A rotational geometric phase hologram has geometric phase optical elements (GPOEs) serially cascaded along a common optical axis to form a GPOE cascade used for receiving a linearly-polarized light beam and generating output light beams at an exit surface of the last GPOE. Interference occurred in the output light beams creates a polarization interference pattern on the exit surface. A photoalignment substrate, when positioned in close proximity to the exit surface, records the pattern. Advantageously, each GPOE is rotatable about the common optical axis. Respective rotation angles of the GPOEs are determined according to a spatially-varying linear polarization orientation distribution selected to be generated for the polarization interference pattern. Particularly, the respective rotation angles are reconfigurable to provide the periodicity required for the spatially-varying linear polarization orientation distribution over a range of allowed periodicities while keeping the periodicity of spatially-varying optic axis orientation distribution of each GPOE to be fixed.

Method and system for lensless, shadow optical imaging. Formation of a hologram shadow image having higher spatial resolution and lower noise level is accomplished by processing image information contained in multiple individual hologram shadow image frames acquired either under conditions of relative shift between point light source and the detector of the system or under stationary conditions, when system remains fixed in space and is devoid of any relative movement during the process of acquisition of individual image frames.

A rotational geometric phase hologram has geometric phase optical elements (GPOEs) serially cascaded along a common optical axis to form a GPOE cascade used for receiving a linearly-polarized light beam and generating output light beams at an exit surface of the last GPOE. Interference occurred in the output light beams creates a polarization interference pattern on the exit surface. A photoalignment substrate, when positioned in close proximity to the exit surface, records the pattern. Advantageously, each GPOE is rotatable about the common optical axis. Respective rotation angles of the GPOEs are determined according to a spatially-varying linear polarization orientation distribution selected to be generated for the polarization interference pattern. Particularly, the respective rotation angles are reconfigurable to provide the periodicity required for the spatially-varying linear polarization orientation distribution over a range of allowed periodicities while keeping the periodicity of spatially-varying optic axis orientation distribution of each GPOE to be fixed.

The present disclosure provides an anticounterfeiting system based on optical technology that verify the authenticity of protected cinema screens. The optical technology includes taggants embedded or attached to the screen and an optical readout system that can interrogate the taggant layer and receive the taggant output. The taggants are capable of reflecting a pattern that unambiguously demonstrates that the screen contains the taggant. The taggants are covert because they are not visible under normal lighting conditions or during cinema operation, but are detected when interrogated by the optical readout system.

A light detection and ranging, LiDAR, system arranged to make time of flight measurements of a scene. The LiDAR system comprises a holographic projector comprising: a spatial light modulator arranged to display light modulation patterns, each light modulation pattern comprising a hologram and a grating function having a periodicity; a light source arranged to illuminate each displayed light modulation pattern in turn; and a projection lens arranged to receive spatially modulated light from the spatial light modulator and project a structured light pattern corresponding to each hologram onto a respective replay plane. The LiDAR system further comprises a system controller arranged to receive distance information related to the scene and output to the holographic projector a control signal corresponding to the distance information. The holographic projector is arranged to use the control signal to determine a parameter for projection of a subsequent structured light pattern.

Method and system for lensless, shadow optical imaging. Formation of a hologram shadow image having higher spatial resolution and lower noise level is accomplished by processing image information contained in multiple individual hologram shadow image frames acquired either under conditions of relative shift between point light source and the detector of the system or under stationary conditions, when system remains fixed in space and is devoid of any relative movement during the process of acquisition of individual image frames.

An apparatus and method are disclosed for actinic inspection of semiconductor masks intended for extended ultraviolet (EUV) lithography, or similar objects, with feature sizes less than 100 nm. The approach uses a coherent light source with wavelength less than 120 nm. Inside a vacuum system, an optical system directs the light to an object, i.e., the mask or mask blank, and directs the resulting reflected or transmitted light to an imaging sensor. A computational system processes the imaging sensor data to generate phase and amplitude images of the object. The preferred imaging modality, a form of digital holography, produces images of buried structures and phase objects, as well as amplitude or reflectance images, with nanometer resolution less than or equal to the feature size of the mask.

Method and system for lensless, shadow optical imaging. Formation of a hologram shadow image having higher spatial resolution and lower noise level is accomplished by processing image information contained in multiple individual hologram shadow image frames acquired either under conditions of relative shift between point light source and the detector of the system or under stationary conditions, when system remains fixed in space and is devoid of any relative movement during the process of acquisition of individual image frames.

Method and system for lensless, shadow optical imaging. Formation of a hologram shadow image having higher spatial resolution and lower noise level is accomplished by processing image information contained in multiple individual hologram shadow image frames acquired either under conditions of relative shift between point light source and the detector of the system or under stationary conditions, when system remains fixed in space and is devoid of any relative movement during the process of acquisition of individual image frames.

An illumination system is arranged to output a light beam for illuminating a scene. The system comprises a spatial light modulator arranged to receive incident light, and to output light comprising a first component and a second component. The first component comprises incident light that is output without modulation by the spatial light modulator. The second component comprises incident light that is spatially-modulated according to a hologram and output by the spatial light modulator. A control device is operable to control the proportion of light output by the spatial light modulator that corresponds to the second component.