Progress of performance of MOEMS micro spectrometers through enhanced signal processing, detectors and system setup

Micro spectrometers have been realized by the use of MEMS based scanning grating chips several years ago. The main advantage is the requirement of a single detector instead of a detector array for micro spectrometers applying fixed gratings. Especially in the near infrared range beyond the detection limit of silicon detectors, this can help to reduce the system costs significantly. First measurements for test application have been performed successfully. Industrial applications require wide spectral range, high long term stability and sufficient computation power in the system itself to realize intelligent sensor heads for process monitoring and quality control. Through the recent time, many details have been improved. Extended InGaAs detectors have been used to extend the spectral range up to 2500nm. Improvements of the grating position readout improved the wavelength stability of the system even under tough operation conditions. The integration of faster digital signal processors opens the possibility to implement spectral evaluation algorithms into the system itself. Besides simple applications shown earlier like the selection of different kinds of plastic waste, now a more quantitative analysis can be achieved. For example the ethanol content of liquor samples has been measured and evaluated quantitatively.