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US 2021/0063718 A1Published application
Portable quantitative phase microscope for material metrology and biological imaging
AssigneeThe Chinese University of Hong Kong
InventorsRenjie ZHOU, Mengxuan NIU, Gang LUO
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Abstract
A quantitative phase microscopy (QPM) system and methods are provided for sample imaging and metrology in both transmissive and reflective modes. The QPM system includes a first illuminating beam propagating along a transmission-mode path and a second illuminating beam propagating along a reflection-mode path, a microscope objective lens disposed in the reflection-mode path, and a common-path interferometer comprising a diffraction grating, a Fourier lens, a pinhole, and a 2f system lens to collimate the reference beam and the imaging beam such that the collimated reference beam and imaging beam interfere with each other to form an interferogram at a final image plane.
Claims23
A system for quantitative phase imaging, the system comprising:
- an illuminating source that generates an illuminating beam;
- a fiber coupler having an input end coupled to the illuminating source to receive the illuminating beam, configured to provide a first illuminating beam to output from a first output end to propagate along a transmission-mode path and a second illuminating beam to output from a second output end to propagate along a reflection-mode path;
- a first linear polarizer disposed in the transmission-mode path to receive the first illuminating beam from the fiber coupler and configured to linearly polarize the first illuminating beam before illuminating a sample;
- a second linear polarizer disposed in the reflection-mode path to receive the second illuminating beam from the fiber coupler and configured to linearly polarize the second illuminating beam;
- a half-wave plate disposed in the reflection-mode path to receive the second illuminating beam from the second linear polarizer and configured to rotate the polarization of the second illuminating beam to about 0 degree along a horizontal axis;
- a polarization beam splitter (PBS) disposed in the reflection-mode path to receive the second illuminating beam from the half-wave plate and configured to divide incident elliptically polarized light into orthogonally polarized beams such that the horizontally polarized second illuminating beam is fully directed to an objective lens side;
- a quarter-wave plate disposed in the reflection-mode path to receive the second illuminating beam from the PBS and configured to rotate an imaging field polarization state by about 90° along a vertical axis such that the second illuminating beam only goes along a right-hand side port of the PBS before forming an image;
- a microscope objective lens disposed in the reflection-mode path to receive the second illuminating beam from the quarter-wave plate and transmit the second illuminating beam to the sample and receive a third illuminating beam formed by the second illuminating beam reflected by the sample;
- the microscope objective lens being disposed to receive the first illuminating beam propagating from the transmission-mode path and transmitting through the sample for imaging;
- a tube lens disposed to receive the third illuminating beam from the PBS;
- and
- a common-path interferometer system disposed to receive the third illuminating beam from the tube lens, the common-path interferometer system comprising:
- a diffraction grating disposed in an intermediate image plane and configured to generate beams of multiple image orders, wherein a 0th diffraction order beam is configured to be an imaging beam and a 1st diffraction order beam is configured to be a reference beam;
- a Fourier lens disposed to receive both the 0th diffraction order beam and the 1st diffraction order beam and configured to focus them down by a predetermined focal length;
- a pinhole disposed in the Fourier plane to receive the 1st order beam, configured to be a low-pass filter for the 1st order beam;
- and
- a 2f system lens disposed to receive the imaging beam from the Fourier lens and the reference beam from the pinhole, configured to collimate the reference beam and the imaging beam such that the collimated reference beam and the imaging beam interfere with each other to form an interferogram at a final image plane.
14 more elements
A method for obtaining a quantitative phase image of a sample, the method comprising:
- generating an illuminating beam by an illuminating source;
- splitting the illuminating beam, by a fiber coupler, into a first illuminating beam to propagate along a transmission-mode path and a second illuminating beam to propagate along a reflection-mode path;
- linearly polarizing the first illuminating beam by a first linear polarizer disposed in the transmission-mode path;
- linearly polarizing the second illuminating beam by a second linear polarizer disposed in the reflection-mode path;
- rotating the polarization of the second illuminating beam to about 0 degree along a horizontal axis by a half-wave plate disposed in the reflection-mode path to receive the second illuminating beam from the second linear polarizer;
- dividing, by a polarization beam splitter (PBS) disposed in the reflection-mode path, the incident elliptically polarized light from the half-wave plate into orthogonally polarized beams such that the horizontally polarized second illuminating beam is fully directed to an objective lens side;
- rotating, by a quarter-wave plate, an imaging field polarization state by about 90° along a vertical axis such that the second illuminating beam only goes along a right-hand side port of the PBS before forming an image, wherein the quarter-wave plate is disposed in the reflection-mode path to receive the second illuminating beam from the PBS and configured to;
- transmitting, by a microscope objective lens, the second illuminating beam to the sample and receiving a third illuminating beam formed by the second illuminating beam reflected by the sample and the first illuminating beam transmitted through the sample for imaging, wherein the microscope objective lens is disposed in the reflection-mode path to receive the second illuminating beam from the PBS;
- receiving, by a tube lens, the third illuminating beam from the PBS and providing the third illuminating beam for the common-path interferometry;
- and
- performing a common-path interferometry by:
- generating beams of multiple image orders by a diffraction grating disposed in an intermediate image plane, wherein a 0th diffraction order beam is configured to be an imaging beam and a 1st diffraction order beam is configured to be a reference beam;
- focusing, by a Fourier lens, both the 0th diffraction order beam and the 1st diffraction order beam down by a predetermined focal length;
- low-pass filtering for the 1st order beam by a pinhole disposed in the Fourier plane;
- and
- collimating, by a 2f system lens, the reference beam and the imaging beam such that the collimated reference beam and the imaging beam interfere with each other to form an interferogram at a final image plane, the 2f system lens being disposed to receive the imaging beam from the Fourier lens and the reference beam from the pinhole.
13 more elements
Dependencies are inferred from the claim text.