This disclosure describes an example architecture for providing a delay line for optical techniques. The delay line architecture includes a focusing element that has a focal axis disposed parallel to its length. The line of symmetry provided by the focal axis obviates path-length-dependent aberrations caused by the off-axis beam translations. The systems described herein also provide varying geometries of movable mirrors, including a galvanometer mirror and a rotating polygonal mirror. The systems and methods described herein also provide techniques for generating and detecting coherent Raman spectra using a picosecond probe pulse.

The head-up display device includes a display element that emits image light and a virtual image optical system. The virtual image optical system includes a lens unit and a free curved surface mirror disposed along the emission direction of the image light in this order from a position close to the display element. The display element is disposed with a tilting attitude with respect to the optical axis of the lens unit with an end on the housing aperture side in an emission surface being close to an incidence surface in the lens unit and with an end on the opposite side of the housing aperture in an emission surface being apart from an incidence surface in the lens unit. The lens unit has an optical characteristic of optically enlarging an optical path length difference according to a virtual image distance difference.

A system to adjust light path length comprising a digital light path length modulator, the digital light path length modulator comprising a polarization modulator to receive polarized light and to modulate a polarization of some or all of the polarized light. The system further comprising an optical path length extender (OPLE) having an entry surface and an exit surface, to direct the light entering the OPLE with a first polarization through the entry surface and along a first light path through the OPLE to exit through the exit surface, and to direct the light entering the OPLE with a second polarization through the entry surface and along a second light path through the OPLE to exit through the exit surface, the second light path through the OPLE having a light path length two or more times longer than the first light path length through the OPLE.

An optical module includes a base, a holding component, an optical element, and at least one detachable structure. The holding component is disposed on the base, in which a position of the holding component relative to the base along a first axial direction is adjustable. The optical element is disposed on the holding component. The detachable structure is extended from one of the base and the holding component to face another one of the base and the holding component, so as to limit a position of the holding component relative to the base along a second axial direction.

A optical phase shifter is provided for adjusting an optical phase of light propagating therethrough along an optical axis. The optical phase shifter includes first and second transparent slides defining a cavity therebetween. A sheet is received in the cavity and has first and second sides. The sheet includes a rigid inner portion alignable with the optical axis and is moveable along the optical axis between a first position and a second position. A tuning structure is operatively engageable with the rigid inner portion of the sheet to selectively move the rigid inner portion of the sheet along the optical axis so as to adjust the optical phase of light propagating through the optical phase shifter.

A holographic display includes an illuminator, a spatial light modulator (SLM) coupled to the illuminator, a beam redirector and an ocular lens coupled to the SLM. A controller is operably coupled to the SLM and the beam redirector and configured to provide exit pupils at eyebox locations where a holographic image may be observed. The exit pupils provided in a time-sequential manner, forming a grid of exit pupils/eyebox locations. An eye tracking system may be used to center the grid around the current eye pupil position, to provide a larger overall eyebox for viewing the holographically generated image.

A holographic display includes an illuminator, a spatial light modulator (SLM) coupled to the illuminator, and an ocular lens coupled to the SLM. The SLM includes sequentially coupled first and second pixelated SLM panels for spatially modulating the illuminating light beam in amplitude and phase. At least one of the SLM panels may include a liquid crystal (LC) panel, such as an in-plane switching (IPS) panel. At least one of the SLM panels may include an array of piston-type micromirrors.

A holographic display includes an illuminator, a spatial light modulator (SLM) coupled to the illuminator, and an ocular lens coupled to the SLM. The illuminator provides a wide-area illuminating light beam to illuminate the SLM with a spatially homogeneous beam of light. The illuminator may include a slab waveguide with an evanescent out-coupler, or a beam expander based on a diffraction grating with an oblique angle of incidence and a near-normal angle of diffraction of the illuminating light. A low-pass spatial filter may be provided to filter out higher diffraction orders of the illuminating light diffracted on the SLM.

The present disclosure provides a diffraction light guide plate, including a light guide unit, an input diffraction optical device configured to receive light from a light source and diffract the received light, an intermediate diffraction optical device configured to receive the diffracted light from the input diffraction optical device and extend the received light one-dimensionally by diffraction, and an output diffraction optical device configured to receive the extended light from the intermediate diffraction optical device and output the received light from the light guide unit by diffraction. The intermediate diffraction optical device and the output diffraction optical device are separately disposed in regions divided horizontally on the light guide unit, and the intermediate diffraction optical device includes a main intermediate diffraction optical device and an auxiliary intermediate diffraction optical device, which are disposed separate apart from each other vertically on the light guide unit.

An example architecture for providing a delay line for optical techniques. The delay line architecture includes a focusing element that has a focal axis disposed parallel to its length. The line of symmetry provided by the focal axis obviates path-length-dependent aberrations caused by the off-axis beam translations. The systems also provide varying geometries of movable mirrors, including a galvanometer mirror and a rotating polygonal mirror. The systems and methods also provide techniques for generating and detecting coherent Raman spectra using a picosecond probe pulse.