface plasmons excitation have gradually become a research hotspot of scientists,especially for the absorption performance of electromagnetic waves in infrared band.In this paper,firstly,some related concepts and excitation characteristics of surface plasmons are introduced,and the development and applications of absorber as well,especially infrared absorbers in recent years.On this basis,two infrared absorber combing In P,In As and In Sb have been designed and the electromagnetic wave absorption properties of specific infrared bands are studied by Finite Difference Method in Frequency Domain(FDFD).The main studys are as follows:(1)A grating absorber structure with depth linear gradient groove is proposed.In In Sb with silver base at the bottom,grooves are excavated at same distance,and In As and In P materials are coated on the inner wall of the groove in turn.FDFD method is used to optimize the absorption effect continuously,and the perfect absorption of incident infrared electromagnetic wave between 28-75?m band is achieved at last.Moreover,the independent absorptivity is also realized between 0-80 o incident angle.Finally,the influence of structural parameters on absorption effect is also studied: the absorptivity is closely correlated with the number of the grooves,while barely associated with the depth of the grooves,the width of the grooves,the thickness of the coating as well as the period of the grating.(2)A tapered plasmonic ultra-broadband infrared absorber stacking by indium phosphide(In P)?indium arsenide(In As)?indium antimonide(In Sb)is presented.For this absorber,the width of the composite layer increases gradually from the top to the bottom,which is on the silver substrate,and each composite layer is in turn In P,In As,In Sb and dielectric materials fromtop to bottom.The distribution of magnetic field at different incident wavelengths is studied as well as the local electric field distribution at corresponding wavelengths,so that the absorption mechanism of the absorber can be explained more intuitively and clearly.In addition,the influence of absorptivity on the structure parameters is also researched.Found that the number of the composite layer and the thickness of the three semiconductor materials have a relatively great influence on the absorption,however the width of the composite layer and the thickness of the dielectric material has less influence on the absorptivity.Finally,the influence of absorptivity on the thickness of the silver layer is discussed.It is found that the absorptivity will be very low without the silver base layer,however,it is enough to resist the transmission of electromagnetic wave when the thickness of the silver layer is above 0.15?m.The absorbers designed in this paper are expected to advise the manufacture and application of infrared absorbers in the future.