Abstract: A projection video display includes at least one laser for delivering a light beam. The display includes a beam homogenizer and a condenser lens. A scanning arrangement is provided for scanning the light in beam in a particular pattern over the condenser lens in a manner that effectively increases the beam divergence. The scanned beam is homogenized by a beam homogenizer and a spatial light modulator is arranged to receive the homogenized scanned light beam and spatially modulate the beam in accordance with a component of an image to be displayed. Projection optics are projecting the homogenized scanned light beam onto a screen. The scanning provides that the homogenized scanned light beam at the screen has a coherence radius less than the original coherence radius of the beam. The reduced coherence radius contributes to minimizing speckle contrast in the image displayed on the screen.

Abstract: A projection display including a one-dimensional light modulator includes an optical arrangement for projecting light from a laser onto the modulator in the form of a line of light. Light from the laser is divided to create in effect a two-dimensional array of mutually incoherent light sources. Light from one axis of the array is projected onto the modulator to form the length of the line of light and light from the other axis of the array is projected onto the modulator to form the width of the line of light. Division of the light is accomplished without the use of any moving component.

Abstract: An optical pulse extender includes a delay loop formed by a plurality of mirrors and a graded reflectivity beamsplitter. The mirrors and the beamsplitter are configured and aligned such that a pulse to be broadened makes a predetermined number of round trips in the delay loop and is incident on a different zone of the beamsplitter after each round trip. The different zones of the beamsplitter have different reflection values and different transmission values. These values are selected such that the pulse extender delivers a plurality of temporally and spatially separated replica pulses each thereof having about the same energy. The delivered replica pulses together provide an extended pulse having a longer duration than the input pulse. The replica pulses may be passed through a beam homogenizer to spatially homogenize the temporal characteristics of the extended pulse.

Abstract: External-cavity optically-pumped semiconductor lasers (OPS-lasers) including an OPS-structure having a mirror-structure surmounted by a surface-emitting, semiconductor multilayer (periodic) gain-structure are disclosed. The gain-structure is pumped by light from diode-lasers. The OPS-lasers can provide fundamental laser output-power of about two Watts (2.0 W) or greater. Intracavity frequency-converted arrangements of the OPS-lasers can provide harmonic laser output-power of about one-hundred milliwatts (100 mW) or greater, even at wavelengths in the ultraviolet region of the electromagnetic spectrum. These high output powers can be provided even in single axial-mode operation.

Abstract: In an optically pumped semiconductor laser including a semiconductor laser heterostructure, energy of high-energy electrons of an electron beam is converted by excimer formation and dissociation in a gas into ultraviolet (UV) radiation. The ultraviolet radiation is used to optically pump the heterostructure. Materials of the heterostructure may include II-VI compounds, oxides, or diamond. Both surface-emitting and edge-emitting heterostructures may be optically pumped by the UV radiation.

Abstract: A semiconductor laser includes a multilayer semiconductor laser heterostructure including at least one active layer of a II-VI semiconductor material and is optically pumped by one or more indium gallium nitride (InGaN) diode-lasers. Group II elements in the II-VI semiconductor material are zinc, cadmium, magnesium, beryllium, strontium, and barium. Group VI elements in the II-VI semiconductor material are Sulfur, Selenium, and Tellurium. In one example of the laser an edge emitting heterostructure includes two active layers of zinc cadmium selenide, two waveguide layers of zinc magnesium sulfoselenide, and two cladding layers, also of zinc magnesium sulfoselenide. Proportions of elements in the cladding layer material and the waveguide layer material are selected such that the waveguide layer material has a higher bandgap than the material of the waveguide layers.

Abstract: A traveling-wave ring laser resonator includes one or more gain-elements for generating fundamental radiation and three optically nonlinear crystals. A portion of the fundamental radiation is converted to second-harmonic radiation in a first of the crystals. Remaining fundamental radiation and the second-harmonic radiation traverse a second of the optically nonlinear crystals where a portion of each is converted to third-harmonic radiation. Fundamental and second-harmonic radiation pass through the third of the optically nonlinear crystals where most of the second-harmonic radiation is converted back to fundamental radiation. The third-harmonic radiation can be delivered from the resonator as output radiation or mixed with the fundamental radiation in a fourth optically nonlinear crystal to generate fourth harmonic radiation. An optical parametric oscillator arrangement is also disclosed.

Abstract: Laser apparatus including two different, pulsed MOPAs, one having a fundamental wavelength of 1064 nm and the other having a fundamental wavelength of 1564 nm, provide trains of optical pulses. The 1064-nm pulses are frequency tripled to 355 nm and the 1564-nm pulses are frequency doubled to 782 nm. The 355-nm and 782-nm pulses are mixed to provide 244-nm pulses. The 244-nm pulses are mixed with residual 1064-nm pulses to provide 198-nm output pulses of the apparatus. The output pulses can be either digitally modulated or amplitude modulated by controlling the phase relationship between the 1064-nm and 1564-nm pulses.

Abstract: A combined radiation pulse of a predetermined energy is provided by temporally and spatially overlapping four pulses from four extra-cavity, frequency-tripled lasers. Frequency tripling is effected in each laser by a second-harmonic generating crystal followed by a third-harmonic generating crystal. One of the lasers includes a Pockels cell preceding the second-harmonic generating crystal. The third harmonic pulse from this laser is the fourth and last delivered in the sequence. The total available energy in three of the pulses is less than the predetermined energy. The cumulative integrated energy of the pulses is determined while the pulses are being delivered. When the energy is determined to have reached the predetermined value, the Pockels cell is activated to rotate the polarization plane of fundamental radiation entering the second-harmonic generating crystal, thereby terminating generation of the fourth pulse and delivering the combined radiation pulse at the predetermined energy.

Abstract: An optical pulse extender includes a delay loop formed by a plurality of mirrors and a graded reflectivity beamsplitter. The mirrors and the beamsplitter are configured and aligned such that a pulse to be broadened makes a predetermined number of round trips in the delay loop and is incident on a different zone of the beamsplitter after each round trip. The different zones of the beamsplitter have different reflection values and different transmission values. These values are selected such that the pulse extender delivers a plurality of temporally and spatially separated replica pulses each thereof having about the same energy. The delivered replica pulses together provide an extended pulse having a longer duration than the input pulse. The replica pulses may be passed through a beam homogenizer to spatially homogenize the temporal characteristics of the extended pulse.

Abstract: A projection video display includes at least one laser for delivering a light beam. The display includes a beam homogenizer and a condenser lens. A scanning arrangement is provided for scanning the light in beam in a particular pattern over the condenser lens in a manner that effectively increases the beam divergence. The scanned beam is homogenized by a beam homogenizer and a spatial light modulator is arranged to receive the homogenized scanned light beam and spatially modulate the beam in accordance with a component of an image to be displayed. Projection optics are projecting the homogenized scanned light beam onto a screen. The scanning provides that the homogenized scanned light beam at the screen has a coherence radius less than the original coherence radius of the beam. The reduced coherence radius contributes to minimizing speckle contrast in the image displayed on the screen.

Abstract: A projection video display includes a light source including an OPS-laser delivering laser radiation in multiple transverse modes (a multiple-transverse-mode OPS-laser). The display includes a spatial light modulator for spatially modulating the radiation from the multiple-transverse-mode OPS-laser in accordance with a portion of an image to be displayed. Projection optics project the spatially modulated light on a screen on which the image is to be displayed. In one example the OPS-laser is a diode-laser array pumped OPS-laser and is one of three lasers, one delivering red light, one delivering blue light, and the other delivering green light. The lasers are time modulated such that the spatial light modulator receives light from each of the lasers separately. The OPS laser is directly time modulated by periodically turning the diode-laser array on and off.

Abstract: An optical pulse extender includes a delay loop formed by a plurality of mirrors and a graded reflectivity beamsplitter. The mirrors and the beamsplitter are configured and aligned such that a pulse to be broadened makes a predetermined number of round trips in the delay loop and is incident on a different zone of the beamsplitter after each round trip. The different zones of the beamsplitter have different reflection values and different transmission values. These values are selected such that the pulse extender delivers a plurality of temporally and spatially separated replica pulses each thereof having about the same energy. The delivered replica pulses together provide an extended pulse having a longer duration than the input pulse. The replica pulses may be passed through a beam homogenizer to spatially homogenize the temporal characteristics of the extended pulse.

Abstract: An optically pumped semiconductor laser in accordance with the present invention includes a II-VI semiconductor laser chip A plurality of InGaN LEDs provides optical pump light for optically pumping the laser chip. An optical arrangement collects the pump light from the LEDs and directs the pump light to light-concentrating optical device that is either directly or indirectly in optical contact with the laser chip and is arranged to concentrate the pump light on the chip with maximized numerical aperture (NA). In one example of the laser, the light-concentrating device is an immersion lens. In another example of the laser, the light-concentrating device is a tapered light-pipe.

Abstract: A semiconductor laser includes a multilayer semiconductor laser heterostructure including at least one active layer of a II-VI semiconductor material and is optically pumped by one or more indium gallium nitride (InGaN) diode-lasers. Group II elements in the II-VI semiconductor material are zinc, cadmium, magnesium, beryllium, strontium, and barium. Group VI elements in the II-VI semiconductor material are Sulfur, Selenium, and Tellurium. In one example of the laser an edge emitting heterostructure includes two active layers of zinc cadmium selenide, two waveguide layers of zinc magnesium sulfoselenide, and two cladding layers, also of zinc magnesium sulfoselenide. Proportions of elements in the cladding layer material and the waveguide layer material are selected such that the waveguide layer material has a higher bandgap than the material of the waveguide layers.

Abstract: External-cavity optically-pumped semiconductor lasers (OPS-lasers) including an OPS-structure having a mirror-structure surmounted by a surface-emitting, semiconductor multilayer (periodic) gain-structure are disclosed. The gain-structure is pumped by light from diode-lasers. The OPS-lasers can provide fundamental laser output-power of about two Watts (2.0 W) or greater. Intracavity frequency-converted arrangements of the OPS-lasers can provide harmonic laser output-power of about one-hundred milliwatts (100 mW) or greater, even at wavelengths in the ultraviolet region of the electromagnetic spectrum. These high output powers can be provided even in single axial-mode operation.

Abstract: An optical pulse extender includes a delay loop formed by a plurality of mirrors and a graded reflectivity beamsplitter. The mirrors and the beamsplitter are configured and aligned such that a pulse to be broadened makes a predetermined number of round trips in the delay loop and is incident on a different zone of the beamsplitter after each round trip. The different zones of the beamsplitter have different reflection values and different transmission values. These values are selected such that the pulse extender delivers a plurality of temporally and spatially separated replica pulses each thereof having about the same energy. The delivered replica pulses together provide an extended pulse having a longer duration than the input pulse. The replica pulses may be passed through a beam homogenizer to spatially homogenize the temporal characteristics of the extended pulse.

Abstract: A traveling-wave ring laser resonator includes one or more gain-elements for generating fundamental radiation and three optically nonlinear crystals. A portion of the fundamental radiation is converted to second-harmonic radiation in a first of the crystals. Remaining fundamental radiation and the second-harmonic radiation traverse a second of the optically nonlinear crystals where a portion of each is converted to third-harmonic radiation. Fundamental and second-harmonic radiation pass through the third of the optically nonlinear crystals where most of the second-harmonic radiation is converted back to fundamental radiation. The third-harmonic radiation can be delivered from the resonator as output radiation or mixed with the fundamental radiation in a fourth optically nonlinear crystal to generate fourth harmonic radiation. An optical parametric oscillator arrangement is also disclosed.

Abstract: A method of intracavity frequency conversion in a CW laser includes causing fundamental radiation to circulate in a laser resonator. The fundamental radiation makes a first pass through an optically nonlinear crystal where a fraction of the fundamental radiation generates second-harmonic radiation in a forward pass through the crystal. The residual fundamental radiation and the second-harmonic radiation are then sum-frequency mixed in forward and reverse passes through an optically nonlinear crystal such that a fraction of each is converted to third-harmonic radiation. The residual second-harmonic radiation and fundamental radiation from the sum-frequency mixing then make a reverse pass through the second-harmonic generating crystal where the second-harmonic radiation is converted back to fundamental radiation. The third harmonic radiation can be delivered from the resonator as output radiation, or can be used to pump another optically nonlinear crystal in an optical parametric oscillator.

Abstract: External-cavity optically-pumped semiconductor lasers (OPS-lasers) including an OPS-structure having a mirror-structure surmounted by a surface-emitting, semiconductor multilayer (periodic) gain-structure are disclosed. The gain-structure is pumped by light from diode-lasers. The OPS-lasers can provide fundamental laser output-power of about two Watts (2.0 W) or greater. Intracavity frequency-converted arrangements of the OPS-lasers can provide harmonic laser output-power of about one-hundred milliwatts (100 mW) or greater, even at wavelengths in the ultraviolet region of the electromagnetic spectrum. These high output powers can be provided even in single axial-mode operation.