Performance and applications of a spectrometer with micromachined scanning grating
Micro Optical Electro Mechanical Systems (MOEMS) gain more and more importance in technical applications. The combination of optical actuators and micromachined silicon technology arise possibilities to realize equipment in high volumes for reasonable prices, that have formerly been expensive laboratory equipment. This paper reports on the performance and applications of a spectrometer in MOEMS technology. It is based on a scanning mirror chip with a grating structure on top. Thus a spectrometer with selectable wavelength range was realized. The resolution is not limited by line width of a multisensor detector, as it is the case for state of the art low cost spectrometers. A single detector is used, cheaper than arrays and available for all wavelength ranges. The setup can be small and light, the grating withstands shocks and vibration much better than a classical spectrometer. The grating moves with a frequency of 500 Hz respectively 1000 Hz, a whole spectrum is acquired within milliseconds. The resolution is given by the grating line density and the spectrometer dimensions, as it is valid for every single detector spectrometer. Depending on the number of systems built, a price of the system can be expected significantly below those of low cost systems with fixed grating. Many possibilities arise in every application where light is analyzed spectroscopically.