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Non-interferometric phase retrieval using refractive index manipulation

View Article: PubMed Central - PubMed

ABSTRACT

We present a novel, inexpensive and non-interferometric technique to retrieve phase images by using a liquid crystal phase shifter without including any physically moving parts. First, we derive a new equation of the intensity-phase relation with respect to the change of refractive index, which is similar to the transport of the intensity equation. The equation indicates that this technique is unneeded to consider the variation of magnifications between optical images. For proof of the concept, we use a liquid crystal mixture MLC 2144 to manufacture a phase shifter and to capture the optical images in a rapid succession by electrically tuning the applied voltage of the phase shifter. Experimental results demonstrate that this technique is capable of reconstructing high-resolution phase images and to realize the thickness profile of a microlens array quantitatively.

No MeSH data available.


The configuration of the experimental setup: P, polarizer; S, test sample; MO, microscope objective; PS, phase shifter.
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f3: The configuration of the experimental setup: P, polarizer; S, test sample; MO, microscope objective; PS, phase shifter.

Mentions: The experimental arrangement is exhibited in Fig. 3. A red LED with a low temporal coherence at a wavelength of 633 nm is used to uniformly illuminate the object. The incident LED light is polarized by a polarizer along the axis of the extraordinary ray (e-ray) axis of the LC. A microscope objective (Olympus, MPLAPON 50X, NA = 0.5) placed behind the object is used to focus the image field onto the camera (Nikon-D600) with 6016 × 4016 pixels and pixel pitch sizes of 6 μm. The LC phase shifter is put in between the lens and the camera. The image stack is obtained by tuning the applied voltage of the phase shifter. For measuring a birefringent object, a setup similar to the polarized optical microscope could be used. An analyzer is inserted between the object and the phase shifter and set parallel to the axis of the extraordinary ray. Then, the phase images are measured by rotating the polarizer prior to the object.


Non-interferometric phase retrieval using refractive index manipulation
The configuration of the experimental setup: P, polarizer; S, test sample; MO, microscope objective; PS, phase shifter.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5384217&req=5

f3: The configuration of the experimental setup: P, polarizer; S, test sample; MO, microscope objective; PS, phase shifter.
Mentions: The experimental arrangement is exhibited in Fig. 3. A red LED with a low temporal coherence at a wavelength of 633 nm is used to uniformly illuminate the object. The incident LED light is polarized by a polarizer along the axis of the extraordinary ray (e-ray) axis of the LC. A microscope objective (Olympus, MPLAPON 50X, NA = 0.5) placed behind the object is used to focus the image field onto the camera (Nikon-D600) with 6016 × 4016 pixels and pixel pitch sizes of 6 μm. The LC phase shifter is put in between the lens and the camera. The image stack is obtained by tuning the applied voltage of the phase shifter. For measuring a birefringent object, a setup similar to the polarized optical microscope could be used. An analyzer is inserted between the object and the phase shifter and set parallel to the axis of the extraordinary ray. Then, the phase images are measured by rotating the polarizer prior to the object.

View Article: PubMed Central - PubMed

ABSTRACT

We present a novel, inexpensive and non-interferometric technique to retrieve phase images by using a liquid crystal phase shifter without including any physically moving parts. First, we derive a new equation of the intensity-phase relation with respect to the change of refractive index, which is similar to the transport of the intensity equation. The equation indicates that this technique is unneeded to consider the variation of magnifications between optical images. For proof of the concept, we use a liquid crystal mixture MLC 2144 to manufacture a phase shifter and to capture the optical images in a rapid succession by electrically tuning the applied voltage of the phase shifter. Experimental results demonstrate that this technique is capable of reconstructing high-resolution phase images and to realize the thickness profile of a microlens array quantitatively.

No MeSH data available.