Proceedings Article | 8 September 2011
KEYWORDS: Mirrors, Spectroscopy, Diffraction gratings, Microelectromechanical systems, Infrared spectroscopy, Sensors, Diffraction, Spectral resolution, Optical design, Collimation
Infrared (IR) spectrometers are very important optical equipments that can be used in industry, science, medicine,
agriculture, biology and food safety etc., and the market is growing. However, most traditional IR spectrometers, such as
Fourier transform spectrometer (FTS) that based on Michelson interferometer principle and scanning monochromator
that based on grating scanning, are expensive, relative large volume, and stationary, which can't meet the requirements of
specific application such as rapidity, special environment and some special samples. To overcome these drawbacks,
innovatory technology-micro electro mechanical systems (MEMS) technology was used in micro IR spectrometers in the
past few years. And several prototypes and products that based on several operational principles have been emerged. In
this paper, a novel IR micro spectrometer which based on MEMS technology and used single element detector was
presented over a wide spectral range (from 2500nm to 5000nm) in the mid infrared (MIR) wavelength regime, and the
optical system of it was designed on the basis of traditional scanning monochromator principle. In the optical system,
there is a highlighted characteristic that dual spherical focus mirror was used to focus the diffraction light of the
diffraction grating, which improved the spectral resolution of the optical system. Finally, using Zemax optical software,
three torsion angle locations were selected to simulate the optical system of the spectrometer with the slit's size
0.1mm×1mm. The simulation result indicated that in the whole wavelength range the spectral resolution of the optical
system was less than 30nm, and a high accuracy MIR spectrometer with compact volume will be realized in future
hopefully.
