InfraTec’s microspectrometer detector with ASIC-control

Detectors with a tunable Fabry-Pérot filter (FPI), which have an integrated closed loop control, rank among the latest as well as technically most sophisticated developments in the field of infrared sensors. InfraTec is one of the pioneers of this technology and offers four types with different spectral tuning ranges from 3 to 10 µm in a TO8 housing.

Common for all of these is its increased resistance to external and internal interference effects, which ensures exact, long-term and repeatedly accurate measurement stability. The closed loop control by means of an ASIC circuit is responsible for this. This allows the position of the moving reflector plates of the tunable Fabry-Pérot filter integrated in the detector to be permanently measured and undesirable influences, such as the force of gravity or thermal changes, to be compensated for within the shortest possible time.

For regardless of the application, detectors are often subjected to dynamic or static accelerations. It is sufficient to turn a portable measurement device in your hand. Even the inline measurement in industrial environments is frequently associated with disturbing vibrations. In addition to the ASIC, the housing of the detector also includes an EEPROM, which has data ready for the temperature calibration of each specific detector. A supplied detector circuit board can be easily integrated into the system environment of the user. The interaction between ASIC, EEPROM and detector circuit board supports the reliable operation of the FPI detectors.

Operation in closed loop control, increased resilience to acceleration forces as well as compensation of the temperature drift leads to an extremely stable central wavelength. Compared to controlled detectors, the deviation of up to ± 40 nm drops to just ± 2 nm. Consequently, users benefit from constantly high measurement quality.

Since FPI detectors from InfraTec are manufactured by bulk micromachining, they do not only due to this high degree of precision, but due to a very wide tuning range as well. This tuning range is considerably wider than with solutions whose design is based on surface-micro-mechanics, since the optical system inside the detector is decoupled from the control system. Consequently, a vast range of potential applications are opened up.

Furthermore, FPI detectors are characterised by powerful signal generation. The main reason for this is the large aperture of up to 2mm in diameter. The reflectors attached to sturdy supports remain stable even under changing thermal conditions. This means that any undesirable change in the tuning range is effectively prevented. Thanks to the large reflectors, the detectors gain a high degree of visual performance, which reaches a moderate spectral resolution of a few ten nanometres. This sensitive tuning proves ideal for numerous applications ranging from environmental, climatic, building and safety technology, process measurement technology, liquid analysis to medical technology and respiratory gas analysis.

Please click here for further information.