Laser-based modulation-interference microscopy of optical surfaces

A new version of the modulation interference microscope with a long-path coordinate stage on aeromagnetic guides has been developed that can displace the microscope with nonrectilinearity no greater than 0.1 µm on a path length of up to 300 mm. The given modification of the microscope can be used to investigate the surface of large optical items having dimensions up to 300 × 300 × 100 mm with a resolution of 0.1 nm along the vertical and 10–100 nm in the sample plane. The design and operating principles of the main modules of the microscope are considered. Examples are used to show that the microscope thus developed has possibilities and advantages when optical surfaces are being investigated.