Optical harmonic microscope assembly and examination method

A method for microscopically examining a specimen formed of material which is relatively transparent to a predetermined fundamental frequency and to at least one harmonic of said fundamental frequency, said specimen having spatial modulation of its nonlinear susceptibility whereby to project harmonic light of impinging lased light at an angle which depends at least upon the frequency of said lased light, comprising:

• supporting said specimen on a specimen stage of a microscope, said microscope being formed to be optically operational with light of said harmonic frequency and including as its optical system, an objective lens constituted of material which is inert to lased coherent light of said fundamental frequency, an eyepiece, and a body member defining an optical path between said objective lens and said eyepiece;
• generating lased, coherent light of at least said fundamental frequency;
• thereafter, focusing said lased coherent light as an incident beam onto said specimen to illuminate part of said specimen;
• after generating said lased light, adjusting said optical system to focus said microscope on said illuminated part of said specimen and to dispose said optical path and said incident beam at a desired relative angle in a range of angles which is at least as broad as the range 0-90.degree. whereby said optical system produces an image of structure of said specimen defined by a harmonic of said fundamental frequency, said harmonic being produced at said structure;
• and
• blocking light of said fundamental frequency from traveling to said eyepiece.