Infrared spectral measurements have been used for a broad range of applications from the composition of gas and liquid mixtures to the analysis of trace components for gas purity analysis. With the recent directives from FDA that pharmaceutical and chemical processes should be monitored stage by stage ( process analytical technology (PAT)), the detection technique employed up to now lack the sensitivity and the rate speed to achieve the monitoring. With IR spectroscopy emerging as a detection techniques, it is seen that Mid -IR region is the spectral region where most of the fundamental structural information is produced. While near Infrared has found many broad applications in industrial process management, mid-IR spectroscopy provides more useful analytical data which is more suited for PAT’s applications.
Mid-IR spectroscopy is a linear spectroscopy method used for control analysis in the pharmaceutical and chemical industry. Mid-IR spectroscopy is similar to nonlinear spectroscopy since it also targets molecular vibrations.The vast majority of gaseous chemical substances exhibit fundamental vibrational absorption bands in the mid-infrared spectral region (≈ 2–25 μm), and the absorption of light by these fundamental bands provides a nearly universal means for their detection. Mid-IR spectroscopy is generally best suited for materials identification; process monitoring through increase or decrease of a functional absorption band or determination of a specific component in a mixture.
Genia Photonics’ synchronized laser system provides a solution to generate mid-IR frequencies. The outputs of both internal lasers are combined into a single output beam and the common electronics ensure that the pulse stream of each laser remains synchronized throughout the entire wavelength sweep cycle. The synchronized beam is then sent through a nonlinear crystal (DFG crystal) to generate the difference frequency output (DFG), hence achieving the Mid-IR frequencies corresponding to the targeted wavenumbers. One of the main advantage of the Mid-IR source is the fast tunability feature of the programmable laser. This feature allows the user to rapidly tune within a range of wavelengths in either sequential or arbitrary manner.