A microscope manifesting a dynamic range of several microns and an axial (or height) resolution of 1nm is presented. It is based on the method of angle deviation due to nonfocal plane reflection and the application of surface plasmon resonance effect as well as the technique of heterodyne interferometry. The deviation angle and the induced phase difference between two rays are proportional to the departure from the focal plane. Using the common-path heterodyne interferometry to scan the specimen and measure the phase difference distribution, the surface profile would be obtained in real time.
We present a new microscopy technique that we call transmission angle deviation microscopy (TADM). It is based on common-path heterodyne interferometry and geometrical optics. An ultrahigh sensitivity surface plasmon resonance (SPR) angular sensor is used to expand dynamic measurement ranges and to improve the axial resolution in three-dimensional optical microscopy. When transmitted light is incident upon a specimen, the beam converges or diverges because of refractive and/or surface height variations. Advantages include high axial resolution (approximately 32 nm), nondestructive and noncontact measurement, and larger measurement ranges (+/- 80 microm) for a numerical aperture of 0.21 in a transparent measurement medium. The technique can be used without conductivity and pretreatment.
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