Abstract: A mode-locked laser system operable at low temperature can include an annealed, frequency-conversion crystal and a housing to maintain an annealed condition of the crystal during standard operation at the low temperature. In one embodiment, the crystal can have an increased length. First beam shaping optics can be configured to focus a beam from a light source to an elliptical cross section at a beam waist located in or proximate to the crystal. A harmonic separation block can divide an output from the crystal into beams of different frequencies separated in space. In one embodiment, the mode-locked laser system can further include second beam shaping optics configured to convert an elliptical cross section of the desired frequency beam into a beam with a desired aspect ratio, such as a circular cross section.

Abstract: A pulse multiplier includes a polarizing beam splitter, a wave plate, and a set of mirrors. The polarizing beam splitter receives an input laser pulse. The wave plate receives light from the polarized beam splitter and generates a first set of pulses and a second set of pulses. The first set of pulses has a different polarization than the second set of pulses. The polarizing beam splitter, the wave plate, and the set of mirrors create a ring cavity. The polarizing beam splitter transmits the first set of pulses as an output of the pulse multiplier and reflects the second set of pulses into the ring cavity. This pulse multiplier can inexpensively reduce the peak power per pulse while increasing the number of pulses per second with minimal total power loss.

Abstract: An enclosure that maintains the environment of one or more optical crystals and allows efficient frequency conversion for light at wavelengths at or below 400 nm with minimal stress being placed on the crystals in the presence of varying temperatures. Efficient conversion may include multiple crystals of the same or different materials. Multiple frequency conversion steps may also be employed within a single enclosure. Materials that have been processed specifically to provide increased lifetimes, stability, and damage thresholds over designs previously available are employed. The enclosure allows pre-exposure processing of the crystal(s) such as baking at high temperatures and allowing real time measurement of crystal properties.

Abstract: An enclosure that maintains the environment of one or more optical crystals and allows efficient frequency conversion for light at wavelengths at or below 400 nm with minimal stress being placed on the crystals in the presence of varying temperatures. Efficient conversion may include multiple crystals of the same or different materials. Multiple frequency conversion steps may also be employed within a single enclosure. Materials that have been processed specifically to provide increased lifetimes, stability, and damage thresholds over designs previously available are employed. The enclosure allows pre-exposure processing of the crystal(s) such as baking at high temperatures and allowing real time measurement of crystal properties.

Abstract: The present invention includes a fundamental laser light source configured to generate fundamental wavelength laser light, a first nonlinear optical crystal configured to generate first alternate wavelength light; a second nonlinear optical crystal configured to generate second alternate wavelength light; a dual wavelength Brewster angle waveplate configured to rotate a polarization of the first alternate wavelength light relative to the second alternate wavelength light such that the first and second alternate wavelength light have the same polarization; a set of Brewster angle wavefront processing optics configured to condition the first and second alternate wavelengths of light; a harmonic separator configured to separate the first alternate wavelength light from the second alternate wavelength light; and a Brewster angle output window configured to transmit the first or second alternate wavelengths of light from the interior of a laser frequency conversion system to the exterior of the laser frequency con

Abstract: The present invention includes a fundamental laser light source configured to generate fundamental wavelength laser light, an optical crystal configured to receive fundamental laser light from the fundamental laser light source, the optical crystal configured to generate alternate wavelength light by frequency converting a portion of the received fundamental laser light to alternate wavelength light, an auxiliary light source configured to generate auxiliary wavelength light, the auxiliary wavelength light having a wavelength different from the fundamental wavelength laser light and the alternate wavelength light, the fundamental laser light source and the auxiliary light source oriented such that the fundamental laser light copropagates with the auxiliary light through a surface of the optical crystal, and a detector configured to detect at least one of fundamental wavelength laser light scattered by the optical crystal, alternate wavelength light scattered by the optical crystal, or auxiliary light scattere

Abstract: The present invention is directed to a laser system in which a current laser wavefront performance of the laser system may be monitored. Further, the laser system embodiments disclosed herein may be configured for correcting the laser wavefront internally via correction system(s) within the laser system. Still further, the correction system(s) disclosed herein may provide a long lifetime of performance and may be configured for having a minimal impact on photocontamination.

Abstract: The present invention is directed to a beam dump which is configured for not increasing a temperature of a laser with which it may be implemented. The beam dump may include an opaque enclosure which is configured for receiving light (ex.—initial light) from a light source (ex.—a frequency-converted laser), said light being delivered through an aperture of the enclosure via one or more connected optical fibers. The received light may be scattered within the enclosure. However, the beam dump is configured for minimizing the amount of light which is back scattered light into the fiber(s). For instance, the amount of back scattered light may be less than 1/1000 of the initial light. Further, the beam dump may be configured for minimizing photocontamination which may be caused when the light contacts interior surfaces of the enclosure. Still further, the beam dump may be a small size, low cost structure.

Abstract: A system for inspecting a specimen is provided. The system includes an illumination subsystem configured to produce a plurality of channels of light energy, each channel of light energy produced having differing characteristics (type, wavelength, etc.) from at least one other channel of light energy. Optics are configured to receive the plurality of channels of light energy and combine them into a spatially separated combined light energy beam and direct it toward the specimen. A data acquisition subsystem comprising at least one detector is provided, configured to separate reflected light energy into a plurality of received channels corresponding to the plurality of channels of light energy and detect the received channels.

Abstract: A laser illuminator for use in an inspection system, such as a semiconductor wafer inspection system or photomask inspection system is provided. The gain medium in the illuminator comprises optical fiber, and amplification, beam splitting, frequency and/or bandwidth conversion, peak power reduction, and q-switching or mode locking may be employed. Certain constructs including doped fiber, gratings, saturable absorbers, and laser diodes are disclosed to provide enhanced illumination.

Abstract: An improved inspection system using back-side illuminated linear sensing for propagating charge through a sensor is provided. Focusing optics may be used with a back side illuminated linear sensor to inspect specimens, the back side illuminated linear sensor operating to advance an accumulated charge from one side of each pixel to the other side. The design comprises controlling voltage profiles across pixel gates from one side to the other side in order to advance charge between to a charge accumulation region. Controlling voltage profiles comprises attaching a continuous polysilicon gate across each pixel within a back side illuminated linear sensor array. Polysilicon gates and voltages applied thereto enable efficient electron advancement using a controlled voltage profile.

Abstract: An inspection system including a catadioptric objective that facilitates dark-field inspection is provided. The objective includes an outer element furthest from the specimen having an outer element partial reflective surface oriented toward the specimen, an inner element nearest the specimen having a center lens comprising an inner element partial reflective surface oriented away from the specimen, and a central element positioned between the outer lens and the inner lens. At least one of the outer element, inner element, and central element has an aspheric surface. The inner element is spatially configured to facilitate dark-field inspection of the specimen.

Abstract: An objective for imaging specimens is disclosed. The objective receives light energy from a light energy source configured to provide light energy in a wavelength range of approximately 480 to 660 nanometers, employs a Mangin mirror arrangement in conjunction with an immersion liquid to provide a numerical aperture in excess of 1.0 and a field size in excess of 0.05 millimeters, where every element in the objective has a diameter of less than approximately 40 millimeters.

Abstract: A relatively high NA objective employed for use in imaging a specimen is provided. The objective includes a lens group having at least one focusing lens configured to receive light energy and form an intermediate image, at least one field lens oriented to receive the intermediate image and provide intermediate light energy, and a Mangin mirror arrangement positioned to receive the intermediate light energy and apply light energy to the specimen. One or more elements may employ an aspheric surface. The objective may provide an uncorrected spectral bandwidth up to approximately 193 to 266 nanometers and numerical apertures in excess of 0.9. Elements are less than 100 millimeters in diameter and may fit within a standard microscope. The field lens may include more than one lens and may be formed of a material different from at least one other lens in the objective.

Abstract: A method and apparatus for inspecting a specimen are provided. The apparatus comprises a primary illumination source, a catadioptric objective exhibiting central obscuration that directs light energy received from the primary illumination source at a substantially normal angle toward the specimen, and an optical device, such as a prism or reflective surface, positioned within the central obscuration resulting from the catadioptric objective for receiving further illumination from a secondary illumination source and diverting the further illumination to the specimen. The method comprises illuminating a surface of the specimen at a variety of angles using a primary illumination source, illuminating the surface using a secondary illumination source, the illuminating by the secondary illumination source occurring at a substantially normal angle of incidence; and imaging all reflected, scattered, and diffracted light energy received from the surface onto a detector.

Abstract: A catadioptric objective configured to inspect a specimen is provided. The catadioptric objective includes a Mangin element having one surface at a first axial location and an extension element positioned together with the Mangin element. The extension element provides a second surface at a second axial location. Certain light energy reflected from the specimen passes to the second surface of the extension element, the Mangin element, and through a plurality of lenses. An aspheric surface may be provided, and light energy may be provided to the specimen using diverting elements such as prisms or reflective surfaces.

Abstract: A system and method for inspecting a specimen, such as a semiconductor wafer, including illuminating at least a portion of the specimen using an excimer source using at least one relatively intense wavelength from the source, detecting radiation received from the illuminated portion of the specimen, analyzing the detected radiation for potential defects present in the specimen portion.

Abstract: A reduced size catadioptric objective and system is disclosed. The objective may be employed with light energy having a wavelength in the range of approximately 190 nanometers through the infrared light range. Elements are less than 100 mm in diameter. The objective comprises a focusing lens group configured to receive the light energy, at least one field lens oriented to receive focused light energy from the focusing lens group and provide intermediate light energy, and a Mangin mirror arrangement positioned to receive the intermediate light energy from the field lens and form controlled light energy for transmission to a specimen. The Mangin mirror arrangement imparts controlled light energy with a numerical aperture in excess of 0.65 and up to approximately 0.90, and the design may be employed in various environments.

Abstract: A relatively high spectral bandwidth objective employed for use in imaging a specimen and method for imaging a specimen is provided. The objective includes a lens group having at least one focusing lens configured to receive light energy and form an intermediate image, at least one field lens oriented to receive the intermediate image and provide intermediate light energy, and a Mangin mirror arrangement positioned to receive the intermediate light energy and apply light energy to the specimen. The objective may provide, in certain instances, a spectral bandwidth up to approximately 193 to 266 nanometers and can provide numerical apertures in excess of 0.9. Elements are less than 100 millimeters in diameter and may fit within a standard microscope. The field lens may include more than one lens and may be formed of a material different from at least one other lens in the objective.

Abstract: A relatively high spectral bandwidth objective employed for use in imaging a specimen and method for imaging a specimen is provided. The objective includes a lens group having at least one focusing lens configured to receive light energy and form focused light energy. The focused light energy forms an intermediate image. The objective further includes at least one field lens located in proximity to an intermediate image, and a catadioptric arrangement positioned to receive the intermediate light energy from the at and form controlled light energy. The catadioptric arrangement may include at least one Mangin element and can include a meniscus lens element.