Excitation Laser Selection in the AIRsight Infrared Raman Microscope ―An Evaluation of UV-Degraded Plastics―

User Benefits

- The AIRsight infrared Raman microscope comes with two excitation lasers that can be selected to best suit samples. - Its 785 nm laser enables effective analysis of samples affected by fluorescence. - A photo-bleaching time can be set to reduce the influence of fluorescence.

Introduction

In Raman spectroscopy, the scattering intensity is inversely proportional to the fourth power of the excitation laser wavelength (Rayleigh’s scattering law). Therefore, the intensity of the Raman signal depends on the wavelength of the laser. Shorter wavelengths are typically used to obtain stronger signal intensities, but that can also result in fluorescence. Fluorescence emitted by a sample when absorbing incident UV-visible light from a short wavelength laser can obscure weaker Raman signals. In such cases, longer wavelength lasers that induce less fluorescence can reduce the influence of fluorescence. The AIRsight infrared Raman microscope system is equipped with 532 nm and 785 nm lasers as standard, allowing the user to select the laser wavelength that best suits a sample. This article presents the results of a measurement that used the two lasers in AIRsight to evaluate UV-degraded plastics. When evaluated by FTIR spectroscopy, the spectral shape of plastics is known to change when they are damaged by UV irradiation. More information on this topic can be found in Application News 01-00001.

12 de septiembre de 2023 GMT