Polarized light imaging apparatus and methods thereof for separating light from a surface of a sample its deeper diffuse layers

Abstract

A polarized light imaging apparatus for separating light from a superficial single-scattering layer of a sample and its deeper diffuse layer as a function of space is disclosed. The apparatus has a light source for producing light beams; an illumination optic coupled to the light source for guiding the light beams towards the sample; a linear polarizer coupled to the illumination optic; a non-total internal reflection (TIR) birefringent polarizing prism (BPP) communicatively coupled to the sample to maximize a refraction difference between ordinary waves and extraordinary waves of light returning from the sample; and a detection optic unit coupled to the non-TIR BPP for guiding the light waves returning from the sample towards a single polarization sensitive sensor element.

1 - 17 . (canceled) 
     
     
         18 . A polarization difference imaging (PDI) apparatus comprising:
 a light source, an illumination optic, and a linear polarizer, that are jointly configured to emit linearly-polarized light towards a sample;   a non-total internal reflection (TIR) birefringent polarizing prism (BPP) that is:
 positioned to receive a light beam reflected from the sample responsive to the emitted linearly-polarized light, and 
 configured to separate the received light beam into two differently-polarized beams that exit the non-TIR BPP from two different locations; 
   a sensor coupled to an objective lens, such that the two differently-polarized beams form two distinct images in two separate regions of the sensor, respective of the two different locations; and   a processing unit configured to compute a PDI image of the sample from the two distinct images.   
     
     
         19 . The PDI apparatus according to  claim 18 , wherein said non-TIR BPP is selected from the group consisting of: a Wollaston prism, a Nomarski prism, a Rochon prism, and a Senarmont prism. 
     
     
         20 . The PDI apparatus according to  claim 18 , wherein said non-TIR BPP comprises cemented birefringent crystals. 
     
     
         21 . The PDI apparatus according to  claim 18 , further comprising two or more aperture stops configured to regulate an amount of light returning from the sample towards said non-TIR BPP. 
     
     
         22 . The PDI apparatus according to  claim 18 , wherein the sample is a human tissue that has a surface, a superficial scattering layer, and a deep diffuse layer. 
     
     
         23 . A method for polarization difference imaging (PDI), comprising:
 emitting linearly-polarized light towards a sample, using a light source, an illumination optic, and a linear polarizer;   at a non-total internal reflection (TIR) birefringent polarizing prism (BPP):
 receiving a light beam reflected from the sample responsive to the emitted linearly-polarized light, and 
 separating the received light beam into two differently-polarized beams that exit the non-TIR BPP from two different locations; 
   using the two differently-polarized beams to form two distinct images in two separate regions of a sensor, respective of the two different locations, wherein the sensor is coupled to an objective lens;   operating a processing unit to compute a PDI image of the sample from the two distinct images.   
     
     
         24 . The method according to  claim 23 , wherein said non-TIR BPP is selected from the group consisting of: a Wollaston prism, a Nomarski prism, a Rochon prism, and a Senarmont prism. 
     
     
         25 . The method according to  claim 23 , wherein said non-TIR BPP comprises cemented birefringent crystals. 
     
     
         26 . The method according to  claim 23 , further comprising operating two or more aperture stops to regulate an amount of light returning from the sample towards said non-TIR BPP. 
     
     
         27 . The method according to  claim 23 , wherein the sample is a human tissue that has a surface, a superficial scattering layer, and a deep diffuse layer. 
     
     
         28 . The method according to  claim 27 , further comprising utilizing the PDI image to determine whether cancer has developed in the superficial scattering layer.