A method of operating a display device comprising a drive circuit is disclosed. The drive circuit comprises a plurality of single grey-level channels, each comprising an input (412, 422), an output (418, 428) and a signal processor connected between the input and output. Each signal processor comprises a digital-to-analog converter (414, 424) and an operational amplifier (416, 426) having a voltage offset. The method comprises: converting a digital signal received at the input (412, 422) into an analog voltage (410, 420) at the output (418, 428) using each respective signal processor; switching between the analog voltage (410, 420) of each single grey-level channel using a switching circuit (430); receiving and analysing the analog voltages (410, 420) in a calibration subsystem (440), and individually compensating for the voltage offset of each op-amp (416, 426) based on the received analog voltage (410, 420) for that grey-level channel using the calibration subsystem (440).

Techniques disclosed herein relate to optical devices. Resins with different optical properties can be deposited in different areas to provide increased optical functionality. It can be difficult to design a single photopolymer material that meets several technical requirements. Different resins can be deposited on the same substrate to make a single film with spatially varying properties. Different resins can also be applied to different substrates in a stack. By using different resins, an optical component can be made that meets several technical requirements.

Techniques disclosed herein relate to optical devices. Resins with different optical properties can be deposited in different areas to provide increased optical functionality. It can be difficult to design a single photopolymer material that meets several technical requirements. Different resins can be deposited on the same substrate to make a single film with spatially varying properties. Different resins can also be applied to different substrates in a stack. By using different resins, an optical component can be made that meets several technical requirements.

The technology provides two or more spectrometers with substantially uniform focal lengths. A method includes adjusting a size of a first air gap associated with a first lens in order to modify a first focal length and securing a relative position of a first body and a second body of the first lens to set the first focal length at a first value for a first spectrometer. The method further includes adjusting a size of a second air gap associated with a second lens provided in a second spectrometer in order to modify a second focal length and securing a relative position of a first body and a second body of the second lens to set the second focal length at a second value for a second spectrometer. The first and second values are selected to render the first focal length substantially equal to the second focal length.

A device for producing a subwavelength hologram. The device comprises a metasurface layer attached to a substrate. The metasurface layer includes an array of plasmonic antennas that simultaneously encode both wavelength and phase information of light directed through the array to produce a hologram. The wavelength is determined by the size of the antennas, and the phase is determined by the orientation of the antennas.

A method and system for forming a holographic structure in a material. The holographic structure is configured to project a selected target image in the far field under illumination of the holographic structure by a laser. The method calculates a modified design for the holographic structure that encodes a unique identifier within the holographic structure for projecting the target image. The method modifies the material by mapping features corresponding to the modified design into the material so as to form the holographic structure. A basic check of the authenticity of the material is performed by checking whether a projected replica of the target image is as expected. A more detailed check of the authenticity of the material is performed by directly inspecting the features in the holographic structure.

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.

Provided is a method for acquiring an evaluation value that can suppress an influence caused by an orientation of an object to be evaluated on an evaluation value derived based on a phase image of the object to be evaluated. The method for acquiring an evaluation value includes generating a phase image showing a phase distribution of light transmitted through an object, deriving an evaluation value of the object based on the phase image, and correcting the evaluation value by using a correction coefficient determined in accordance with an orientation of the object in the phase image.

The technology provides two or more spectrometers with substantially uniform focal lengths. A method includes adjusting a size of a first air gap associated with a first lens in order to modify a first focal length and securing a relative position of a first body and a second body of the first lens to set the first focal length at a first value for a first spectrometer. The method further includes adjusting a size of a second air gap associated with a second lens provided in a second spectrometer in order to modify a second focal length and securing a relative position of a first body and a second body of the second lens to set the second focal length at a second value for a second spectrometer. The first and second values are selected to render the first focal length substantially equal to the second focal length.

A method of manufacturing a thin film optical apparatus includes providing a substrate and applying an alignment layer over the substrate. The alignment layer ranges from about 50 to 100 nm in thickness. The method includes imprinting a hologram with a desired optic pattern onto the alignment layer and applying at least one layer of mesogen material over the alignment layer.