Spectrally-encoded high-extinction polarization microscope and methods of use

Patent metadata

Field	Value
Publication number	US-2016154229-A1
Application number	US-201514963900-A
Country	US
Kind code	A1
Filing date	Dec 9, 2015
Priority date	Jun 9, 2013
Publication date	Jun 2, 2016
Grant date	—

Abstract

Described herein is a polarization microscope that uses spectral-encoding of the polarization state for cellular imaging. The spectral-encoded polarization microscope is both sufficiently fast for cellular imaging and is compatible with high extinction optics required to image molecular structures and assemblies. The spectral-encoded microscope allows for the polarization state of light presented to the specimen to sample discrete states over the entirety of the Poincaré sphere while simultaneously giving a null measurement of the observed cellular birefringence. Sampling over the entire Poincaré sphere allows the microscope to determine of specimen phase retardation due to both linear and circular birefringence. The spectral-encoded polarization microscope can be operated in a slightly off-null state that will improve signal-to-noise.

First claim

What is claimed is:

1 . A polarization microscope comprising:
a variable wavelength light source changing the wavelength of light; a first polarizer optically coupled to the variable wavelength light source, wherein the first polarizer transmits polarized light; a first retarder module optically coupled to the first polarizer, where the first retarder transforms the polarized light to a new polarization state as a function of wavelength, such that small changes in emission wavelength move the polarization state to new positions on the Poincare sphere; a specimen stage optically coupled to the first retarder module, wherein the specimen stage holds a specimen in the optical pathway of the light received from the first retarder module; a second retarder module optically coupled to the specimen stage, wherein the second retarder module is an opposite-signed retarder with respect to the first retarder module as to reverse the polarization transformation of light received from the specimen by an equal amount from the first retarder module; a second polarizer optically coupled to the second retarder module, wherein the second polarizer transmits a state that is orthogonal to the first polarizer; an optical capture device optically coupled to the second polarizer, wherein the optical capture device captures light passing through the second polarizer and captures images of the specimen after each change of wavelength of light.

2 . The polarization microscope of claim 1 , wherein the variable wavelength light source is capable of producing light having a wavelength from between about 350 nm to about 800 nm and changing emission wavelengths at a maximum speed of between 1 microsecond/wavelength and 5000 microseconds/wavelength.

3 . The polarization microscope of claim 2 , wherein the first polarizer and/or the second polarizer is a polarizing prism.

4 . The polarization microscope of claim 3 , wherein the first retarder module includes a first retarder, a second retarder, and a first wave plate; and the second retarders module includes a second wave plate, a third retarder, and a fourth retarder.

5 . The polarization microscope of claim 4 , wherein the first retarder is matched in thickness and optical retardation with the fourth retarder, and the second retarder is matched in thickness and optical retardation with the third retarder.

6 . The polarization microscope of claim 5 , wherein the first retarder, the second retarder, the third retarder, and the fourth retarder are selected from quartz or tellurium dioxide.

7 . The polarization microscope of claim 4 , wherein the first wave plate and the second wave plate are zero order retarders.

8 . The polarization microscope of claim 4 , wherein the degree of retardance of the retarders is based on the wavelength of the incident light.

9 . The polarization microscope of claim 3 , wherein the fast and slow axis of the third retarder are opposite to second retarder and the fast and slow axis of the fourth retarder is opposite to the first retarder.

10 . The polarization microscope of claim 3 , further comprising a first lens optically coupled between the first retarder module and the specimen stage; and a second lens optically coupled between the specimen stage and the second retarder module.

11 . The polarization microscope of claim 10 , wherein the optical capture device is a charged coupled device; and wherein the variable wavelength light source comprises a lamp housing including a xenon arc lamp illuminating an adjustable ellipsoidal mirror focused through an ultraviolet-blocking window and an exit slit; light exiting the exit slit passes to an adjustable flat mirror onto a beam block; the xenon arc lamp includes an arc lamp anode attached to a cooler and a ceramic insulating plate; the xenon arc lamp includes an arc lamp cathode connected to a cooler; the xenon arc lamp includes a plurality of position adjustment screws to position the xenon arc lamp; the arc lamp anode includes and the arc lamp cathode includes at least two high-voltage connections operably coupled to an external igniter and a power supply; and the lamp housing filled with a gas.

12 . The polarization microscope of claim 11 , wherein the light from the first retarder module passes through the specimen held on the specimen stage.

13 . The polarization microscope of claim 11 , wherein the light from the first retarder module is reflected off the specimen held on the specimen stage.

14 . A method of visualizing a specimen using a polarization microscope comprising:
placing the specimen on a specimen stage of a polarization microscope as described in claim 1 ; and obtaining images of the specimen at one or more wavelengths.

15 . The method of claim 14 , wherein obtaining images of the specimen comprises periodically changing the wavelength of light impinging on the specimen and capturing images of the specimen after each change of wavelength of light.

16 . The method of claim 15 , wherein each change of wavelength occurs in between 10 and 500 microseconds.

17 . The method of claim 16 , wherein imagining of the biological specimen is performed continuously over a time of at least about 2 seconds.

18 . The method of claim 17 , wherein the method further comprises modulating the polarization state of the light over the entire Poincare sphere by altering the wavelength of the light produced by the variable wavelength light source.

19 . The method of claim 18 , further comprising:
adjusting the transmission state of the first polarizer with respect to the second polarizer so that the first polarizer and the second polarizer are not orthogonal; and obtaining images of the specimen while the first polarizer and second polarizer are not orthogonal.

20 . The method of claim 19 , further comprising calibrating the polarization microscope by determining the orientation state of the light when the second polarized light rotator and the second retarder module are removed from the optical path; and determining the orientation state of the light comprises rotating the second polarizer through discrete angles and analyzing the data collected by the optical capture device.

Assignees

• Univ Texas

Inventors

• Milner Thomas E
• Yin Biwei
• Kuhn Jeffrey Russel

Classifications

• H04N23/56

  provided with illuminating means · CPC title

• H04N25/71

  Charge-coupled device [CCD] sensors; Charge-transfer registers specially adapted for CCD sensors · CPC title

• H04N5/2256

  Electricity · mapped topic

• G02B21/26

  Stages; Adjusting means therefor · CPC title

• G02B21/36

  arranged for photographic purposes or projection purposes (G02B21/18 takes precedence){or digital imaging or video purposes including associated control and data processing arrangements (image data processing per se G06T)} · CPC title