High-speed broadband FTIR system using MEMS.
Current Fourier transform infrared spectroscopy (FTIR) systems have very good spectral resolution, but are bulky, sensitive to vibrations, and slow. We developed a new FTIR system using a microelectromechanical system (MEMS)-based lamellar grating interferometer that is fast, compact, and achromatic (i.e., does not require a beam splitter). The MEMS device has >10  mm2active surface area, up to ±325  μm mechanical displacement, and a 343 Hz resonant operation frequency. The system uses a 5 MHz bandwidth custom infrared (IR) detector and a small emission area custom blackbody source to achieve fast interferogram acquisition and compact form factor. Effects of lamellar grating period, detector size, laser reference, apodization, and averaging of data on the spectral resolution are discussed. The measurement time ranges from 1.5 to 100 ms depending on the averaging time. In the target range of 2.5-16 μm (625-4000  cm-1) a spectral resolution of 15-20  cm-1is demonstrated. The measurements are shown to be stable over a long time.
N
N
Pelin Ayerden
Ugur
U
Aygun
Sven T S
ST
Holmstrom
Selim
S
Olcer
Basarbatu
B
Can
Jean-Louis
JL
Stehle
Hakan
H
Urey