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: A wavelength-locking arrangement for a diode-laser bar includes a cylindrical fast-axis collimating lens and a fast-axis corner reflector. An optical filter is located between the cylindrical lens and the corner reflector for defining the locked wavelength. The corner reflector provides that radiation emitted by each of the diode-lasers and collimated by the cylindrical lens is reflected back to the cylindrical lens and is focused by the cylindrical lens back into the diode-laser from which the radiation was emitted, independent of the fast-axis alignment of the diode-laser with the cylindrical lens.

Abstract: Arrangements for combination and fast-axis alignment of fast-axes of diode-laser beams are disclosed. Alignment arrangements include providing each diode-laser with a corresponding alignable fast-axis collimating lens, providing individually alignable mirrors for steering an re-orienting beams from each diode-laser, and providing single diode-laser slab-modules in which the diode-laser beams can be pre-aligned to a common propagation-axis direction, and in which edges and surfaces of the slabs can be used to align the fast and slow-axes of the beams. Beam combination methods include combination by dichroic elements, polarization-sensitive elements, and optical fiber bundles.

Abstract: An amorphous silicon layer on a glass substrate is crystallized by concentrating CW radiation from a number of OPS-lasers into a line of light on the layer. The layer is moved with respect to the line of light to control the dwell time of the line on any location on the layer and to crystallize an extended area of the layer.

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: The lifetime of optical components used in deep-UV (DUV) excimer laser systems, including systems in a MOPA configuration, can be increased by reducing the intensity of pulses incident upon these components. In one approach, an output pulse can be “stretched” in order to reduce the peak power of the pulse. A pulse stretching component can be used, which can be mounted outside the laser enclosure with a horizontal beam path in order to provide a delay line with a minimum impact on the laser system footprint. The horizontal beam path also can minimize the number of optical components in the arm containing the high power beam. A beamsplitting prism can be used with the delay line to avoid the rapid degradation of coatings otherwise exposed to intense UV beams. The prism can expand the beam in the delay line in order to minimize beam intensity and losses due to reflection.

Abstract: A Master Oscillator (MO)—Power Amplifier (PA) configuration (MOPA) can be used advantageously in an excimer laser system for micro-lithography applications, where semiconductor manufacturers demand powers of 40 W or more in order to support the throughput requirements of advanced lithography scanner systems. A MOPA-based laser system can provide both high pulse energies and high spectral purity. A MOPA system can utilize a multi-pass PA, as well as a special beam path capable of reducing the amount of ASE (Amplified Spontaneous Emission) and feedback to the MO. Lithography scanner optics are primarily fused silica, such that the peak pulse power must be kept low to avoid material compaction when a MOPA system is used with lithography applications. This conflict between the demand for high average power and the low peak power requirement of the pulsed excimer laser source can be resolved by using a novel beam path to generate a sufficiently long pulse length.

Abstract: The lifetime of optical components used in deep-UV (DUV) excimer laser systems, including systems in a MOPA configuration, can be increased by reducing the intensity of pulses incident upon these components. In one approach, an output pulse can be “stretched” in order to reduce the peak power of the pulse. A pulse stretching component can be used, which can be mounted outside the laser enclosure with a horizontal beam path in order to provide a delay line with a minimum impact on the laser system footprint. The horizontal beam path also can minimize the number of optical components in the arm containing the high power beam. A beamsplitting prism can be used with the delay line to avoid the rapid degradation of coatings otherwise exposed to intense UV beams. The prism can expand the beam in the delay line in order to minimize beam intensity and losses due to reflection.

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: Pulse parameters of a gas discharge laser system can be optimized and controlled for precision applications such as microlithography. Important laser pulse parameters typically vary in the beginning of a pulse burst, and the directionality of the output beam typically varies throughout the burst. In order to improve the performance of the laser system, the variation at the beginning of a pulse burst can be eliminated by extending the pulse pattern and shuttering the output during periods of significant parameter variation. A fast shutter such as an acousto-optical modulator can be used to prevent output during the burst transition processes. Elements such as acousto-optical cells also can be used in combination with a fast position sensor to steer the direction of the output beam, in order to adjust for variations in the direction of the beam between pulses in a burst.

Abstract: A method for measuring amplified spontaneous emission (ASE) content in a beam of laser radiation emitted by a laser master oscillator power-amplifier system comprises directing the beam of light into a two-beam interferometer having unequal beam path lengths. The two beams interfering in the interferometer have equal amplitude and form a pattern of interference fringes. The beam-path difference is arranged to be greater than the coherence length of the ASE so that the ASE content of the beam does not form interference fringes but provides a background level of light in the interference pattern. This enables the ASE content of the beam to be determined from measurements of the maximum intensity of a bright fringe and the minimum energy of a dark fringe in the interference pattern.

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 oil-free pulser design can be used to produce an excimer or molecular fluorine laser system that is lighter, cheaper to produce, and simpler than existing systems. Such designs allow a relatively low DC voltage to be applied to a main transformer, allowing the pulser to be run without oil cooling. This relatively low voltage can be increased to the necessary voltage level, such as on the order to 12 kV to 15 kV, needed to drive the laser system. This transference can be accomplished using standard components, such as a pair of capacitor elements that are pulse-charged in parallel, but can be discharged in series following a reversal of charge on one of the capacitor elements.

Abstract: Precise timing control can be obtained for a gas discharge laser, such as an excimer or molecular fluorine laser, using a timed trigger ionization. Instead of using a standard approach to control the timing of the emission or amplification of an optical pulse using the discharge of the main electrodes, the timing of which can only be controlled to within about 10 ns, a trigger ionization pulse applied subsequent to the charging of the main electrodes can be used to control the timing of the discharge, thereby decreasing the timing variations to about 1 ns. Since ionization of the laser gas can consume relatively small amounts of energy, such a circuit can be based on a fast, high-voltage, solid state switch that is virtually free of jitter. Trigger ionization also can be used to synchronize the timing of dual chambers in a MOPA configuration. In one such approach, ionization trigger can include at least a portion of the optical pulse from the oscillator in a MOPA configuration.

Abstract: A beam parameter monitoring unit for coupling with an excimer or molecular fluorine (F2) laser resonator that produces an output beam having a wavelength below 200 nm includes an on-line laser pulse energy detector. This, in turn, allows output pulse energy stabilization to the same degree of accuracy, which is crucial for stability of exposure dose and other process parameters in microlithography and industrial applications.

Abstract: The relative timing delay between channels of a discharge circuit can be adjusted through application of appropriate control voltages. A control voltage of relatively long duration and relatively small voltage, with respect to a common system pulse, can be applied to any channel in order to adjust the relative timing delay. This control voltage can be, for example, a magnetization pre-pulse voltage applied to an indictor for a channel in order to adjust a hold-off time. A synchronization control unit and feedback loop can be used to monitor the timing, such that the syncronization control unit can apply a control voltage when a delay change exceeds a timing adjustment threshold value, and can apply a pre-ionization voltage when the delay change is less than the adjustment threshold value. Using both a control voltage and a pre-ionization voltage provides for both coarse and fine adjustment of the delay.

Abstract: A method for measuring amplified spontaneous emission (ASE) content in a beam of laser radiation emitted by a laser master oscillator power-amplifier system comprises directing the beam of light into a two-beam interferometer having unequal beam path lengths. The two beams interfering in the interferometer have equal amplitude and form a pattern of interference fringes. The beam-path difference is arranged to be greater than the coherence length of the ASE so that the ASE content of the beam does not form interference fringes but provides a background level of light in the interference pattern. This enables the ASE content of the beam to be determined from measurements of the maximum intensity of a bright fringe and the minimum energy of a dark fringe in the interference pattern.

Abstract: A Master Oscillator (MO)— Power Amplifier (PA) configuration (MOPA) can be used advantageously in an excimer laser system for micro-lithography applications, where semiconductor manufacturers demand powers of 40 W or more in order to support the throughput requirements of advanced lithography scanner systems. A MOPA-based laser system can provide both high pulse energies and high spectral purity. A MOPA system can utilize a multi-pass PA, as well as a special beam path capable of reducing the amount of ASE (Amplified Spontaneous Emission) and feedback to the MO. Lithography scanner optics are primarily fused silica, such that the peak pulse power must be kept low to avoid material compaction when a MOPA system is used with lithography applications. This conflict between the demand for high average power and the low peak power requirement of the pulsed excimer laser source can be resolved by using a novel beam path to generate a sufficiently long pulse length.

Abstract: Precise timing control can be obtained for a gas discharge laser, such as an excimer or molecular fluorine laser, using a timed trigger ionization. Instead of using a standard approach to control the timing of the emission or amplification of an optical pulse using the discharge of the main electrodes, the timing of which can only be controlled to within about 10 ns, a trigger ionization pulse applied subsequent to the charging of the main electrodes can be used to control the timing of the discharge, thereby decreasing the timing variations to about 1 ns. Since ionization of the laser gas can consume relatively small amounts of energy, such a circuit can be based on a fast, high-voltage, solid state switch that is virtually free of jitter. Trigger ionization also can be used to synchronize the timing of dual chambers in a MOPA configuration. In one such approach, ionization trigger can include at least a portion of the optical pulse from the oscillator in a MOPA configuration.

Abstract: Pulse parameters of a gas discharge laser system can be optimized and controlled for precision applications such as microlithography. Important laser pulse parameters typically vary in the beginning of a pulse burst, and the directionality of the output beam typically varies throughout the burst. In order to improve the performance of the laser system, the variation at the beginning of a pulse burst can be eliminated by extending the pulse pattern and shuttering the output during periods of significant parameter variation. A fast shutter such as an acousto-optical modulator can be used to prevent output during the burst transition processes. Elements such as acousto-optical cells also can be used in combination with a fast position sensor to steer the direction of the output beam, in order to adjust for variations in the direction of the beam between pulses in a burst.