Abstract: A layer on a substrate is laser annealed by pulses in a plurality of laser beams formed into a uniform line beam. The laser beams are partitioned into a first set of beams and a second set of beams. The second set of beams is incident onto the layer from a smaller range of angles than all of the beams combined. Pulses in the beams are synchronized such that pulses in the first set of beams are incident on the layer before pulses in the second set of beams. Pulses in the first set of beams melt the layer and pulses in the second set of beams sustain melting.

Abstract: A method for frequency conversion in a single-longitudinal-mode linear resonator includes frequency converting intracavity laser radiation in a nonlinear crystal disposed in a linear resonator. The intracavity laser radiation is in a single longitudinal mode of the resonator and forms a standing wave between its end-mirrors. The method also includes repeatedly sweeping the standing wave back and forth, along an optical axis of the resonator, relative to the nonlinear crystal. This repeated sweeping may be achieved by dithering the longitudinal position of (a) one or both of the end-mirrors or (b) the nonlinear crystal. Dithering of a single end-mirror may be driven by modulating a reference wavelength to which the wavelength of the intracavity laser radiation is locked. Dithering of the longitudinal position of the nonlinear crystal may be achieved with a piezoelectric actuator arranged to adjust angles of a parallelogram-shaped flexure to which the nonlinear crystal is mounted.

Abstract: A system for correcting the wavefront of a laser beam includes a beamsplitter for splitting off a fraction of the laser beam to be used as a diagnostic beam, a focusing element for bringing the diagnostic beam to a focus, a measurement subsystem for measuring sizes of the diagnostic beam at upstream and/or downstream locations with respect to a nominal location of the focus, and at least one adaptive optic, located upstream from the beamsplitter, for correcting the wavefront of the laser beam at least partly based on the measured sizes of the diagnostic beam at the upstream and/or downstream locations. The upstream and downstream locations correspond to mid-field locations in the laser beam as imaged by the focusing element. The system takes advantage of the sensitivity of the laser beam size to a waist location shift being greatest at one Rayleigh length from the nominal waist location.

Abstract: A layer on a substrate is laser annealed by pulses in a plurality of laser beams formed into a uniform line beam. The laser beams are partitioned into a first set of beams and a second set of beams. The second set of beams is incident onto the layer from a smaller range of angles than all of the beams combined. Pulses in the beams are synchronized such that pulses in the first set of beams are incident on the layer before pulses in the second set of beams. Pulses in the first set of beams melt the layer and pulses in the second set of beams sustain melting.

Abstract: An excimer laser includes a chamber for containing a gas mixture between a rear end and a front end of a linear laser resonator, a convex end-mirror defining the rear end, and a plurality of output-coupling mirrors collectively defining the front end. The output-coupling mirrors are distributed along an optical axis of the resonator and have respective normal vectors pointing toward the rear end. The normal vectors include four mutually non-parallel normal vectors, wherein no three of the four mutually non-parallel normal vectors are coplanar. These different orientations of the output-coupling mirrors cooperate with the convex end-mirror to blur fine structure in the output beam of the resonator.

Abstract: A laser apparatus with non-collinearly phase-matched frequency mixing includes a nonlinear crystal generating an output laser beam from non-collinearly phase-matched frequency mixing of first and second input laser beams. The output laser beam is subject to walk-off in a walk-off plane. The second input laser beam is less powerful than the first input laser beam. The first input laser beam is directed to more closely align its Poynting vector to the output beam Poynting vector than in collinear phase matching. To achieve good spatial overlap in this phase matching scheme, the second input laser beam is elongated in the walk-off plane, such that the second input laser beam has a greater transverse size than the first input laser beam in the walk-off plane. This non-collinear phase matching scheme is capable of achieving an improved beam quality of the output beam, as compared to collinear phase matching with circular input beams.

Abstract: A method for inter-substrate transfer of microelectronic devices includes applying a polymer coating to a top surface of a microelectronic device located on a first substrate, depositing an ultraviolet-transmissive adhesive on a second substrate, contacting the polymer-coated top surface of the microelectronic device to the adhesive to bond the microelectronic device to the second substrate, detaching the microelectronic device from the first substrate, and, while the bottom surface of the microelectronic device faces a third substrate, irradiating and ablating the polymer coating with ultraviolet laser light through the second substrate and the adhesive to transfer the microelectronic device from the second substrate to the third substrate via laser lift-off.

Abstract: A method for intracavity frequency conversion includes end-pumping a solid-state gain medium in a laser resonator with a pump laser beam to generate an intracavity laser beam circulating in the laser resonator, and frequency-converting a portion of the intracavity laser beam in a nonlinear crystal, located in the laser resonator, to generate a frequency-converted laser beam. The method controls the output power and at least one output beam parameter of the frequency-converted laser beam by adjusting (a) the pump power and (b) a resonator loss imposed on the intracavity laser beam. Taking advantage of both the pump laser beam and the intracavity laser beam contributing to thermal lensing in the gain medium, this control scheme is capable of controlling the output power and the output beam parameter(s) independently of each other.

Abstract: A device for shifting a nonlinear crystal arranged to frequency convert a laser beam includes an anchor, a mount for holding the nonlinear crystal, and two parallel flexures each interconnecting the mount and the anchor to cantilever the mount from the anchor. Each flexure extends in a first horizontal direction from the mount to the anchor. The two flexures being offset from each other in a vertical direction. The device also includes a transducer connecting between the anchor and the mount. Bending of the transducer shifts the position of the mount in the vertical direction, and the two parallel flexures cooperate to prevent rotation of the mount during shifting of the mount position induced by the transducer. This device provides an inexpensive and compact crystal-shifter solution with crystal-orientation stability equaling that of far more costly and bulky conventional translation stages.

Abstract: A device for shifting a nonlinear crystal arranged to frequency convert a laser beam includes an anchor, a mount for holding the nonlinear crystal, and two parallel flexures each interconnecting the mount and the anchor to cantilever the mount from the anchor. Each flexure extends in a first horizontal direction from the mount to the anchor. The two flexures being offset from each other in a vertical direction. The device also includes a transducer connecting between the anchor and the mount. Bending of the transducer shifts the position of the mount in the vertical direction, and the two parallel flexures cooperate to prevent rotation of the mount during shifting of the mount position induced by the transducer. This device provides an inexpensive and compact crystal-shifter solution with crystal-orientation stability equaling that of far more costly and bulky conventional translation stages.

Abstract: A device for thermally actuating a deformable mirror includes a monolithic block that includes a mirror plate having a front face forming or configured to support a mirror, a base, and a one-dimensional array of thermally expandable actuators. The thermally expandable actuators mechanically connect a rear face of the mirror plate to the base such that shape, tilt, and/or location of the front face depend on temperature of the thermally expandable actuators. The mirror plate, base, and thermally expandable actuators are defined by slits that span between opposite-facing top and bottom surfaces of the monolithic block. The monolithic block may be made of a metal and may be manufactured at relatively low cost by wire eroding the slits in a metal block, using a wire that passes through the metal block between its top and bottom surfaces.

Abstract: A system for resonantly enhanced frequency conversion includes a nonlinear crystal for frequency converting a pump laser beam, and mirrors forming a ring resonator for the pump laser beam such that a closed propagation path of the pump laser beam, inside the ring resonator, passes through the nonlinear crystal. The mirrors include an adaptive mirror, a curved-mirror pair positioned in a first segment of the propagation path spanning between the adaptive mirror and the nonlinear crystal, and an input coupler for coupling the pump laser beam into the ring resonator. The curved-mirror pair forms an imaging system having conjugate planes at the adaptive mirror and the nonlinear crystal. The input coupler is positioned in a second segment of the propagation path that spans between the adaptive mirror and the nonlinear crystal and does not include deflection by the curved-mirror pair.

Abstract: A layer on a substrate is laser annealed by pulses in a plurality of laser beams formed into a uniform line beam. The laser beams are partitioned into a first set of beams and a second set of beams. The second set of beams is incident onto the layer from a smaller range of angles than all of the beams combined. Pulses in the beams are synchronized such that pulses in the first set of beams are incident on the layer before pulses in the second set of beams. Pulses in the first set of beams melt the layer and pulses in the second set of beams sustain melting.

Abstract: A system for resonantly enhanced frequency conversion includes a nonlinear crystal for frequency converting a pump laser beam, and mirrors forming a ring resonator for the pump laser beam such that a closed propagation path of the pump laser beam, inside the ring resonator, passes through the nonlinear crystal. The mirrors include an adaptive mirror, a curved-mirror pair positioned in a first segment of the propagation path spanning between the adaptive mirror and the nonlinear crystal, and an input coupler for coupling the pump laser beam into the ring resonator. The curved-mirror pair forms an imaging system having conjugate planes at the adaptive mirror and the nonlinear crystal. The input coupler is positioned in a second segment of the propagation path that spans between the adaptive mirror and the nonlinear crystal and does not include deflection by the curved-mirror pair.

Abstract: A system for correcting the wavefront of a laser beam includes a beamsplitter for splitting off a fraction of the laser beam to be used as a diagnostic beam, a focusing element for bringing the diagnostic beam to a focus, a measurement subsystem for measuring sizes of the diagnostic beam at upstream and/or downstream locations with respect to a nominal location of the focus, and at least one adaptive optic, located upstream from the beamsplitter, for correcting the wavefront of the laser beam at least partly based on the measured sizes of the diagnostic beam at the upstream and/or downstream locations. The upstream and downstream locations correspond to mid-field locations in the laser beam as imaged by the focusing element. The system takes advantage of the sensitivity of the laser beam size to a waist location shift being greatest at one Rayleigh length from the nominal waist location.

Abstract: A device for thermally actuating a deformable mirror includes a monolithic block that includes a mirror plate having a front face forming or configured to support a mirror, a base, and a one-dimensional array of thermally expandable actuators. The thermally expandable actuators mechanically connect a rear face of the mirror plate to the base such that shape, tilt, and/or location of the front face depend on temperature of the thermally expandable actuators. The mirror plate, base, and thermally expandable actuators are defined by slits that span between opposite-facing top and bottom surfaces of the monolithic block. The monolithic block may be made of a metal and may be manufactured at relatively low cost by wire eroding the slits in a metal block, using a wire that passes through the metal block between its top and bottom surfaces.

Abstract: A beam homogenizer for transforming a beam of laser-radiation into a flat-top intensity distribution having brighter or darker edges comprises a first lens array, a second lens array, and a positive lens. The first lens array includes a plurality of lens elements that are separated by gaps having no optical power. Brighter or darker edges are produced by selecting a distance between the first and second lens arrays that is less than or greater than the focal length of lens elements in the second lens array.

Abstract: Fine-structure in the transverse mode of an excimer laser beam is minimized by having a plurality of resonator mirrors located at each end of a linear excimer laser. At one end, a highly-reflective end mirror and a partially-reflective end mirror are inclined at small angle with respect to each other. At the other end, two output-coupling mirrors are inclined at a small angle with respect to each other. This arrangement of resonator mirrors generates a composite laser beam that blurs any fine structure.

Abstract: An optic produces a beam of ultraviolet laser radiation from a beam of visible laser radiation and spatially separates the ultraviolet laser beam from the visible laser beam. The optic includes two crystals made of the same optically-nonlinear material that are contact bonded along a planar interface. One crystal has principle crystal axes that are oriented for type-I second-harmonic generation. The ultraviolet laser beam exits the optic through an uncoated surface of the other crystal. The principle crystal axes of the two crystals have different orientations and have reflection symmetry about the planar interface.

Abstract: An optic produces a beam of ultraviolet laser radiation from a beam of visible laser radiation and spatially separates the ultraviolet laser beam from the visible laser beam. The optic includes two crystals made of the same optically-nonlinear material that are contact bonded along a planar interface. One crystal has principle crystal axes that are oriented for type-I second-harmonic generation. The ultraviolet laser beam exits the optic through an uncoated surface of the other crystal. The principle crystal axes of the two crystals have different orientations and have reflection symmetry about the planar interface.