Infrared evanescent-field microscope using CO2 laser for reflectance measurement

We build the experimental set up using a CO2 laser as an infrared light source and a pyramid shaped tip made of Zinc Selenide (ZnSe) as a light probe to investigate the possibility of an infrared evanescent field microscope for infrared micro-spectroscopic application. We verified that the generated evanescent field at the top of the pyramid shaped tip changed to a propagation wave when the sample is placed at the near-field region of the probe tip. We observed a sample with a high resolution which exceeds the diffraction limit of a conventional infrared microscope. We also described other factor that affect the performance of the microscope.