Apparatus and methods for 3D-Scanless Holographic Optogenetics with Temporal focusing (3D-SHOT), which allows precise, simultaneous photo-activation of arbitrary sets of neurons anywhere within the addressable volume of the microscope. Soma-targeted (ST) optogenetic tools, ST-ChroME and IRES-ST-eGtACR1, optimized for multiphoton activation and suppression are also provided. The methods use point-cloud holography to place multiple copies of a temporally focused disc matching the dimensions of a designated neuron's cell body. Experiments in cultured cells, brain slices, and in living mice demonstrate single-neuron spatial resolution even when optically targeting randomly distributed groups of neurons in 3D.

Methods, devices and systems for improved fabrication and measurement of holographic elements are described. One example method includes directing a reference and an object beam toward a holographic material for formation of a diffraction grating in the holographic material, and blocking one of the reference or the object beams to prevent the beam from reaching the holographic material for at least a portion of time during which the diffraction grating is being formed. During the blockage of the beam, a power level of a diffracted beam associated with the reference or the object beam that is not being blocked is measured. Based on the measured power level, it is then determined whether a particular diffraction grating efficiency is reached. The described techniques enable real-time measurement of diffraction grating efficiency as the grating is being formed and enable improved fabrication of holographic elements hat must meet precise diffraction grating efficiency requirements.

A method and systems for simultaneous recording of superimposed holographic gratings for augmented reality devices are provided. The method includes: generating a beam by a single light source, directing the beam to a decoherence unit at a predetermined angle, forming at least two recording beams by the decoherence unit by splitting the beam, forming at least two recording channels in the decoherence unit to transmit the at least two recording beams and output them from the decoherence unit, output angles of each of the at least two recording beams being different, the at least two recording beams being non-interfering when leaving the decoherence unit, which is provided in accordance with at least one of: output times, spatial positions, polarization states, or spectral compositions of each of the at least two recording beams, illuminating a recording material layer and one master diffractive optical element/master holographic optical element (master DOE/HOE) comprising at least one preliminary formed diffraction/holographic grating by the at least two non-interfering recording beams, simultaneously forming at least two superimposed holographic gratings from the master DOE/HOE on or in the recording material layer, the formed superimposed holographic gratings having a same surface period, but a different spatial period.

Exemplary arrangements relate to methods for recording and reproducing holograms. A method of recording a hologram in a thresholded opto-magnetic medium (7) includes producing a collimated recording beam (1) with a pulsed laser. The intensity of the recording beam is selectively modulated by passage through a modulator (2). The recording beam is spatially shaped by passage through a shaping element (15). The shaped modulated recording beam is made convergent by passage through an aspheric lens (4). The convergent beam is deflected bidirectionally with a MEMS mirror (6) that is in operative connection with the modulator, such that multiple disposed locations on a surface of the medium are exposed to a constriction of the convergent shaped recording beam, causing a change in the medium in the locations. Reconstructing the hologram is carried out by illuminating the medium with a collimated laser beam and focusing with a lens, light from the illuminated medium onto a detection matrix. Additional methods of recording and reproducing holograms utilize alternative steps.

A holographic image generation system including a spatial light modulator; a light source; a temporal modulator; a light sensor and a demodulator. The spatial light modulator has pixels. The light source illuminates the spatial light modulator. The temporal light modulator modulates an output intensity of the light source over time to encode holographic data representing a hologram. The light sensor is associated with a spatial light modulator and receives light from the light source and generates a signal representative of the output intensity of the light source. The demodulator is connected to the light sensor to receive the signal. The demodulator decodes the signal to obtain the holographic data. The demodulator is connected to the spatial light modulator to set the pixels of the spatial light modulator in accordance with the holographic data to display the hologram ready for illumination by the light source to form a holographic reconstruction.

A method for three-dimensional imaging of a sample (302) comprises: receiving (102) interference patterns (208) acquired using light-detecting elements (212), wherein each interference pattern (208) is formed by scattered light from the sample (302) and non-scattered light from a light source (206; 306), wherein the interference patterns (208) are acquired using different angles between the sample (302) and the light source (206; 306); performing digital holographic reconstruction applying an iterative algorithm to change a three-dimensional scattering potential of the sample (302) to improve a difference between the received interference patterns (208) and predicted interference patterns based on the three-dimensional scattering potential; wherein the iterative algorithm reduces a sum of a data fidelity term and a non-differentiable regularization term and wherein the iterative algorithm includes a forward-backward splitting method alternating between forward gradient descent (108) on the data fidelity term and backward gradient descent (110) on the regularization term.

A plasma generator including: a femtosecond light source that generates a laser pulse beam; a processor that computes a computer generated hologram; a spatial light modulator that modifies the laser pulse beam in accordance with the computer generated hologram; a three dimensional scanner optically coupled to the spatial light modulator to direct the modified laser pulse beam to one or more focal points in air; and a lens that focuses the modified laser pulse beam. The modified laser pulse beam induces a light emission effect at a one or more focal points that can be visible, audible, and palpable.

The present disclosure relates to systems and methods for cell recognition. At least one embodiment relates to a method for recognizing cell. The method includes receiving an image of the cell. The method also includes performing edge detection on the image of the cell. Further, the method includes detecting ridges within the image of the cell. In addition, the method includes quantifying an internal complexity of the cell by gauging a contrast of the ridges with an average of a Laplacian on the detected ridges.

There is disclosed herein a method of light detection and ranging. The method comprises a first step of illuminating a scene with a first light pattern and monitoring for first light return from the scene with an array of detection elements. The method comprises a second step of obtaining first point cloud data from first parts of the scene where the first light return exceeds a first threshold value. The method comprises a third step of determining a second light pattern by reducing, such as substantially zeroing, the intensity of the first light pattern in the areas wherein first point cloud data was obtained. The method comprises a fourth step of illuminating the scene with the second light pattern and monitoring for second light return from the scene with the array of detection elements.

A design screen and at least one detection device with an image capturing device and a carrier medium are provided in an external lighting device for a motor vehicle. The carrier medium is a flat waveguide on which a coupling region and a decoupling region are provided. The carrier medium is adapted to the surface shape of the design screen. The coupling region and the decoupling region are each a holographic element. Light incident on the external lighting device from the surroundings is coupled into the carrier medium via the coupling region, is transported to the decoupling region by internal reflection in the waveguide, and is decoupled at the decoupling region. The image capturing device detects the decoupled light and provides image data which correlates to the detected light.