The COMPOLYTICS^® ScanCorder platform extends inverted spectroscopy beyond reflectance measurements into fluorescence sensing.

Fluorescence measurements require a different optical configuration to that used for conventional reflectance sensing. A sample is illuminated at specific excitation wavelengths and the resulting fluorescence emission is detected at different wavelengths. The ScanCorder approach is particularly well suited to this principle, as its inverted spectroscopy architecture already employs individually controlled wavelengths in a sequential illumination scheme.

For fluorescence sensing, the selected illumination wavelengths can serve as the excitation bands, and several detection bands can be configured to capture the resulting emission. This allows for the creation of compact, application-specific measurement heads, where the wavelengths used for excitation and detection can be tailored to the optical characteristics of the target application.

Adaptations to the ScanCorder electronics and optical configuration were required to support excitation wavelengths in the UV range. First productive fluorescence measuring heads have been implemented with application-specific sets of excitation and detection bands.

From technology to application

The new capability has already been demonstrated through laboratory measurements conducted at several partners and customers. During the initial measurement campaign, bacteria and protein samples were examined under controlled laboratory conditions, and complementary spectral data was collected to support the development and optimisation of future sensor configurations.

This research is part of ongoing work into a multimodal optical sensor for chronic wound assessment that combines fluorescence and reflectance measurements within a single, handheld platform. These two techniques provide (partly) complementary information and may enable a more comprehensive characterisation of biological samples than either technique alone.

Application-specific optical sensing

One of the main advantages of this approach is its configurability, which is a fundamental feature of all ScanCorder sensor designs. Since excitation and detection are based on individually selectable wavelength bands, a fluorescence ScanCorder can be designed to match the spectral characteristics of a specific application.

This is particularly useful when only certain excitation and emission bands are relevant. This is often the case in real-world applications. Rather than conducting a full hyperspectral measurement, a compact, tailored sensor can focus on the wavelengths that provide the most useful information for the given application.

Therefore, fluorescence is a natural technological and business extension of the ScanCorder platform, complementing its well-established reflectance-based sensing capabilities. Although fluorescence applications are expected to be more specialised than the broader range of reflectance applications, the combination of compact hardware, configurable wavelength channels, and inverted spectroscopy offers great potential for application-specific optical sensing in biochemical and biomedical areas and beyond.

This development shows that different optical modalities can be integrated into a generic, handheld sensing platform capable of capturing complementary information according to the requirements of the underlying application, demonstrating the broader potential of the ScanCorder sensor architecture.

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This work was partly funded by the German Federal Ministry of Research, Technology and Space under project number 03WIR7311B.