Interferometric System and Method of Measurement of Refractive Index Spatial Distribution
AssigneeVysoke Uceni Technicke V Brne
InventorsPavel KOLMAN, Radim CHMELIK
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Abstract
An interferometric system and a method of measurement of refractive index spatial distribution for use in digital holographic microscopy to observe samples in reflected as well as transmitted radiation or to observe luminescent samples comprises a first branch and a second branch with a plurality of optical elements. The first branch comprises a diffraction grating located in a plane optically conjugated with the object plane in order to create an achromatic hologram with spatial carrier frequency in the output image plane.
Claims16
A method of measuring refractive index spatial distribution of a luminescent sample in an interferometric system comprising an external source of radiation, a first branch and a second branch, a system of reflectors, and a detector arranged in an output image plane and connected to a computing unit, where the first branch comprises a first input imaging system and a first output imaging system, and the second branch comprises a second imaging system, wherein the first input imaging system and the second input imaging system are arranged on an axis z and against each other so that the first and second input imaging system have a mutual image plane in which the luminescent sample is arranged, and which is optically conjugated with the output image plane, the method comprising the steps of:
- (a) exciting luminescent particles contained in the sample using an external source of radiation, wherein the luminescent particles then emit radiation, wherein the emitted radiation passes through the first branch and the second branch and reaches the detector, where the radiation from each branch interferes with the radiation passing through the other branch;
- (b) recording a first interferogram on the detector and saving the first interferogram to a computing unit;
- (c) shifting the luminescent sample in a direction of the axis z;
- (d) recording a second interferogram and saving the second interferogram to the computing unit;
- (e) calculating an amplitude of waves emitted by the luminescent sample and a difference of phases between the radiation passing through the first branch and the second branch from the first and the second interferogram;
- (f) calculating a difference between the difference of the phases from the first interferogram and the difference of the phases from the second interferogram;
- and
- (g) calculating an average value of refractive index in volumetric element defined by a size of a picture element and a size of the shift of the luminescent sample along the axis z.
Interferometric system comprising an external source of radiation, a first branch and a second branch, a system of reflectors, and a detector arranged in an output image plane, where the first branch comprises a first input imaging system and a first output imaging system, and the second branch comprises a second input imaging system, wherein the first input imaging system and the second input imaging system are arranged on an axis z and against each other so that the first and second input imaging systems have a common object plane optically conjugated with the output image plane, wherein the system further comprises at least one diffraction grating located in a plane optically conjugated with the object plane to create an achromatic hologram with spatial carrier frequency in the output image plane.
Dependencies are inferred from the claim text.