Method for observing a sample

Patent metadata

Field	Value
Publication number	US-10564602-B2
Application number	US-201615577129-A
Country	US
Kind code	B2
Filing date	May 26, 2016
Priority date	May 28, 2015
Publication date	Feb 18, 2020
Grant date	Feb 18, 2020

Abstract

A method for observing a sample includes illuminating the sample with a light source and forming a plurality of images, by an imager, the images representing the light transmitted by the sample in different spectral bands. From each image, a complex amplitude representative of the light wave transmitted by the sample is determined in a determined spectral band. The method further includes backpropagation of each complex amplitude in a plane passing through the sample, determining a weighting function from the back-propagated complex amplitudes, propagating the weighting function in a plane along which the matrix photodetector extends, updating each complex amplitude, in the plane of the sample, according to the weighting function propagated.

First claim

The invention claimed is:

1. A method for observing a sample, comprising:
i) illuminating the sample using a light source that produces a light wave that propagates along a propagation axis;
ii) acquiring, using a photodetector, a plurality of images of the sample, the images being formed in a detection plane, the sample being placed between the light source and the photodetector, each image of the plurality being representative of a light wave, transmitted by the sample under effect of the illumination, called the transmitted light wave, and each image of the plurality being acquired in a spectral band that is different from that of other images of the plurality;
iii) determining, based on each image respectively acquired in each spectral band, an initial complex amplitude of the transmitted light wave, in said each spectral band, in the detection plane;
iv) selecting a sample plane, in which the sample lies, and back-propagating each complex amplitude established in the detection plane, in said each spectral band, in order to determine a complex amplitude of the transmitted wave, in said each spectral band, in the sample plane;
v) calculating in said each spectral band, based on a plurality of complex amplitudes determined in step iv), a weighted sum of the complex amplitudes, or of logarithm functions thereof, or of argument functions thereof, in the sample plane, and calculating a weighting function, the weighting function being calculated using the weighted sum;
vi) propagating the weighting function to the detection plane so as to obtain, for at least one spectral band, a weighting function in the detection plane;
vii) updating at least one complex amplitude of the transmitted light wave, in a spectral band, in the detection plane, using the weighting function obtained, in the spectral band, in step vi); and
viii) repeating steps iv) to vii) until a stop criterion is reached,
wherein, in step vii), an argument function of the complex amplitude of the transmitted light wave, in a spectral band, in the detection plane, is calculated depending on an argument function of the weighting function determined, in the detection plane and in the spectral band, in step vi).

2. The method of claim 1 , wherein, in step iii), a modulus of the complex amplitude of the transmitted light wave in a spectral band is determined by normalizing the intensity of the image acquired by the photodetector, in the spectral band, by a reference intensity measured by the photodetector in the absence of sample.

3. The of claim 1 , wherein, in step iv), the complex amplitude in a sample plane, in a spectral a, is determined by applying a propagation operator to the complex amplitude, defined in the same spectral band, in the detection plane.

4. The method of claim 1 , wherein, in step vi), the weighting function, in the detection plane, is propagated by applying a propagation operator to the weighting function determined, in the sample plane, in step v).

5. The method of claim 1 , wherein, in step vii), a modulus of the complex amplitude of the transmitted light wave, in a spectral band, in the detection plane, is calculated depending on a modulus of the initial complex amplitude, in the spectral band.

6. The method of claim 1 , wherein, in stet v), the weighting function is common to all the spectral bands.

7. The method of claim 1 , wherein step v) further comprises determining a plurality of weighting functions, each weighting function of said plurality of weighting functions being associated with one spectral band.

8. The method of claim 1 , further comprising, following step viii):
ix) forming an image representative of a modulus or of an argument function of the complex amplitude of the wave transmitted by the sample, in the sample plane or in the detection plane, in at least one spectral band.

9. A device for observing a sample, comprising:
a light source configured to illuminate the sample;
a photodetector,
the sample being disposed between the light source and the photodetector,
the photodetector being configured to form a plurality of images, in a detection plane, of the light wave transmitted by the sample under effect of illumination by the light source, each image being obtained in a spectral band that is different from that of other images of the plurality; and
a processor, configured to process the plurality of images by executing instructions, programmed into a memory, which, when executed, implement the method of claim 1 .

Assignees

• Commissariat Energie Atomique

Inventors

• Allier Cedric
• Bordy Thomas
• Cioni Olivier
• Herve Lionel
• Morel Sophie

Classifications

• G03H2001/0471

  Object light being transmitted through the object, e.g. illumination through living cells · CPC title

• G03H2001/0454

  Arrangement for recovering hologram complex amplitude · CPC title

• G03H2222/13

  Multi-wavelengths wave with discontinuous wavelength ranges (G03H2222/18 takes precedence) · CPC title

• G03H2210/13

  Coloured object · CPC title

• G03H2001/2263

  Multicoloured holobject · CPC title