Kırınım ızgaralı MEMS fourier dönüşümü spektrometre

Fourier Transform Infrared (FTIR) Spectroscopy is a widely used method for chemical and/or biological substance analysis and identification. FTIR uses a single photodetector instead of an array of detectors and offers several advantages over the other spectroscopy methods such as high signal to noise ratio, high throughput, compact form-factor, and low-cost. Currently the FTIR spectrometers are mostly bulky and sensitive instruments which can be used under laboratory conditions by trained persons. However, there is a great need for portable instruments in various industrial fields.In this thesis, a lamellar grating interferometer (LGI) device using Micro-Electro-Mechanical-Systems (MEMS) technology is developed as a part of an 7th framework project MEMFIS funded by EU, which aims at developing an ultra-small FTIR spectrometer system. The mechanical, optical, and electro-mechanical properties of the device are optimized and significantly improved compared to the state-of-the art in this area. Theoretical limits of the LGI are established using Fourier optics theory, and diffraction grating shape and period are optimized as part of the optical system design and optimization study. Numerical analyses are made to optimize optical efficiency of the device for the mid-wavelength infrared (2.5 ?m ? 16 ?m). To improve the mechanical design, pantograph-type spring suspensions are designed using ANSYS? finite element modeling tool to increase the translational amplitude of the device to ±500um and to improve shock and vibration survivability. Thus, the theoretical spectral resolution limit is enhanced to 10 cm-1, which should provide a 10-fold increase over the previous generation MEMS FTS system demonstrated at Koç University. Negative effects of the dynamic deformation of the grating reflectors on the spectral resolution are eliminated by limiting it to 300 nm by decoupling the mechanical springs from the diffraction gratings. Electro-mechanical properties of the nonlinear actuator are analyzed in detail and the expected full-performance should be achievable with <200V and without using a vacuum package.