Mems Programmable Grating And Its Applied Research, Gas Monitoring

A diffractive MEMS element is an optical component with adjustable diffraction efficiency. It can provide significant advantages in optical applications and is production proven in markets such as displays and commercial printing. Micro programmable grating is a typical diffractive MEMS device. The device typically consists of parallel rows of reflective ribbons that are separated from a silicon wafer by a thin air gap. Each of these ribbons can be individually positioned vertically in an analog fashion using electrostatic actuation. Besides spectral analysis, Micro programmable grating will be very important in optical telecommunication.In the thesis, the optical model of Micro programmable grating is constructed, analyzed theoretically and simulated by mathematical methods. The principle of synthesizing a spectrum by the programmable grating is analyzed and testified by the simulation. The application of the micro programmable grating in correlation spectroscopy for remote monitoring of gas is introduced. The main contents of this thesis are as following:Firstly, based on the wave optics and the geometrical optics, the optical model of Micro programmable grating is constructed and analyzed theoretically. Diffractive light intensity distribution formulae of Micro programmable grating are developed. Then, simulation is implemented by mathematical methods to analyze the effect of the parameters of the optic incident and grating structure on diffractive light intensity. The simulation results show that compared with common gratings, Micro programmable grating has unique capacity of energy redistribution, which is quite advantageous to spectral analysis.Secondly, the diffractive field of programmable grating is analyzed when an incident light is collimated from vertical direction. It is showed that the state of the micro programmable grating can be prescribed and the diffractive emergent light will correspond to spectra of target substance, i.e. synthetic spectra. Meanwhile, a method of synthesizing a spectrum by the programmable grating is proposed. A novel gradient-based optimization algorithm is presented for the synthesis of spectra at a...