Abstract

Total internal reflection microscopy (TIRM) has been shown to be a useful tool for the study of substrate surfaces.¹ The surface under investigation is illuminated from within by a laser beam incident on the surface at an angle beyond the critical angle. A microscope focused on the surface collects only light scattered from substrate defects. TIRM can also be a sensitive detector of scatter from a coating on the substrate surface. This scatter may be related to the microstructure or surface roughness of the coating. The degree of scatter from the coating depends on the incident angle of the illuminating beam. A configuration is presented for a TIRM system which allows the incident angle to be varied without affecting the position of the beam on the sample. This arrangement is also independent of the focusing adjustment of the microscope and thus it can accommodate substrates of various thicknesses.

© 1989 Optical Society of America