In an optical scanning type tunneling microscope, reference light is prepared in addition to light used to be projected to a sample, and this reference light and also light picked up from an optical probe are caused to interfere with each other. As a result, phase information of light about a region...http://www.google.com.au/patents/US5508805?utm_source=gb-gplus-sharePatent US5508805 - Interferometer, optical scanning type tunneling microscope and optical probe
