Broadband Transmission Properties of cBN-Si Interfaces

We analyze the real and imaginary parts of cBN in a broad wavelength range both 0.5-1.0 μm and 1.36-10 μm respectively, and use both Fresnel theory and Meep software package to calculate the transmittance and reflectance. The theoretical and numerical results show that the transmision and reflection on the interfaces mentioned above have an abnormal phenomenon, and the physical mechanism is analyzed. Between 0.5 μm and 1 μm, the cBN film is transparent with the transmissivity equal to the order of 1.0. When the light wavelength is in the range of 4-9 μm, the structures made of cBN and Si, such as cBN film, cBN-Si double layer film and multiple layer film, have the same optical characteristic with the highest reflectivity and lower absorptivity and zero transmissivity. These findings can be used in the structure design of the optoelectronic devices, such as the optical bandpass filter, the optical bandstop filter, the optical attenuator, the photodetector, and the solar cell.