The Impact of Array Detectors on Raman Spectroscopy

A number of important breakthroughs have occurred in recent years that are allowing Raman spectroscopy to take a place alongside other mainstream analytical methodologies as a routine and powerful analytical tool in both laboratory and process-control environments. Advances in stabilized diode lasers, volume-phase holographics, imaging polychromators, comprehensive databases, and advanced focal-plane detectors have been combined to provide a new generation of user-friendly, robust instrumentation. Focal-plane array detectors and, particularly today, the charge-coupled device (CCD) have made a significant contribution to overall system performance by providing simultaneous spectral integration, high quantum efficiency, and low readout noise.The limitations in sensitivity and detection-limit capabilities, a traditional problem in conventional Raman, have been dropped to parts per million and in some cases even below. Performance characteristics and tradeoffs found in modern CCDs will be reviewed. Several new devices and system architectures, including multiplier devices providing single photon detection capabilities and new hybrid imaging technology (HIT) capable of improved system performance and greatly reduced cost, are discussed. Other cutting-edge technologies for improved performance, reduced cost, and near-infrared and infrared detection are considered and future potential will be assessed.