Quantative phase imaging microscope and method and apparatus performing the same

1. Apparatus for selectively generating a plurality of scattered radiation patterns at an image plane of an optical microscope, comprising:

at least one lens element;

a liquid crystal display (LCD) array, wherein the LCD array comprises a plurality of pixel elements arranged in a grid layout, said array being connectable to a processing element adapted to selectively control a transmittance of each pixel in the grid layout; and

a housing comprising a body portion supporting the LCD array and lens element in a predetermined spaced apart relationship.

2. The apparatus as claimed in claim 1 , wherein the processing element is adapted to switch each pixel in the grid layout INTO an on/or -off state.

3. The apparatus as claimed in claim 2 , wherein, in the on state a pixel element is substantially transparent to optical radiation and in the off state a pixel element is substantially opaque to optical radiation.

4. The apparatus as claimed in 1 , wherein the arrangement of on/off pixel elements in the grid array provides a pixel pattern.

5. The apparatus as claimed in 1 , wherein the processing element comprises a PC or laptop.

6. A microscope, comprising:

a source of optical radiation;

a sample holder arranged to support a target object at a sample plane;

an objective lens housing;

a tube lens element; and

a detector array for detecting an intensity of radiation scattered by the target object at an image plane; wherein

the objective lens housing comprises a body portion supporting a liquid crystal display (LED) array and at least one lens element in a predetermined spaced apart relationship wherein the LCD array comprises a plurality of pixel elements arranged in a grid layout, said array being connectable to a processing element adapted to selectively control a transmittance of each pixel in the grid layout.

7. A method of providing image data for constructing an image of a region of a target object, comprising the steps of:

providing at least partially coherent optical radiation at a target object;

via at least one detector, detecting an intensity of radiation scattered by the target object with a liquid crystal display (LCD) array, providing a first pixel pattern, located between the target object and the detector;

subsequently, via the at least one detector, detecting an intensity of radiation scattered by the target object with the LCD array providing a further pixel pattern; and

selectively controlling a transmittance of the LCD array to provide the first pixel pattern and the further pixel pattern;

providing image data responsive to at least the intensity detected when the LCD array provides the first and further pixel patterns.

8. The method as claimed in claim 7 , wherein said step of providing said image data comprises the steps of:

estimating a wave function at a plane of the LCD array; and

iteratively re-estimating said a wave function; whereby

an accuracy of a running estimate of said a-wave function is improved with each iteration.

9. The method as claimed in claim 8 , further comprising the steps of:

multiplying the estimated a wave function by an array function indicating at least one characteristic of the pixel pattern provided by the LCD array;

providing an exit wave function responsive to a result of said multiplication;

propagating the exit wave function to provide an estimate of an expected scattering pattern; and

correcting at least one characteristic of said expected scattering pattern according to a detected intensity.

10. The method as claimed in claim 9 , wherein said corrected expected scattering pattern is corrected according to:

{circumflex over (R)} k ( υ )=√{square root over ( R k ( υ ))}exp( j∠R′ k ( υ ))

where {circumflex over (R)} k ( υ ) is a corrected wave function, √{square root over (R k ( υ ))} is the known plane 2 amplitude and R′ k ( υ ) is the guessed plane 2 phase.

11. The method as claimed in claim 10 , wherein propagation is calculated according to:

R k ′( v )= T[D k ( u )]  (3)

where R k ′(v) is guessed wave function in plane 2, T indicates a transformation and D k (u) is the guessed plane 1 wave function.

12. The method as claimed in claim 10 , wherein said inverse propagation is calculated according to:

ψ′ k ( u )= T −1 [{circumflex over (R)} k ( υ )]

where ψ′ k ( u ) is a guessed wave function in plane 1,

T −1 illustrates an inverse transformation procedure and {circumflex over (R)} k ( υ ) is a corrected wave function in plane 2.

13. The method as claimed in claim 8 , further comprising the steps of:

terminating the iteration process when a predetermined event occurs; and

subsequently estimating an object function indicating at least one characteristic of a region of the target object.

14. The method as claimed in claim 13 , further comprising the steps of estimating the object function by propagating a current running estimate of said a wave function extant when the iteration process is terminated.

15. The method as claimed in claim 13 , wherein said predetermined event comprises the number of iterations satisfying a predetermined condition or a calculated sum squared error satisfying a predetermined condition.

16. The method as claimed in claim 13 , wherein said step of propagating comprises a Fourier transformation when the detected intensity is detected at the far field or a Fresnel propagation when the at least one detector is at a distance from said LCD array where Fresnel diffraction dominates.

17. The method as claimed in claim 8 , further comprising the steps of:

inverse propagating the corrected expected scattering pattern to provide an updated exit wave function; and

updating the running estimate of said a wave function responsive to said updated exit wave function according to the function:

D k +1( u )=α L k ( u ) {circumflex over (ψ)} k ( u )+(1α L k ( u )) D k ( u )

where α is a feedback, D k+1 (u) is a running estimate of said a wave function, D k (u) is a preceding estimate of said a wave function or is unity when there is no preceding estimate, ψ k (u) is a corrected guess at an exit wave function and L k (u) is the current liquid crystal display (LCD) pixel pattern.

18. The method as claimed in 17 , further comprising the steps of selecting said further pixel pattern so that a transmittance area determined by said first pixel pattern overlaps at least partially with a further transmittance area determined by the further pixel pattern in a second position.