The instrument allows high sensitivity analysis to be carried out, based on a unique system that involves a highly efficient BHG (Blazed Holographic Grating) as well as a low-noise circuitry that includes a digital filter. For convenience and enhanced operability, the system is designed to run on an MS-Windows platform, providing an intuitive, graphical user interface. As a result, the operator can feel comfortable in a wide variety of applications raging from routine analysis to state-of-the-art research work.