Abstract: Infrared detectors using electric property of sensitive material, convert temperature change into electrical signal, which can be tested by the readout circuit.And the absorption rate is low.By using bottom grating structure of high reflectance, the transmission light can be absorbed twice and absorption of infrared detectors can be improved.The effect of the structural parameters on the absorption characteristics was analyzed based on the electromagnetic field theory.Numerical simulation results show that the average absorption efficiency of a detector can be doubled by optimizing the structure parameters in whole wavelength range.

Key words: Infrared detectors using electric property of sensitive material, convert temperature change into electrical signal, which can be tested by the readout circuit.And the absorption rate is low.By using bottom grating structure of high reflectance, the transmission light can be absorbed twice and absorption of infrared detectors can be improved.The effect of the structural parameters on the absorption characteristics was analyzed based on the electromagnetic field theory.Numerical simulation results show that the average absorption efficiency of a detector can be doubled by optimizing the structure parameters in whole wavelength range.