Multi wavelength multiplexing for quantitative interferometry
AssigneeRamot at Tel-Aviv University Ltd.
InventorsNatan Tzvi SHAKED, Nir TURKO
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Abstract
The present invention relates to a new interferometric module which may be implemented as holographic/interferometric portable optical setups that are based on the interferometry with multiple wavelengths acquired simultaneously, without changing the imaging parameters, such as the magnification and the resolution, and recording the quantitative complex wave front (i.e. amplitude and phase) imaging in several wavelengths simultaneously. This may be used for multiple-wavelength phase unwrapping, for recording higher or optically thicker samples or for spectroscopic holography, without loss of camera frame rate due to wavelength scanning.
Claims23
An off-axis interferometric module comprising a light directing optical arrangement for directing light to an optical detector, wherein the light directing optical arrangement is configured for defining at least two substantially overlapping optical paths towards the optical detector, the light directing optical arrangement comprising:
- at least one wavelength selective filter, configured for receiving a multiple-wavelength light beam having a modulated complex wave front and having at least two spectral bandwidths and separating the multiple-wavelength modulated beam into at least two wavelength-separated beams, each defining N different wavelength channels;
- at least two reflecting surfaces defining a certain angle with respect to each other and positioned at the output of said wavelength selective filter;
- each reflecting surface being configured for receiving and rotating each wavelength-separated beam of each wavelength channel at a certain angle and back reflecting each wavelength-separated beam towards the detector through a beam combiner being configured for receiving and combining reflections of each wavelength-separated beam with a reference beam to produce at least two output combined beams propagating along said at least two substantially overlapping optical paths;
- said at least two output combined beams being thereby at least two off-axis overlapping interferograms to be optically multiplexed into a single off-axis interferogram, containing interference fringe orientation in different directions.
A method for multiple wavelength multiplexing comprising:
- separating a multiple-wavelength beam being indicative of an image of a sample and having at least two spectral bandwidths into at least two wavelength-separated beams, each defining N different wavelength channels;
- creating a reference multiple-wavelength modulated beam and rotating each wavelength-separated beam of each wavelength channel at a certain angle and reflecting each wavelength-separated beam with an off-axis angle on a detector;
- simultaneously projecting at least two image plane amplitude and phase modulated beams of each wavelength-separated beam onto a detector;
- combining reflections of each wavelength-separated beam with a reference multiple-wavelength modulated beam to produce at least two output combined beams propagating along at least two substantially overlapping optical paths;
- said at least two output combined beams being thereby at least two off-axis overlapping interferograms to be optically multiplexed into a single off-axis interferogram containing interference fringe orientation in different directions;
- and
- acquiring a single multiplexed interferogram simultaneously from at least two wavelength channels in a single detector exposure.
Dependencies are inferred from the claim text.