During the scanning process of the grating monochromator, as the wavelength increases, the secondary and tertiary diffraction orders will superimpose onto the target spectrum, causing short-wave stray light to "pollute" the long-wave signal, resulting in distorted measurement results. The function of the filter wheel is to automatically switch to the corresponding long-wave transmission filter in different wavelength ranges to filter out higher-order spectra. The Sefan Optoelectronics 7IFW6A electric filter wheel has a spectral coverage range extending to 2800nm short-wave infrared, pre-installing 4 long-wave transmission filters, providing an automated stray light suppression solution for the wide-spectrum scanning system of ultraviolet-visible-near-infrared-shortwave infrared.
The 7IFW6A has 6 gears: the first gear is an idle gear, the second to fifth gears are pre-installed with 4 long-wave transmission filters, the sixth gear is a user reserved installation position, where custom filters such as narrowband and bandpass can be installed at will. Compared with 7IFW6 (185~1600nm, 3 pre-installed, 2 reserved positions) and 7IFW6B (185~5000nm, 5 pre-installed, no reserved positions), 7IFW6A achieves a balance between spectral coverage and flexibility - it extends the working wavelength from near-infrared to short-wave infrared at 2800nm, meeting the testing requirements of lead sulfide detectors, InGaAs detectors, etc. It also retains 1 empty position for users to expand as needed.
The filter specifications are Φ18mm, thickness 2mm, light transmittance aperture 17mm, compatible with mainstream filter sizes. The 4 pre-installed long-wave transmission filters cover the entire wavelength range of 185~2800nm in segments, automatically switching to the corresponding filter when the monochromator scans to different wavelength ranges, filtering out the interference of secondary and tertiary spectra step by step, improving the purity of monochromatic light. This is crucial for experiments sensitive to stray light such as material transmittance testing, detector spectral response calibration, fluorescence and Raman spectrum acquisition - clean monochromatic light can output reliable spectral data.
The product supports both electric automatic + handwheel manual dual modes. When used with Sefan monochromators, spectrometers, or data acquisition systems, the software realizes automatic zeroing and positioning, automatic filter wheel rotation during the entire spectral scanning process, without manual intervention, suitable for automated sequential testing; without the electric control scenario, it can directly rotate the handwheel to manually switch gears, facilitating optical path debugging and prototype construction. The precise stepping transmission structure ensures stable long-term repetitive positioning, and multiple switches do not cause optical path deviation.
The entire machine uses a black anodized aluminum alloy base, integrates a stepping motor and DB9 control interface, has a compact structure, and can be directly installed at the monochromator exit or the standard hole position of the optical platform. It seamlessly integrates with Sefan 7IMS/7IS series monochromators, 7ID series detectors, and 7IDA data acquisition systems, quickly building a complete optical testing system.
Application scenarios: university material and optoelectronics laboratories, used for ultraviolet-visible-near-infrared transmittance/reflectance testing of thin film materials; photovoltaic and optoelectronic device research, testing spectral response curves of silicon detectors, InGaAs detectors, lead sulfide detectors; environmental monitoring and gas analysis, building a wide-spectrum absorption spectrometer system; integration with semiconductor and optical detection equipment.
7IFW6A, with 2800nm short-wave infrared coverage, four pre-installed filter wheels, and automatic zeroing switching, builds a barrier for monochromatic light purity for wide-spectrum spectrometers, ensuring that every wavelength measurement data is true and reliable.
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