A Fabry-Perot interferometer-based long-wavelength infrared spectrometer utilizing a novel PDMS patterning technique

We report a Fabry-Perot interferometer (FPI)-based infrared (IR) spectrometer designed for long-wavelength infrared (LWIR) region. To fabricate the proposed FPI-based LWIR spectrometer, we developed a novel poly(dimethylsiloxane) (PDMS) patterning technique by combining photolithography and dry etching. The proposed PDMS patterning technique has advantages such as clear shape of PDMS pattern and no damage to the silicon (Si) substrate. Especially, the final height of PDMS pattern is easily adjusted by controlling the thickness of spin-coated photoresist. The proposed FPI-based IR spectrometer, which is composed of upper and lower substrate were fabricated separately utilizing newly proposed PDMS patterning technique. Experimental results show that maximum transmittance of filtered wavelength component by the proposed FPI-based IR spectrometer lies at the wavelength of 16 μm. The proposed IR spectrometer can detect a specific wavelength at LWIR region by controlling the air etalon gap that is adjusted by utilizing the proposed PDMS patterning technique.