Powerful module for gas analysis, based
on our robust and approved "Rocket" FTIR with 4 wave-numbers resolution,
and an ultra-compact 5 meters optical path, low volume ( 0.2 Liter)
multi-pass heated cell. GASEX is, to our knowledge, the most compact gas
analyzer module on the market, optimized for your applications.
Optical design of the system
Interferometer coupled to a white cell
The Gasex system consist of an interferometer module
including also the MCT detector and an IR light source and a
Multi-reflection gas cell. The light is produced by a black body
radiation module and modulated by a dual corner cube interferometer.The
light is then coupled into the Gas cell (where the gas to be analysed is
injected) where it is relfected back and forth 32 times. Finally the
light focused on the MCT detector.
How does the interferometer work?
Permanentely aligned interferometer
The heart of the FT-Rocket is dual corner-cube
(retro-reflector) interferometer. The two corner-cubes are solidary to
a common swinging arm, which rotates to create an optical path
difference in the two arms of the interferometer.
This type of design is called a permanently aligned
interferometer, as the alignment of the system is known to be the most
robust against vibrations and temperature drifts. It never has to be
realigned.
The swinging arm of the interferometer rotates on wear-free flexure system, making this mechanical system extremely robust and durable.
Solid-state reference laser
For measuring the movement of the mirrors, a
solid-state reference laser is coupled into the interferometer. Compared
to classic HeNe lasers, the solid-state lasers that we use are more
compact and have a much longer life-time. They have a very low
temperature-induced wavelegnth drift and, when kept at constant
temperature with a Peltier element, their wavelength can be stabilized
to a few PPM, thus providing a very accurate and reproducible wavelength
scale. This is crucial for ensuring a day-to-day and unit-to-unit
consistency..