Raman spectroscopy is an analytical technique that non-invasively provides “chemical fingerprinting” information with high degree of specificity and sensitivity for medical/biological diagnostics. However, to avoid autofluorescence background signals, the measurements need to be carried out in the Near Infrared (NIR), where Raman scattering efficiency is low (proportional to λlaser-4). This provides challenges in terms of both detection sensitivity and minimisation of diagnostics time. Traditional high NIR sensitivity Si-based detectors suffer from elevated dark current, which can be minimised through cooling, but at the expense of a competing blue-shifting of sensor Quantum Efficiency (QE). Low Dark Current Deep-Depletion (LDC-DD) CCD technology first introduced by Andor minimises the need for deep-cooling, preserving QE for maximum detection capability and achieving higher signal-to-noise more quickly. The origins of this limitation of Si-based sensors and Andor’s technical solution will be explored. Additionally, the configurability of Andor’s spectrographs for researchers designing custom-built Raman and/or multi-diagnostics spectroscopy systems will be discussed. This instrumentation can facilitate new experiments which were not previously possible to enable new scientific breakthroughs. Higher selectivity, sensitivity, and rapidness of data acquisition offers faster sample screening, better clinical diagnostic measurements and minimisation of patient discomfort.
|