Fundamental performances of a micro stationary Fourier transform spectrometer

Abstract : A new configuration of micro-spectrometer based on an infrared stationary Fourier transform (FTIR) interferometer has been developed at ONERA. Our device is based on a classic infrared focal plane array (FPA) of HgCdTe technology with a built-in two-wave wedge-like interferometer. This new architecture generates research works in several domains. Technological researches are conducted in collaboration with the CEA to optimize the manufacturing process and reduce the technological defects. In parallel, researches in optical design are conducted to implement the FTIR-FPA in a complete system. For this, theoretical work is needed to understand and describe the fringes formation inside the detection structure when illuminated by a wave which is not ideal, i.e. emitted by an extended source positioned at a finite distance from the detection plane. The results of this theoretical study are presented. These results are exploited to design a compact spectrometer with a very simple optical architecture. First experimental data are presented and discussed.