APPARATUS AND METHOD TO CONVERT A REGULAR BRIGHT-FIELD MICROSCOPE INTO A PS-QPI SYSTEM
An apparatus, system, and related methods for the conversion of a regular bright-field microscope into a PS-QPI (Polarization-Sensitivity and Quantitative Phase Imaging) microscope system. A regular bright-field microscope is converted by insertion of a polarizing element in the illumination path and a Fresnel biprism in the image space of the system. The converted system is suitable for real-time quantitative PS phase imaging in a broad number of biological applications aimed at understanding cell growth and dynamic changes occurring during physiological processes, as well as identification of cell/tissue screening and diagnosis.
1 . A system for converting a bright-field microscope into a polarization-sensitive quantitative phase imaging microscope (PS-QPI) system, comprising:
a PS-QPI module comprising a polarizing element and a Fresnel biprism, said polarizing element configured to be inserted into an illumination path of a bright-field microscope to orient a polarization state of an illumination source, and said Fresnel biprism configured to be inserted into an image space of said bright-field microscope;
wherein the polarizing element is configured to rotate in a controlled way to change the illumination source polarization state; and
wherein the Fresnel biprism is configured to generate two polarization preserving images of a magnified image.
2 . The system of claim 1 , further comprising a bandpass filter.
3 . The system of claim 1 , further comprising an afocal imaging system.
4 . The system of claim 3 , said afocal imaging system comprising two converging lenses.
5 . The of claim 1 , further comprising a sensor or detector.
6 . The system of claim 5 , wherein the sensor or detector is a two-dimensional detector configured to record an image to a computer.
7 . The system of claim 5 , wherein the sensor or detector is a CCD or CMOS configured to record an image to a computer.
8 . The system of claim 1 , wherein the illumination source is spatially and temporally coherent.
9 . The system of claim 1 , wherein the illumination source comprises a diode laser, gas laser, discharge tube, light-emitting diode with limited spectral bandwidth, a wide-band light source, or an incandescent and/or fluorescent light source with bandpass filters configured to limit spectral bandwidth.
10 . The system of claim 1 , wherein the polarizing element comprises a linear polarizer or a waveplate.
11 . The system of claim 1 , wherein the polarizing element is mounted in a rotational cage or mount.
12 . The system of claim 1 , wherein the Fresnel biprism is configured to generate two copies of a magnified image of a sample with some angle to each other.
13 . The system of claim 12 , wherein the Fresnel biprism comprises two prisms joined at respective bases.
14 . The system of claim 12 , wherein a digital hologram is formed by the coherent superposition or interference of the two copies of the magnified image.
15 . The system of claim 3 , said afocal imaging system comprising a first converging lens and a second converging lens with a common Fourier plane therebetween, and a pinhole located at the common Fourier plane.
16 . The system of claim 3 , wherein the afocal imaging system magnifies the image of a sample.
17 . The system of claim 15 , where the pinhole comprises a spatial filter configured to filter the medium and high frequency content of one of a pair of images generated by the Fresnel biprism.
18 . The system of claim 1 , further comprising:
a secondary polarization module comprising a second illumination source and a second polarizing element, wherein the secondary polarization module introduces a reflected image of the sample into an optical path; and
a beam splitter placed between the tube lens and the Fresnel biprism.