SILICON MICROMACHINED INFRARED-SENSOR WITH TUNABLE WAVELENGTH SELECTIVITY FOR APPLICATION IN INFRARED-SPECTROSCOPY

The techniques of silicon micromaching have been used to develop a min iature infrared sensor with tunable wavelength selectivity for applica tion in infrared spectroscopy. The infrared sensor consists of a tunab le interference filter in front of a wide-band detector. The applicabl e spectral bandwidth ranges from 1.5 to 7.5 mu m. The resolution is be tter than 25 nm over the whole range. The wavelength tuning and parall elism control of the mirrors is carried out by electrostatic forces, v arying the voltage at the integrated disk capacitors. The transmitted infrared radiation is absorbed in a black gold layer, the rising tempe rature being measured by a thermopile consisting of 80 Si-Ni thermocou ples. This device is expected to find application as an emission monit or for liquids and gases.