Translator Disclaimer
22 August 2000 Low-cost microspectrometer
Author Affiliations +
Proceedings Volume 4178, MOEMS and Miniaturized Systems; (2000)
Event: Micromachining and Microfabrication, 2000, Santa Clara, CA, United States
We present a tunable interference filter for IR and visible light that scans the desired part of the optical spectrum within milliseconds. A single pixel detector measures serially the intensity at selected wavelengths. This concept avoids expensive linear detectors as used for grating spectrometers. The tunable optical interference filter is fabricated by a new porous silicon batch technology using only tow photolithography steps. The refractive index of this filter microplate is gradually modulated in depth to create a Bragg mirror or a Fabry-Perot bandpass filter for a transmission wavelength between 400 nm and 6 micrometers . Two thermal bimorph micro-actuators tilt the plate by up to 90 degrees, changing the incidence angle of the beam to be analyzed. This tunes the wavelength transmitted to be detected by a factor of 1.5, e.g. form 4 micrometers to 6 micrometers . The filter area can be chosen between 0.27 mm by 0.70 mm and 2.50 mm by 3.00 mm, its thickness is typically 30 micrometers . The spectral finesse of 25 is sufficient for most diagnosis applications, e.g. detection of CO2 and CO in combustion processes by their IR absorption bands. Online colorimetery and color correction of desktop printers can be envisaged.
© (2000) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Gerhard Lammel, Sandra Schweizer, and Philippe Renaud "Low-cost microspectrometer", Proc. SPIE 4178, MOEMS and Miniaturized Systems, (22 August 2000);

Back to Top