研究目的

To present a distance-resolving Raman radar device based on a time-correlated CMOS single-photon avalanche diode line sensor that can measure the location of the target sample simultaneously with the normal stand-off spectrometer operation and suppress the background radiation dramatically by means of sub-nanosecond time gating.

研究成果

The technology concerned enables distance scanning with 3.75 cm resolution in order to derive the distance from the Raman sample simultaneously with the Raman spectrum. The CMOS technology makes it possible to integrate optical detectors and all the other electronics into the same die and, thus, sub-nanosecond gating can be achieved more conveniently than with traditional time-gated CCDs or ICCDs, in which gating of several nanoseconds is normally used. This allows us to further reduce the background noise and the fluorescence of the sample that has a nanosecond-scale lifetime. We believe that this technology could pave the way for a new kind of distance-resolving Raman radar device for applications in mining and explosive detection, where a compact stand-off device with a distance range of several metres is needed.

研究不足

The optics and SPAD sensor circuit of the Raman radar were originally optimized for measurements through the microscope objective with the same excitation and collection axis, the objective of the microscope were simply removed and the measurements were performed at what was optically a relatively poor performance level. In addition, the off-chip delay unit was needed here because cm-level gate position sweeping of this kind had not been needed in the previously designed Raman microscope.