Every channel is equipped with a separate optical filter by default. The channels are optically and electrically separated from each other. Of particular importance to the user are the number of channels and the area to be illuminated.

The 6 mm aperture is available as a two-channel detector and, now, also as a three-channel detector. In two-channel detectors all standard options are available with the exception of the "low micro” option. In three-channel detectors only the JFET model is available. The 9.5 mm aperture is available with 2, 3, or 4 channels and most of the standard options. At this aperture, the model with the integrated operational amplifier is thermally compensated and offers the "low micro” option on a standard basis. Thus, this aperture features the maximum configuration.

These detectors are based on an integrated reflecting beam splitter. During the product development the user has to take care of an almost collimated illumination (full angle < 14°). Originally, these detectors were developed to eliminate errors in the symmetry of measurement systems. Dirt in the optical path of a planar detector results in a quotient change of the signals by two channels. The dirt impairs the signal from each channel differently. This is not so with the 3D-type detectors. If, for instance, half of the aperture is covered, the signal level of each channel is cut in half. The quotient, however, remains constant. This was the original intention of the 3D structure (beam splitter sensors). In addition to the symmetry advantage, more and more customers benefit from the secondary effects of this concept: Because it is possible to make a separate measurement in four channels, despite the small aperture of 2.8 mm, many users take advantage of the fact that smaller cuvette diameters can be applied to facilitate quicker measurement with less measuring gas. The 3D components are very complex and somewhat of a flagship of InfraTec’s sensors. That is why in the course of product care it became their intention to use the OPV version for these components on a standard basis as well. Thermal compensation and the "low micro” option are currently not available for the 3D series components.

After a long developmental process this component is ready for series production. It features all the advantages of the 3D model but is limited in its wavelength range (3.0-4.1 µm and 3.9-5.0 µm). The tunable filter is advantageous whenever more than four interference filters are needed or customer-specific wavelengths have to be implemented in low volume. One can look at this component as a spectrometer building block. An evaluation kit is available as well.

One example of a multi-element detector is the 3x3 element array with integrated optics and an operational amplifier. The PIA-903 detector model was designed for safety applications. The user can obtain additional information about the direction of the infrared source. In fact, with two detectors it is possible to determine the spatial position. The second detector in this category is an open 30-element line which was developed for THz detection inside a vacuum.