Differential Holography technology measures the amplitude and/or phase of, e.g., an incident linearly polarized spatially coherent quasi-monochromatic optical field by optically computing the first derivative of the field and linearly mapping it to an irradiance signal detectable by an image sensor. This information recorded on the image sensor is then recovered by a simple algorithm. In some embodiments, an input field is split into two or more beams to independently compute the horizontal and vertical derivatives (using amplitude gradient filters in orthogonal orientations) for detection on one image sensor in separate regions of interest (ROIs) or on multiple image sensors. A third unfiltered beam recorded in a third ROI directly measures amplitude variations in the input field to numerically remove its contribution as noise before recovering the original wavefront using a numerical in algorithm. When combined, the measured amplitude and phase constitute a holographic recording of the incident optical field.

A method for observation of a sample, the sample comprising microorganisms immersed in a nontransparent culture medium, the culture medium being favorable to the development of the microorganisms, and the sample being arranged between a light source and an image sensor, includes illuminating the sample with the light source, the light source emitting light propagating along an axis of propagation; acquiring an image of the sample by the image sensor; and, from the image acquired, characterizing the microorganisms. Light travels along the microorganisms through the culture medium to the sensor.

A holographic display method includes calculating a hologram, displaying it on a spatial light modulator (SLM) and illuminating it with coherent light. The hologram includes hologram pixels each having a hologram pixel value. The hologram is calculated using steps including: performing the inverse Fourier transform of the product of an object field and a negative quadratic phase exponential representative of positive optical power; and restricting each calculated hologram pixel value to one of a plurality (greater than two) of allowable pixel values to form a constrained hologram, which is displayed on the SLM. Each light-modulating pixel of the SLM is operable in a plurality of light-modulation levels corresponding to the plurality of allowable pixel values. The SLM is illuminated with coherent light to form a replay field including conjugate images: a real holographic reconstruction and a virtual holographic reconstruction having greater intensity than that of the real holographic reconstruction.

Differential Holography technology measures the amplitude and/or phase of, e.g., an incident linearly polarized spatially coherent quasi-monochromatic optical field by optically computing the first derivative of the field and linearly mapping it to an irradiance signal detectable by an image sensor. This information recorded on the image sensor is then recovered by a simple algorithm. In some embodiments, an input field is split into two or more beams to independently compute the horizontal and vertical derivatives using amplitude gradient filters in orthogonal orientations) for detection on one image sensor in separate regions of interest (ROIs) or on multiple image sensors. A third unfiltered beam recorded in a third ROI directly measures amplitude variations in the input field to numerically remove its contribution as noise before recovering the original wavefront using a numerical in algorithm. When combined, the measured amplitude and phase constitute a holographic recording of the incident optical field.

The present invention provides a holographic imaging device and a holographic imaging method that have improved performance in which the influence of a refractive index of a cube-type beam coupler constituting an optical system is considered. The holographic imaging device 1 comprises the beam coupler 3 consisting of the cube-type beam splitter arranged between the object 4 and the image sensor 5 and the calculation reference light hologram generation unit 14 for generating an inline reference light hologram j.sub.L representing a light wave on the hologram plane 50 by performing a light wave propagation calculation including propagation inside the beam coupler 3, on a spherical wave emitted from the condensing point P2 of the inline spherical wave reference light L. The inline reference light hologram j.sub.L is a computer-generated hologram and used for generating an object light hologram g by removing component of the reference light L from a complex-amplitude inline hologram J.sub.OL representing the object light O and the inline spherical wave reference light L on the hologram plane 50.

Among other things, a method comprises imaging a sample displaced between a sensor surface and a surface of a microscopy sample chamber to produce an image of at least a part of the sample. The image is produced using lensless optical microscopy, and the sample contains at least blood from a subject. The method also comprises automatically differentiating cells of different types in the image, generating a count of one or more cell types based on the automatic differentiation, and deriving a radiation dose the subject has absorbed based on the count.

A method and apparatus for monitoring particulate concentrations in ambient air use digital in-line holography and automated digital algorithms to classify and determine mass density and other characteristics of particles within a determined mass and size range. An embodiment provides a sampling plate on which particles are deposited at locations which depend on sizes and masses of the particles. A digital in-line hologram of the sampling plate is processed to obtain information about the particles. The method and apparatus have example application to environmental monitoring.

A lensless holographic imaging system having a holographic optical element includes: a coherent light source for outputting a first light beam and a second light beam, wherein the first light beam irradiates a first inspection plane to form first object-diffracted light; a light modulator for modulating the second light beam into reading light having a specific wavefront; a multiplexed holographic optical element, wherein the first object-diffracted light passes through the multiplexed holographic optical element, and the reading light is input into the multiplexed holographic optical element to generate a diffracted light beam as system reference light; and an image capture device for reading at least one interference signal generated by interference between the first object-diffracted light and the system reference light. The lensless holographic imaging system has a relatively small volume and relatively high diffraction efficiency.

An imaging system includes a phase grating overlying a two-dimensional array of pixels, which may be thermally sensitive pixels for use in infrared imaging. The phase grating comprises a two-dimensional array of identical subgratings that define a system of Cartesian coordinates. The subgrating and pixel arrays are sized and oriented such that the pixels are evenly distributed with respect to the row and column intersections of the subgratings. The location of each pixel thus maps to a unique location beneath a virtual archetypical subgrating. Portions of the phase grating extend beyond the edges of the pixels array to interference pattern in support of Fourier-domain imaging.

Provided is a holographic microscope including an input optical system configured to emit polarized input beam, a first beam splitter configured to emit an object beam by reflecting a portion of the polarized input beam, and emit a reference beam by transmitting a remaining portion of the polarized input beam, a reference optical system configured to separate the reference beam into a first reference beam and a second reference beam, a camera configured to receive the first reference beam and the second reference beam and the object beam that is reflected by an inspection object, the camera including a micro polarizer array, wherein a first polarization axis of the first reference beam is perpendicular to a second polarization axis of the second reference beam.