A LabVIEW based virtual instrument system for mid infrared laser spectroscopy measurements

The development of a virtual instrument (VI) interface to acquire spectroscopic measurements using a quantum cascade laser-based on LabVIEW (TM) is presented. The interface can enable mid-infrared laser spectroscopic data acquisition using a fast response mercury-cadmium-telluride (MCT) detector. The MCT is connected to an analog/digital converter card, and the data is displayed in a virtual high-speed oscilloscope. The VI processes the acquired data, displays the information, and saves it to a file through several operations using a "state machine" architecture. Transmission measurements of a polystyrene film were used to calibrate the system. They were compared to the National Institute of Standards and Technology-based FT-IR reference spectrum, showing excellent agreement. The system was tested with four different optical setups for IR Transmission, Diffuse Reflectance Infrared Spectroscopy, Reflection Absorption Infrared Spectroscopy, and Attenuated Total Reflection. The VI can be easily customized, allowing users to adapt it according to their specific laboratory needs.