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An imaging, differential optical sectioning interference microscopy (DOSIM) system and method for measuring refractive indices and thicknesses of transparent thin-films. The refractive index and thickness are calculated from two interferometric images of the sample transparent thin-film having a ver

An imaging, differential optical sectioning interference microscopy (DOSIM) system and method for measuring refractive indices and thicknesses of transparent thin-films. The refractive index and thickness are calculated from two interferometric images of the sample transparent thin-film having a vertical offset that falls within the linear region of an axial response curve of optically sectioning microscopy. Here, the images are formed by a microscope objective in the normal direction, i.e., in the direction perpendicular to the latitudinal surface of the thin-film. As a result, the lateral resolution of the transparent thin-film is estimated based on the Rayleigh criterion, 0.61λ/NA.

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What is claimed is: 1. A method for measuring a transparent thin-film to determine refractive indices n and thicknesses d of the thin-films, comprising: measuring the transparent thin-film to obtain an optically sectioned axial response curve; translating the transparent thin-film along an optical

What is claimed is: 1. A method for measuring a transparent thin-film to determine refractive indices n and thicknesses d of the thin-films, comprising: measuring the transparent thin-film to obtain an optically sectioned axial response curve; translating the transparent thin-film along an optical axis until intensity from the transparent thin-film is within the linear region of the optically sectioned axial response curve; performing at least two measurements in the linear region of the axial response curve to obtain two or more independent intensity relationships; and calculating a refractive index and thickness of the thin-film based on the independent intensity relationships. 2. The method of claim 1, wherein optical sectioning is performed with one of a scanning confocal microscope and a non-scanning wide field optical sectioning microscope. 3. The method of claim 1, wherein an optical system is used to measure light reflected from the thin-film by using an optical element having a aperture (NA) of approximately 0.55. 4. The method of claim 3, wherein a lateral resolution of the optical element is approximately 0.61λ/0.55, wherein λ is the wavelength of illumination light. 5. The method of claim 4, wherein the optical element is one of an objective lens, a Fresnel zone plate and a graded-index lens. 6. The method of claim 3, wherein the optical system uses a narrow-band light source. 7. The method of claim 6, wherein the bandwidth of the light source is sufficiently narrow such that reflection light from upper and lower interfaces of the thin-film to be measured can interfere. 8. The method of claim 6, wherein the bandwidth of the light source is sufficiently narrow such that the coherence length of the illumination light is longer than a largest possible thickness of the thin-film. 9. The method of claim 8, wherein the coherence length is λ2/Δλ, where λ is the wavelength and Δλ is the bandwidth of illumination light. 10. The method of claim 6, wherein the narrow-band light source is one of a laser and a narrow-bandwidth component selected from a white-light source using a monochromator or interference filters. 11. The method of claim 1, wherein the intensity of reflection light, with the thin-film in the linear region of the optically sectioned axial response curve, is determined by at least one of a position of the thin-film, the refractive indices of the thin-film and its substrate and an interference effect from upper and lower interfaces of the thin-film. 12. The method of claim 1, said translating step comprising the step of recording intensity of reflection light via an optical detector while the thin-film is translated along the optical line within the linear region. 13. The method of claim 12, wherein said recording comprises at least detecting the intensity of reflection light point-by-point. 14. The method of claim 13, wherein said detection is achieved by using a single detector or by forming an image of the thin-film by using an array of detectors. 15. The method of claim 12, wherein the optical detector is one of a photodiode, a photo-multiplier tube (PMT), a photodiode array, a charge-couple device (CCD) and complementary metal-oxide-semiconductor (CMOS) camera. 16. The method of claim 1, wherein said performing step comprises establishing one measurement in the linear region of an axial response curve and establishing another measurement on the focal plane of the axial response curve. 17. The method of claim 16, wherein the focal point of the axial response curve is the peak of the curve. 18. An optical system for measuring a transparent thin-film to determine refractive indices n and thicknesses d of the thin-films, wherein the system is configured to implement a program code stored in a module to: measure the transparent thin-film to obtain an optically sectioned axial response curve; translate the optical thin-film along an optical axis until intensity from the optical thin-film is within the linear region of the optically sectioned axial response curve; perform at least two measurements in the linear region of the axial response curve to obtain two or more independent intensity relationships; and calculate a refractive index and thickness of the thin-film based on the independent intensity relationships. 19. The system of claim 18, wherein optical sectioning comprises one of scanning confocal microscopy and non-scanning wide field optical sectioning microscopy. 20. The system of claim 18, wherein the optical system measures light reflected from the thin-film by using an optical element having a high numerical aperture (NA). 21. The system of claim 20, wherein a lateral resolution of the optical element is approximately 0.61λ/NA, wherein λ is illumination wavelength of light. 22. The system of claim 21, wherein the optical element is one of an objective lens, a Fresnel zone plate and a graded-index lens. 23. The system of claim 18, wherein the optical system includes a narrow-band light source. 24. The system of claim 23, wherein the bandwidth of the light source is sufficiently narrow such that reflection light from upper and lower interfaces of the thin-film to be measured can interfere. 25. The system of claim 23, wherein the bandwidth of the light source is sufficiently narrow such that the coherence length of the illumination light is longer than the largest possible thickness of the thin-film. 26. The system of claim 25, wherein the coherent light is λ2/Δλ, where λ is the wavelength and Δλ is the bandwidth of illumination light. 27. The system of claim 23, wherein the narrow-band light source is one of a laser and a narrow-bandwidth component selected from a white-light source using a monochromator or interference filters. 28. The system of claim 18, wherein the intensity of reflection light, with the thin-film in the linear region of the optically sectioned axial response curve, is determined by at least one of a position of the thin-film, the refractive indices of the thin-film and its substrate and an interference effect from upper and lower interfaces of the thin-film. 29. The system of claim 18, wherein placement of the optical thin-film in the linear region of the optically sectioned axial response curve comprises recording an intensity of reflection light via an optical detector while the thin-film is placed in the linear region. 30. The system of claim 29, wherein said recording comprises at least detection of the intensity of reflection light, point-by-point. 31. The system of claim 30, wherein said system includes one of a single detector and array of detectors. 32. The system of claim 29, wherein the optical detector is one of a photodiode, a photo-multiplier tube (PMT), a photodiode array, a charge-couple device (CCD) and complementary metal-oxide-semiconductor (CMOS) camera. 33. The system of claim 18, wherein said performance comprises establishment of one measurement in a linear region of an axial response curve and the establishment of another measurement on the focal plane of the axial response curve. 34. The system of claim 33, wherein the focal point of the axial response curve is the peak of the curve. 35. A method for measuring an optical thin-film to determine refractive indices n and thicknesses d of the thin-films, comprising: measuring the optical thin-film to obtain an optically sectioned axial response curve; translating the optical thin-film along an optical axis until intensity from the optical thin-film is within the linear region of the optically sectioned axial response curve; performing at least two measurements in the linear region of the axial response curve to obtain two or more independent parameters; and calculating a refractive index and thickness of the thin-film based on the independent parameters. 36. The method of claim 35, wherein the independent parameters comprise one of polarization and phase relationships.