The heart of the FT-Rocket is dual corner-cube (retro-reflector) interferometer. The two corner-cubes are fixed to a common swinging arm, which rotates to create an optical path difference (with respect to the beam splitter) in the two arms of the interferometer.
This type of design is called a permanently aligned interferometer. This particular arrangement of the interfeormeter 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.

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..

Model	FTNIR-L1-025-2TE
Type of interferometer	Permanentely aligned, double retro-reflector design
Spectral range [cm-1]	4000 - 11000
Spectral range [nm]	900 - 2500
Spectral resolution in wavenumber:	2cm-1, 4cm-1, 8cm-1 (user selectable)
SNR (4cm-1 resolution, 1 minute scan time)	>100'000:1
Long term baseline intensity stability	< 2% (1100-2500nm) over 10 hours
Wave-number repetability	< 10ppm
Detector	Extended type InGaAs PIN photodiode, 2TE cooled
Scan frequency	>4 Hz @ 4cm-1
Optical fiber connector	SMA 905
Optical entrance	< 0.6mm (fiber core diameter) NA=0.25
Reference laser	Solid-state 795nm, temperature stabilized.
A/D converter	24 bit
Power requirements	10W (max) @12 VDC
Operating temperature	5°C-40°C
Communication interface	USB 2.0
Software interface	Windows 7, 10 & 11 API for controlling the instrument via our DLL
Dimensions	180mm x 160mm x 80mm
Weight	1700g

 

The resolution of Fourier-transform spectrometers is usually expressed in wave-numbers (ν), which are simply the inverse of wavelength (ν=1/λ). The conversion betwen wave-number resolution and wavelength resolution is Δλ = λ² · Δν. The the graph below shows this conversion for the situations where Δν = 2cm^-1, 4cm^-1 or 8cm^-1.

Yes. Although the ARCoptix FT-NIR is not a dispersive but a Fourier-transform spectrometer, accessories normally used with dispersive spectrometer are compatible. The spectrometer has a SMA-905 input fiber connector. One just has to take care that accessories are NIR compatible. For example, optical fibers must be rated "low-OH content" to avoid too high absorption in the NIR.

The precision of the wavelength scale in Fourier-transform spectrometers relies on its internal reference laser. In our compact FT spectrometers, the reference laser is a solid-state type whose central wavelength has a naturally low temperature-induced drift, ~70 ppm/ºC. In some applications, this is sufficient. But in other applications, a more reproducible wavelength scale must be achieved by the spectrometer. With the temperature-stabilization of the laser (via a thermoelectric element) a wavelength reproducibility < 10 ppm can be guaranteed all over the instrument operational temperature range (5-40 ºC). To give an example, at 1000nm wavelength, a shift of 10 ppm means 10E-6 * 1000nm = 0.01nm. This is especially important for applications such as laser characterization or chemometric analysis.

The AoDAQ is a multi-threading, cross-platform and versatile software that simultaneously takes care of:

• (1) Handling communication with the FT-IR via USB
• (2) Processing raw signals to deliver the spectrum
• (3) Running a TCP ethernet server

The AoDAQ can be installed on all sorts of computers, from desktop machines to embedded, low-power single board computers. Thanks to the hosting of a TCP server, the instrument data and parameters can be accessed locally and/or remotely. All communication with the instrument eventually reduces to a set of TCP/IP commands that allow to quickly acquire data, adjust parameters, monitor the instrument status etc. using the programming environment of your choice.

The FTIR Rocket is delivered with a free Windows 7 & Windows 10 compatible graphical user interface (GUI) program.

The free basic software package allows the user to:

• Configure hardware measurement parameters (amplifier gain, averaging, ...).
• Display real-time spectral measurement results.
• Set reference spectra (white, dark) and choose among raw spectra, transmission or reflection mode.
• Perform usual operations such as save, open, zoom, rescale...
• Select features specific to Fourier transform spectrometry: choose among spectrum or interferogram averaging, apodization, look and save the interferograms, etc.

The FTIR Rocket is also delivered with a free API that allows you to control the spectrometer with custom code via our DLLs. Examples are available for the following languages:

• C++
• C#
• Labview
• Matlab