Abstract:
A light wavelength meter (10) able to accept light into a light diverter (16) and impart to it a transverse displacement characteristic which can be detected in a light detection unit (20) connected to a processor (22). Optionally, a light diverger (18) may be provided to enhance angular resolution. The light diverter (16) and the light diverger (18) may either transmit or reflect the light. The light diverter (16) may particularly include a diffraction grating (116, 156), Fabry-Perot interferometer (216), multiple slit plate (316), or an acousto-optical unit (416).
Abstract:
A stabilisation system for stabilising an output of a controllable light or laser source comprises a randomizer for randomizing light from the controllable light or laser source to generate a speckle pattern; a detector for detecting the speckle pattern to determine one or more properties of the light and/or changes in one or more properties of the light; and a controller for controlling the controllable light or laser source based on the determined one or more properties of the light and/or changes in one or more properties of the light.
Abstract:
A method and apparatus for producing with a gas discharge laser an output laser beam comprising output laser light pulses, for delivery as a light source to a utilizing tool is disclosed which may comprise a beam path and a beam homogenizer in the beam path. The beam homogenizer may comprise at least one beam image inverter or spatial rotator, which may comprise a spatial coherency cell position shifter. The homogenizer may comprise a delay path which is longer than, but approximately the same delay as the temporal coherence length of the source beam. The homogenizer may comprise a pair of conjoined dove prisms having a partially reflective coating at the conjoined surfaces of each, a right triangle prism comprising a hypotenuse face facing the source beam and fully reflective adjoining side faces or an isosceles triangle prism having a face facing the source beam and fully reflective adjoining side faces or combinations of these, which may serve as a source beam multiple alternating inverted image creating mechanism. The beam path may be part of a bandwidth measuring the bandwidths of an output laser beam comprising output laser light in the range of below 500 femtometers at accuracies within tens of femtometers. The homogenizer may comprise a rotating diffuser which may be a ground glass diffuser which may also be etched. The wavemeter may also comprise a collimator in the beam path collimating the diffused light; a confocal etalon creating an output based upon the collimated light entering the confocal etalon; and a detector detecting the output of the confocal etalon and may also comprise a scanning mechanism scanning the angle of incidence of the collimated light entering the confocal etalon which may scan the collimated light across the confocal etalon or scan the etalon across the collimated light, and may comprise an acousto-optical scanner. The confocal etalon may have a free spectral range approximately equal to the E95 width of the beam being measured. The detector may comprise a photomultiplier detecting an intensity pattern of the output of the confocal etalon.
Abstract:
The present invention relates to an approach to locking the output wavelength of a laser (102) that uses an etalon (112) having non-parallel surfaces (122, 124). Under this approach, the non-parallel etalon (112) is formed from a readily available, low cost optical component, and may include an etalon with a wedged shape or with at least one curved surface. This approach offers significant advantages over the use of a planar etalon. It provides two degrees of freedom in alignment of the device, and so both the absolute wavelength and the spacing between the interference fringes can be independently adjusted. It also reduces the cost and difficulty of assembly, since it utilizes standard optical parts with wide tolerances. The invention may be used within a standard laser package. The invention also permits the laser to be tuned to a precise operating wavelength by setting various tuning signals according to values stored in memory.
Abstract:
An optical system comprising a randomizer that has a plurality of randomly positioned scatterers for scattering and thereby randomizing light to generate a speckle pattern and a detector for detecting the speckle pattern to determine at least one property of the light and/or change in at least one property of the light.
Abstract:
An optical system comprising a randomizer that has a plurality of randomly positioned scatterers for scattering and thereby randomizing light to generate a speckle pattern and a detector for detecting the speckle pattern to determine at least one property of the light and/or change in at least one property of the light.