An optical reflective device referred to as a skew mirror, having a reflective axis that need not be constrained to surface normal, is described. Examples of skew mirrors are configured to reflect light about a constant reflective axis across a relatively wide range of wavelengths. In some examples, a skew mirror has a constant reflective axis across a relatively wide range of angles of incidence. Exemplary methods for making and using skew minors are also disclosed. Skew mirrors include a grating structure, which in some examples comprises a hologram.

A volumetric display system including a volumetric display for displaying a scene viewable as a three-dimensional floating-in-the-air scene in a display space, enabling a user to reach a first object into the display space, a location determination unit locating real objects in the display space, providing a location of the first object when the first object is inserted into the display space, and a computer for receiving the location of the first object, detecting when the location of the first object is at a location where an object is displayed in the three-dimensional scene, thereby determining that the first object is viewable as touching the displayed object following a detection of the first object viewable as touching the displayed object, producing a new three-dimensional scene displaying the displayed object as if manipulated by the first object. Related apparatus and methods are also described.

A lightguide structure for illumination, detection and/or holographic representation includes at least one planar lightguide for guiding electromagnetic radiation of at least a first spectrum, at least one illumination arrangement located on the first side face of the lightguide, and at least one holographic outcoupling structure for coupling out electromagnetic radiation guided in the lightguide structure. The light radiated in by the illumination arrangement can have a large angular range, the holographic outcoupling structure having a small angular range. Also provided is a production method for such a lightguide structure and to an operating element comprising a lightguide structure.

The invention relates to an optical system (1) comprising at least the following components: a first holography arrangement (2) comprising a first diffraction element (3) which is formed by a first prism arrangement (4) having at least a quadrangular base surface, wherein a lateral surface of the first prism arrangement (4) has the following lateral surface regions: a first entrance surface (31) for reference light (100) extending along a first entrance plane (310), a second entrance surface (32) for object light (200) extending along a second entrance plane (320), wherein the first and second entrance surfaces (31, 32) form opposite lateral surface regions of the first prism arrangement (4), an exit surface (33) which extends along an exit plane (330) and through which diffracted reference light (102) and diffracted object light (201) can exit from the first diffraction element (3), a prism surface (34), opposite to the exit surface (33), extending along a prism plane (340), an optical transmission diffraction grating arrangement (36) which is arranged in the first diffraction element (3) and extends along a diffraction plane (360), which intersects the first entrance plane (310), between the first entrance surface (31) and the exit surface (33), wherein the transmission diffraction grating arrangement (36) of the first diffraction element (3) comprises at least one first volume phase hologram grating, and in that the first holography arrangement (2) has, on the side of the prism surface (34), a first mirror (35) having a first mirror plane (350), wherein the first mirror plane (350) encloses an angle with the diffraction plane (360) and the prism plane (340) encloses an angle .sub.2 with the diffraction plane (360), wherein at least one of the angles , .sub.2 is different from 45.

A sensor module is disclosed for a metrology apparatus. The sensor module comprises an illumination device for illuminating a structure on a substrate, said illumination device comprising at least a first set of illuminators and a second set of illuminators, wherein said first set of illuminators comprise one or more illuminators which are each operable to illuminate said structure with first illumination comprising a first optical characteristic and wherein said second set of illuminators comprise one or more illuminators which are each operable to illuminate said structure with second illumination comprising a second optical characteristic different to said first optical characteristic; an optical system being operable to capture scattered radiation scattered by the structure resultant from the structure being illuminated; and a detector operable to detect the scattered radiation.

Disclosed are optical interrogation apparatus that can produce lens-free images using an optoelectronic sensor array to generate a holographic image of sample objects, such as microorganisms in a sample. Also disclosed are methods of detecting and/or identifying microorganisms in a biological sample, such as microorganisms present in low levels. Also disclosed are methods of using systems to detect microorganisms in a biological sample, such as microorganisms present in low levels. In addition or as an alternative, the methods of using systems may identify microorganisms present in a sample and/or determine antimicrobial susceptibility of such microorganisms.

Systems and methods for generating multiple mutually variant wavelengths of coherent radiation for three-dimensional imaging of a physical object, such as a tooth, are disclosed. A single radiation source, such as a laser diode, emits coherent electromagnetic radiation. A highly dispersive optical element, such as an echelle diffraction grating, separates radiation having specific wavelengths from the emitted spectrum into distinct beams. Optical components, such as optical masks, mirrors, and lenses, select and orient desired beams to illuminate the object. Small changes in drive current or heatsink temperature of the radiation source similarly affect all wavelengths of the emitted spectrum, so the relative wavelength differences of the desired beams of radiation remain constant. This wavelength stability is useful for synthetic wavelength generation for digital holography and minimizes errors in object shape profile measurements at various scales. Use of a single radiation source also reduces system cost and complexity.