Abstract: The present disclosure is directed to inventive methods and apparatus for lighting control and for providing effects upon activation/deactivation. For example, various methods and apparatus are described for controlling various selected properties of light emitted by an LED-based lighting unit (100) with multiple LEDs (102) using, for example, a dimmer switch (101) and/or a predefined sequence of energizing LEDs.

Abstract: A fly-eye lens includes: an incident lens assemblage comprising a plurality of incident lenses that are aligned in a vertical direction, wherein each of the incident lenses has a quadrangular shape, wherein horizontal lens widths of the incident lens are the same, and wherein vertical lens widths of at least some of the incident lens are different from one another; and an emission lens assemblage comprising a plurality of emission lenses that are aligned in the vertical direction so as to be optically opposed to the incident lenses, wherein each of the emission lenses has a quadrangular shape, and wherein horizontal lens widths of the emission lenses lens are the same.

Abstract: A projector includes a light source unit having a first light source emitting first wavelength range light and a luminescent wheel having a first wavelength range light transmission area and a luminescent material area receiving the first wavelength range light and reflecting second different wavelength range light provided circumferentially end to end, a light source control unit controlling the light source unit, a display device receiving light from the light source unit to form image light, a pixel shifting unit shifting a display position of the image light for each of a plurality of sub-frame periods forming one image frame period, and a control unit controlling the light source control unit and the pixel shifting unit, the control unit synchronizing a timing the pixel shifting unit shifts the display position for each sub-frame period with a timing the emitted light from the light source unit is switched over.

Abstract: An illumination system and a projection device using this illumination system are provided. The illumination system is adapted to provide an illumination light beam. The illumination system includes a plurality of light emitting element package structures and a light condensing element. The light emitting element package structures are adapted to provide a plurality of excitation light beams, respectively. The light condensing element is disposed on transmission paths of the excitation light beams. Each of the light emitting element package structures includes a substrate, a plurality of light emitting chips, and a package lens. The light emitting chips are disposed on the substrate. The package lens is disposed on the substrate and covers the light emitting chips. Each of the package lenses includes a plurality of lens units, and the lens units in each of the package lenses are integrally connected to cover the light emitting chips.

Abstract: A projection apparatus including an image device and an illumination system is provided. The image device is configured to convert an illumination beam into an image beam. The illumination system includes an illumination light source, a diffusion device and a light uniform device. The illumination light source provides the illumination beam. The illumination beam is transmitted to the image device through the diffusion device and the light uniform device sequentially. The image beam leaves the projection apparatus and converges at a stop. The stop is located outside the projection apparatus. The image beam on the stop has desirable uniformity of an energy intensity distribution.

Abstract: A projection display device includes a light source part including a first light source part that emits first color light and a second light source part that emits second color light having an emission intensity distribution different from that of the first color light, an image generator that generates an image on a basis of light emitted from the light source part, and a projection lens that projects the light outputted from the image generator onto a projection surface and has a projection optical axis that is shifted from a reference optical axis of the device as a whole. An emission optical axis of the first light source part is shifted to a direction opposite to a direction of the projection optical axis having been shifted.

Abstract: An illumination device includes a light source section, an optical element, and a driver. The light source section includes a laser light source. The optical element includes a periodic structure, and is disposed in an optical path of light emitted from the light source section. The driver vibrates the optical element to cause a vibration direction to be inclined to a periodic direction of the periodic structure of the optical element.

Abstract: Disclosed are a dual-view naked-eye 3D display device and a method for manufacturing the same, and a liquid crystal display device. The dual-view naked-eye 3D display device includes a thin film transistor (TFT) substrate, a diffraction grating provided on the TFT substrate, a liquid crystal layer provided on the diffraction grating, a polarizer provided on the liquid crystal layer, and a light source for emitting light to the TFT substrate. The TFT substrate includes a plurality of pixel units arranged in an array, the diffraction grating in each pixel unit having two grating patterns, and the extending directions of the light-shielding strips of the two grating patterns being at a predetermined angle.

Abstract: A projector including an illumination system, a light valve and a projection lens is provided. The illumination system is configured to provide an illumination beam, and includes a light source and a diffusion element. The light source is configured to provide an exciting beam. The diffusion element is located on a transmission path of the exciting beam, and configured to receive the exciting beam for outputting at least part of the illumination beam. The diffusion element includes at least one first diffusion region and at least one second diffusion region surrounding the first diffusion region. A haze of the first diffusion region is greater than a haze of the second diffusion region. The light valve is located on a transmission path of the illumination beam, and configured to convert the illumination beam into an image beam. The projection lens is located on a transmission path of the image beam.

Abstract: The present invention is to provide a method of precisely comparing and positioning speckle patterns, which calculates light intensities of the speckle patterns, is capable of enhancing positioning accuracy of the speckle patterns, and is applicable to various navigation input devices for various types of notebook computers, multi-function keyboard and TV remote control.

Abstract: A projector and a wavelength conversion device thereof are provided. The wavelength conversion device includes a wavelength conversion element and a diffusion element. The wavelength conversion element includes a first substrate and at least one wavelength conversion layer. The at least one wavelength conversion layer is disposed on the first substrate and surrounding an axle center of the first substrate. The at least one wavelength conversion layer is configured to perform a conversion on a light beam. The diffusion element is connected to the first substrate of the wavelength conversion element and surrounding the axle center of the first substrate. The diffusion element is configured to allow another light beam to pass through.

Abstract: A light source assembly includes a substrate, a fixing base, an adjusting frame, an adjusting plate and a lens plate. The substrate includes a plurality of light-emitting units. The fixing base is fixed onto the substrate and comprising a bottom and at least one wall, wherein a recess is formed at least by the bottom and the at least one wall. The adjusting frame is movably disposed in the recess and having an opening. The adjusting plate is movably disposed in the opening of the adjusting frame. The lens plate is fixed onto the adjusting plate and includes a plurality of lenses, wherein a plurality of first through-holes are formed in the bottom of the fixing base and a plurality of second through-holes are formed in the adjusting plate such that the plurality of light-emitting units are exposed from the adjusting plate.

Abstract: An optical wheel device according to the present invention includes a first wheel on one side of which a luminescent material layer is disposed, a second wheel disposed on the other side of the first wheel, a first opening portion provided on the first wheel or the second wheel to be situated near a center of rotation, a second opening portion provided further radially outwards than the first opening portion, a communication passage formed between the first wheel and the second wheel to establish a communication between the first opening portion and the second opening portion, a motor configured to rotationally drive the first wheel and the second wheel, and a drive control device configured to control driving of the motor.

Abstract: The lamp for a vehicle includes a light source part including a light source, a first lens part including a plurality of micro incidence lenses on which light generated from the light source part is incident, a second lens part including a plurality of micro emitting lenses each corresponding to the micro incidence lenses, and a shield part disposed between the first lens part and the second lens part. The shield part includes a plurality of shields configured to block some of the light incident from the micro incidence lenses on the micro emitting lenses. In particular, a center line of the second lens part is disposed to be spaced apart from a center line of the first lens part in at least one of a side direction or a downward direction.

Abstract: An illumination system includes an excitation light source and a wavelength conversion element. The excitation light source provides an excitation beam. The wavelength conversion element has a wavelength conversion region, a reflective region, and a light transmissive region. The wavelength conversion region and the reflective region form an annular region. The light transmissive region is surrounded by the annular region, wherein the excitation beam passes through the light transmissive region of the wavelength conversion element. The illumination system of the disclosure is small in size and achieves favorable optical efficiency. A projection device including the illumination system is also provided.

Abstract: A system configured to be mounted to a vehicle, the system including a display viewable over a predetermined range of distances and a motion sensor configured to detect speeds of one or more vehicles within the predetermined range of distances of the display. The system may receive, via the motion sensor, the speeds of the one or more vehicles and based at least in part on the speeds of the one or more vehicles relative to a threshold speed may display first image data or second image data.

Abstract: The present invention relates to optical imaging devices and methods for reading optical codes. The image device comprises a sensor, a lens, a plurality of illumination devices, and a plurality of reflective surfaces. The sensor is configured to sense with a predetermined number of lines of pixels, where the predetermined lines of pixels are arranged in a predetermined position. The lens has an imaging path along an optical axis. The plurality of illumination devices are configured to transmit an illumination pattern along the optical axis, and the plurality of reflective surfaces are configured to fold the optical axis.

Abstract: An illumination system includes an excitation light source group, a first dichroic device, a second dichroic device, an actuation element, and a wavelength conversion device. The excitation light source group includes a plurality of excitation light sources. Each excitation light source provides an excitation beam. The first dichroic device configures the excitation beam to pass therethrough. The second dichroic device includes a plurality of dichroic elements which are arranged at intervals and reflect the excitation beam. The actuation element configures the excitation beam to pass through the second dichroic device in a first period through intervals between the dichroic elements, and configures the excitation beam to be reflected by the dichroic element in a second period. The wavelength conversion device converts the excitation beam into a conversion beam. The invention further provides a projection device having this illumination system.

Abstract: The present disclosure describes systems and methods for imaging an iris for biometric recognition. An image sensor may be located a distance L from an iris, to acquire an image of the iris. The image may have a contrast amplitude comprising modulation of a signal level at the image sensor due to features of the iris being acquired, and a standard deviation of said signal level due to noise generated within the image sensor. An illumination source may provide infrared illumination during acquisition of the image. When L is set at a value of at least 30 centimeters, the illumination source can provide the infrared illumination to the iris at a first irradiance value, quantified in watts per centimeter-squared, such that the contrast amplitude is at a value above that of the standard deviation, and enables the acquired image to be used for biometric recognition.

Abstract: An illumination system includes a plurality of light source modules and at least one condenser lens. Each of the light source modules includes a first color light source and a wavelength conversion element. The first color light source is configured to provide a first color beam as an excitation beam. The wavelength conversion element is disposed on a transmission path of the first color beam and configured to convert the first color beam into a converted beam. The at least one condenser lens is disposed on transmission paths of the plurality of converted beams from the plurality of wavelength conversion elements and the plurality of first color beams. A projection apparatus including the illumination system is also provided.

Abstract: A beam deflection device includes two arrays of prisms. The prisms in the first array of prisms have an apex angle below a critical angle such that light passes through the prism and is deflected at an angle below a specified angle. The prisms in the second array of prisms have an apex angle above the critical angle such that light that enters the prism will reflect off the apex surface to an exit surface, resulting in the light being deflected at an angle above the specified angle. In some embodiments, the prisms in the first array and the second array work in conjunction to direct light from multiple locations to a single focal point.

Abstract: A light source device including a light emitting device that emits a first light and a second light; a first light separation element that separates the first light into a first light beam flux and a second light beam flux; a second light separation element that separates the second light into a third light beam flux and a fourth light beam flux; at least one fluorescent body layer that includes a first fluorescence emitting section on which the first light beam flux is incident and a second fluorescence emitting section on which the third light beam flux is incident; and at least one diffusion section that includes a first diffusion light emitting section on which the second light beam flux is incident and a second diffusion light emitting section on which the fourth light beam flux is incident.

Abstract: An optical arrangement, comprises first and second optical elements. The first optical plate is for collimating light from a light source to generate collimated light, which is provided to the second optical element. The second optical element acts an optical integrator homogenizing the light. The second optical element further generates a light output beam which has a spread of output angles which is dependent on the position. This means that the output spread of output angles can be controlled by controlling the light reaching the second optical plate and thus by controlling the illuminated area on the second optical plate. This can be achieved by selection of the relative positions of the source and the optical plates.

Abstract: The present disclosure provides a light beam adjusting device, an optical assembly and a lighting and/or signaling apparatus. The light beam adjusting device includes: a light collimating portion arranged to collimate a light beam; and a multi-focal converging portion arranged to converge the collimated light beam, the multi-focal converging portion including two or more converging surfaces, wherein at least two of the two or more converging surfaces have focal points separated spatially from each other.

Abstract: A measurement system includes a projection section that switches first pattern light having a fringe pattern to second pattern light having a fringe pattern containing a greater number of fringes than the first pattern light and vice versa and projects the selected light on an object to be measured, an imaging section that has a plurality of pixels and images the first pattern light and the second pattern light projected on the object to be measured, a phase shift section that shifts the phase of the first pattern light and the second pattern light projected by the projection section on the object to be measured, and an analysis section that analyzes results of the imaging performed by the imaging section by relating the fringes contained in the first pattern light and the second pattern light to the plurality of pixels.

Abstract: System of, and method for, trans-illumination imaging with use of interference fringes to enhance contrast and/or find focus. In an exemplary method, a coherence of light may be reduced upstream of a sample by scattering and mixing at least a portion of the light. The sample may be irradiated with the light of reduced coherence. An image of the sample may be detected, with the image being created with at least a portion of the light of reduced coherence that has passed through a plane defined by the sample. Image detection may be performed with the sample sufficiently defocused to form interference fringes in the image. The step of reducing a coherence of light may attenuate the interference fringes.

Abstract: The purpose of the present invention is to provide a projection type image display apparatus which is simple in configuration, low in price, and improved in reliability and brightness of an illumination light source. The present invention is a projection type image display apparatus provided with: a lamp; a reflector that reflects a light flux emitted from the lamp; a collimating lens that collimates the light reflected by the reflector; a light modulation device that modulates the collimated light to output the modulated light; and a projection lens that projects the modulated light. The reflector is configured to prevent the lamp from being irradiated with the reflected light of the light flux emitted from the lamp, and the collimating lens is formed of one biconcave lens having concave surfaces on both the incident side and the exit side.

Abstract: A method for controlling a robot cleaner configured to project light of a predetermined pattern to a floor of an area in front thereof in a specific direction and to acquire an image of the area to which the light is projected, according to the present disclosure, includes: (a) acquiring a front view image of the robot cleaner; (b) detecting the pattern from the image acquired in (a); and (c) discriminating a pattern formed by reflected light from a pattern formed by light directly projected from the robot cleaner, from among patterns indicated in the acquired image, on the basis of geometrical characteristics defined by a projection direction of the light and the direction of an optical axis in which the image is acquired when two or more patterns are detected from the image.

Abstract: Within a lens-tube main body, the light-shielding member is fixed to a second lens frame in a second portion opposite to a first portion in which an image forming panel is shifted from an optical axis with the optical axis positioned therebetween. Since the light-shielding member is fixed to the second lens frame in the second portion, heat caused by the unnecessary light is distributed from the first portion to the second portion within the light-shielding member. Accordingly, a local temperature rise is suppressed, and deformation of a lens-tube main body is suppressed. Accordingly, tilt of lenses due to deformation of the lenses does not occur, and deterioration in resolution of the entire image caused by the tilt of the lenses or the occurrence of focus position shift in a diagonal direction due to the occurrence of field curvature is suppressed.

Abstract: The present invention provides a projection system (10), preferably for a head-up display e.g. on board a vehicle, comprising a laser source (1), a diffuser (3) and telecentric optics (2) disposed between the laser and the diffuser so that the telecentric optics outputs parallel rays to the diffuser, the diffused light being thus independent from the incidence angle; each pixel of the projected image has the same brightness, regardless of the angle or of the position from which it is viewed.

Abstract: According to one embodiment, an optical device includes a first light-modulating element transmitting or scattering light, and a second light-modulating element transmitting or scattering the light passing through the first light-modulating element, a driving module alternately performing a first mode of making the first light-modulating element scatter the light and making the second light-modulating element transmit the light, and a second mode of making the first light-modulating element transmit the light and making the second light-modulating element scatter the light.

Abstract: An illumination unit including one or more light sources each including a solid-state light-emitting device; and an optical member configured to allow light incident from the solid-state light-emitting device to pass therethrough and exit therefrom, and at least one of the chips in the one or more light sources is configured of a laser diode. The optical member includes an integrator including a first fly-eye lens on which light from the solid-state light-emitting device is incident. A major-axis direction of a luminance distribution shape of light incident on an incident plane of the first fly-eye lens is different from arrangement directions of the cells in the first fly-eye lens.

Abstract: The present disclosure relates to imaging techniques, and more particularly, to a display device configured to generate and display a 2D or 3D image having an increased image size in vertical and/or horizontal directions, an increased image viewing angle and improved image resolution. The technical result of the present disclosure is to increase the size of a displayed image in at least one direction, while simultaneously providing an increased image viewing angle and improved image resolution in the at least one direction. The display device includes an controller, an display, a spatial-to-angular distribution transformer, an image relay and scanner, and a screen.

Abstract: The disclosure provides a fluorescent wheel, including a fluorescent region and a transmission region; the fluorescent region has fluorescence powder for emitting fluorescence under excitation by excitation laser; and the transmission region is for transmitting laser; the fluorescent wheel is for diffusing at least laser to be transmitted. Using fluorescent wheel to diffuse laser enables laser transmission meanwhile removing speckles by diffusion, sparing a separate speckle-removing component, improving light processing efficiency of fluorescent wheel.

Abstract: An iPhone LED projector device that projects a large image from an iPhone onto a nearby wall or screen, where the LED projector is built into a housing for the iPhone, where the iPhone is attached via a lightning connector, where the LED projector device is about the same size as an iPhone and encloses the iPhone in a case, where the LED projector has a removable rechargeable lithium ion battery, an A/C power unit, wherein the LED projector includes external controls on one or more outer surfaces of the housing, wherien the LED projector is able to project an image approximately 100? in size diagonal dimension, and wherein the LED projector includes an audio Bluetooth connection for connecting to an external audio unit.

Abstract: A magnification device includes a two-dimensional array of lens assemblies. The two-dimensional array of lens assemblies includes a first group of multiple lens assemblies of a first magnification and a second group of multiple lens assemblies of a second magnification that is distinct from the first magnification. The first group of multiple lens assemblies of the first magnification includes a first lens assembly and a second lens assembly. The second group of multiple lens assemblies of the second magnification includes a third lens assembly and a fourth lens assembly. Each of the first lens assembly, the second lens assembly, the third lens assembly, and the fourth lens assembly includes two or more lenses. The device also includes a spatial light modulator configured to selectively reduce transmission of light for the two-dimensional array of lens assemblies.

Abstract: A beam conditioning device includes a coherence-breaking module and a beam transforming module. The coherence-breaking module is configured to break a spatial coherence between beam components of the light beam and may include coherence-breaking mirrors having a structured pattern on their reflective surfaces. The beam transforming module may include a primary optical element and a secondary optical element and is configured to transform the spatial energy distribution and the footprint of the light beam. The beam conditioning device may be used to transform a Gaussian light beam into a flat-top light beam suitable for terahertz imaging applications, although other initial and/or final energy distributions may be considered.

Abstract: The present invention relates to optical imaging devices and methods for reading optical codes. The image device comprises a sensor, a lens, a plurality of illumination devices, and a plurality of reflective surfaces. The sensor is configured to sense with a predetermined number of lines of pixels, where the predetermined lines of pixels are arranged in a predetermined position. The lens has an imaging path along an optical axis. The plurality of illumination devices are configured to transmit an illumination pattern along the optical axis, and the plurality of reflective surfaces are configured to fold the optical axis.

Abstract: A lighting device comprising a phosphor arrangement (2) having a phosphor region (31-33), a first laser (5) for irradiating a part of the phosphor region (31-33) with a first laser radiation. The phosphor region (31-33) has at least one phosphor which can be irradiated by the first laser radiation and re-emits the first laser radiation at least partly in a manner wavelength-converted into colored light having a first light color. A second laser (6) is configured for emitting a second laser radiation having a second light color. The second light color of the second laser radiation is identical in color to the first light color of the wavelength-converted colored light. The lighting device is configured to simultaneously emit the second laser radiation and the wavelength-converted colored light of identical color emitted by the phosphor.

Abstract: The disclosure discloses a light source assembly and a laser projector. An embodiment of the disclosure provides a light source assembly including a laser light emitter in at least one color, and a light guiding element arranged in a light path over which a light beam of the laser light emitter is transmitted; the light guiding element is configured to be moved to change the emergent angle of laser light beam being transmitted, thus adjusting the light path conveniently.

Abstract: This disclosure provides a laser speckle-removing optical component, including a beam-shrinking lens group and a diffusion sheet arranged on a laser emergent optical path, where the beam-shrinking lens group includes a first beam-shrinking lens and a second beam-shrinking lens, and the diffusion sheet is located between the first beam-shrinking lens and the second beam-shrinking lens. The arrangement of the diffusion sheet between the first beam-shrinking lens and the second beam-shrinking lens, increases the area of speckles received by the diffusion sheet component, reduces energy density of the light received, and is able to alleviate the accumulation phenomenon of dust particles on the diffusion sheet, therefore, alleviating light attenuation phenomenon, and prolonging the service life of the laser source. This disclosure also provides a double-color laser source, a three-color laser source and a laser projection equipment applying the above laser speckle-removing optical component.

Abstract: A projection image display device includes: laser diodes which emit excitation light; a top-hat diffusing element which diffuses and provides the excitation light with a top-hat intensity distribution; a phosphor which emits light when illuminated by the excitation light diffused by the top-hat diffusing element; an integrator rod which homogenizes the light emitted by the phosphor; DMDs which modulate the light homogenized by the integrator rod; and a projector which projects the light modulated by the DMDs.

Abstract: The invention relates to a photolithographic illuminator device including: a light beam source, a condenser (5), an optical homogenizing system (4) including at least one microlens array, said system being arranged upstream from the condenser, and a shutter (3) arranged at the object focal point of the optical homogenizing system, the illuminator being characterized in that same further comprises a network of aperture diaphragms (8) arranged in the Fourier transform plane of the shutter plane (3). The invention likewise relates to a photolithographic device including such an illuminator.

Abstract: A light source optical system includes a micro lens array, a condenser lens unit, and a dichroic surface. In a direction orthogonal to an optical axis in a cross section parallel to a normal of the dichroic surface and the optical axis of the condenser lens unit, a width of the dichroic surface is narrower than a width of the condenser lens unit. A light source optical system satisfies a predetermined conditional expression.

Abstract: Disclosed is an apparatus and method of tiling and stitching together multi-projector images. The projection system enhances brightness, enables polarization based stereoscopic imagery and matches brightness for all viewers that view the images from the projection system. The projection system includes two or more projectors and projects two dimension and three dimensional images onto projection screens, such as gain screens.

Abstract: The invention relates to a photolithographic illumination device including: a light beam source; a condenser (5); an optical homogenizing system (4), including at least one microlens array (L3, L4), arranged upstream from the condenser (5) such that the image focal plane of the optical homogenizing system is positioned in the object focal plane of the condenser; a shutter (3), arranged in the object focal plane of the optical homogenizing system, and in which the optical homogenizing system includes two microlens arrays (L3, L4), the spacing as well as the arrangement and orientation of the microlenses of which are designed such that, in two directions (X, Y) orthogonal to the optical axis, the optical homogenizing system has merged image focal planes and merged object focal planes. The invention likewise relates to a photolithographic device including such an illuminator.

Abstract: A light source apparatus according to the present disclosure includes: a first light source unit which emits a blue light in a first direction; a second light source unit which emits a blue light in a second direction which intersects with the first direction; a split/combining optical element which splits the blue lights emitted from the first light source unit and the second light source unit, into a first optical path and a second optical path; a light emitting body which is provided on the first optical path and emits an emission light in response to an excitation light; and a combining optical element which combines the first optical path and the second optical path into one optical path.

Abstract: A vehicle lighting fixture can include a plurality of light sources; a plurality of optical deflectors provided to correspond to the light sources, the optical deflector configured to include a mirror part; a screen member configured to form a luminance distribution assigned to each optical deflector with the scanning light by the mirror part of the optical deflector; an optical system configured to project the luminance distributions on the screen member to thereby form a predetermined light distribution pattern; a changing unit configured to change the luminance distribution assigned to each of the optical deflectors; and a control unit configured to control the light sources and the optical deflectors so that the optical deflectors each can form the respective luminance distributions assigned to the respective optical deflectors on the screen member. The changing unit can change the respective luminance distributions assigned to the respective optical deflectors at a prescribed timing.

Abstract: An illumination device includes: a light-emitting element that emits light in a first wavelength band; a substrate rotatable about a predetermined axis of rotation; a phosphor layer that is provided on the substrate at a first distance from the axis of rotation and excited by the light in the first wavelength band to emit light in a second wavelength band different from the first wavelength band; a scattering layer that is provided on the substrate at a second distance, different from the first distance, from the axis of rotation and on which the light in the first wavelength band emitted from the light-emitting element is incident; a first pickup optical system that is provided on the side of the phosphor layer opposite to the substrate; and a second pickup optical system that is provided on the side of the scattering layer opposite to the substrate.

Abstract: A laser device includes: a substrate formed from material transparent at a laser wavelength; a first reflecting layer to reflect at least some incident radiation at the laser wavelength; a layer including a gain medium for providing stimulated emission of radiation at the laser wavelength, and positioned between the first reflecting layer and the substrate; a second reflecting layer on an opposite side of the substrate from the first reflecting layer to reflect at least some incident radiation at the laser wavelength; a spatial light modulator in an optical cavity comprising the first and second reflecting layers, and comprising an array of elements each corresponding to a different path for radiation in the optical cavity; and a computer controller that, during operation, causes the spatial light modulator to selectively vary an intensity or phase of radiation in the optical cavity to provide variable transverse spatial mode output of the radiation.