Abstract: A laser-sustained plasma light source for transverse plasma pumping includes a pump source configured to generate pumping illumination, one or more illumination optical elements and a gas containment structure configured to contain a volume of gas. The one or more illumination optical elements are configured to sustain a plasma within the volume of gas of the gas containment structure by directing pump illumination along a pump path to one or more focal spots within the volume of gas. The one or more collection optical elements are configured to collect broadband radiation emitted by the plasma along a collection path. Further, the illumination optical elements are configured to define the pump path such that pump illumination impinges the plasma along a direction transverse to a direction of propagation of the emitted broadband light of the collection path such that the pump illumination is substantially decoupled from the emitted broadband radiation.

Abstract: An open plasma lamp includes a cavity section. A gas input and gas output of the cavity section are arranged to flow gas through the cavity section. The plasma lamp also includes a gas supply assembly fluidically coupled to the gas input of the cavity section and configured to supply gas to an internal volume of the cavity section. The plasma lamp also includes a nozzle assembly fluidically coupled to the gas output of the cavity section. The nozzle assembly and cavity section are arranged such that a volume of the gas receives pumping illumination from a pump source, where a sustained plasma emits broadband radiation. The nozzle assembly is configured to establish a convective gas flow from within the cavity section to a region external to the cavity section such that a portion of the sustained plasma is removed from the cavity section by the gas flow.

Abstract: A laser-sustained plasma light source includes a plasma cell configured to contain a volume of gas. The plasma cell is configured to receive illumination from a pump laser in order to generate plasma within the volume of gas. The plasma emits broadband radiation. The plasma cell includes one or more transparent portions being at least partially transparent to at least a portion of illumination from the pump laser and at least a portion of the broadband radiation emitted by the plasma. The plasma cell also includes one or more nanostructured layers disposed on one or more surfaces of the one or more transparent portions of the plasma cell. The one or more nanostructure layers form a region of refractive index control across an interface between the one or more transparent portions of the plasma cell and an atmosphere.

Abstract: A system for compensating abberative effects caused by a bulb of a plasma cell includes an illumination source configured to generate illumination; a plasma cell, the plasma cell including a bulb for containing a volume of gas; an ellipse configured to focus illumination from the illumination source into the volume of gas in order to generate a plasma within the volume of gas; and one or more adaptive optical elements configured to compensate for aberrations produced by one or more optical elements, the one or more adaptive optics elements positioned along an illumination pathway between the illumination source and the plasma cell.

Abstract: A laser sustained plasma light source having a cell formed as a continuous tube with a circular cross section, a gas volume contained within the cell, at least one laser directed into the gas volume, for sustaining a plasma within the gas volume, the plasma producing a light, where the gas volume is heated as it leaves the plasma, cools as it circulates around the continuous tube of the cell, and reenters the plasma cooler than when it left the plasma and in a laminar flow, and a reflector for collecting the light and providing the light to a desired location.

Abstract: A plasma cell for forming light-sustained plasma includes a transmission element configured to contain a volume of gas, a first terminal flange disposed at or near an opening of the transmission element, a second terminal flange disposed at or near another opening of the transmission element, a floating flange disposed between the first or second terminal flange and the transmission element. The floating flange is movable to compensate for thermal expansion of the transmission element. Further, the floating flange is configured to enclose the internal volume of the transmission element to contain a volume of gas within the transmission element. The transmission element is configured to receive illumination from an illumination source in order to generate plasma within the volume of gas. The transmission element is transparent to a portion of the illumination from the illumination source and a portion of broadband radiation emitted by the plasma.

Abstract: The inspection of a sample with VUV light from a laser sustained plasma includes generating pumping illumination including a first selected wavelength, or range of wavelength, containing a volume of gas suitable for plasma generation, generating broadband radiation including a second selected wavelength, or range of wavelengths, by forming a plasma within the volume of gas by focusing the pumping illumination into the volume of gas, illuminating a surface of a sample with the broadband radiation emitted from the plasma via an illumination pathway, collecting illumination from a surface of the sample, focusing the collected illumination onto a detector via a collection pathway to form an image of at least a portion of the surface of the sample and purging the illumination pathway and/or the collection pathway with a selected purge gas.

Abstract: A system for separating plasma pumping light and collected broadband light includes a pump source configured to generate pumping illumination including at least a first wavelength, a gas containment element for containing a volume of gas, a collector configured to focus the pumping illumination from the pumping source into the volume of gas to generate a plasma within the volume of gas, wherein the plasma emits broadband radiation including at least a second wavelength and an illumination separation prism element positioned between a reflective surface of the collector and the pump source and arranged to spatially separate the pumping illumination including the first wavelength and the emitted broadband radiation including at least a second wavelength emitted from the plasma.

Abstract: A plasma cell for controlling convection includes a transmission element configured to receive illumination from an illumination source in order to generate a plasma within a plasma generation region of the volume of gas. The plasma cell also includes a top flow control element disposed above the plasma generation, which includes an internal channel configured to direct a plume of the plasma upward, and a bottom flow control element disposed below the plasma generation region, which includes an internal channel configured to direct gas upward toward the plasma generation region. The top flow control element and the bottom flow control element are arranged within the transmission element to form one or more gas return channels for transferring gas from a region above the plasma generation region to a region below the plasma generation region.

Abstract: A laser-sustained plasma illuminator system includes at least one laser light source to provide light. At least one reflector focuses the light from the laser light source at a focal point of the reflector. An enclosure substantially filled with a gas is positioned at or near the focal point of the reflector. The light from the laser light source at least partially sustains a plasma contained in the enclosure. The enclosure has at least one wall with at least one property that is varied to compensate for optical aberrations in the system.

Abstract: A laser-sustained plasma illuminator system includes at least one laser light source to provide light. At least one reflector focuses the light from the laser light source at a focal point of the reflector. An enclosure substantially filled with a gas is positioned at or near the focal point of the reflector. The light from the laser light source at least partially sustains a plasma contained in the enclosure. The enclosure has at least one wall with a thickness that is varied to compensate for optical aberrations in the system.

Abstract: A system for controlling convective flow in a light-sustained plasma includes an illumination source configured to generate illumination, a plasma cell including a bulb for containing a volume of gas, a collector element arranged to focus illumination from the illumination source into the volume of gas in order to generate a plasma within the volume of gas contained within the bulb. Further, the plasma cell is disposed within a concave region of the collector element, where the collector element includes an opening for propagating a portion of a plume of the plasma to a region external to the concave region of the collect element.

Abstract: A laser-sustained plasma illuminator system includes at least one laser light source to provide light. At least one reflector focuses the light from the laser light source at a focal point of the reflector. An enclosure substantially filled with a gas is positioned at or near the focal point of the reflector. The light from the laser light source at least partially sustains a plasma contained in the enclosure. The enclosure has at least one wall with a thickness that is varied to compensate for optical aberrations in the system.

Abstract: A wafer inspection system includes a laser sustained plasma (LSP) light source that generates light with sufficient radiance to enable bright field inspection. Reliability of the LSP light source is improved by introducing an amount of water into the bulb containing the gas mixture that generates the plasma. Radiation generated by the plasma includes substantial radiance in a wavelength range below approximately 190 nanometers that causes damage to the materials used to construct the bulb. The water vapor acts as an absorber of radiation generated by the plasma in the wavelength range that causes damage. In some examples, a predetermined amount of water is introduced into the bulb to provide sufficient absorption. In some other examples, the temperature of a portion of the bulb containing an amount of condensed water is regulate to produce the desired partial pressure of water in the bulb.

Abstract: A fluid input manifold distributes injected fluid around the body of a bulb to cool the bulb below a threshold. The injected fluid also distributes heat more evenly along the surface of the bulb to reduce thermal stress. The fluid input manifold may comprise one or more airfoils to direct a substantially laminar fluid flow along the surface of the bulb or it may comprise a plurality of fluid injection nozzles oriented to produce a substantially laminar fluid flow. An output portion may be configured to facilitate fluid flow along the surface of the bulb by allowing injected fluid to easily escape after absorbing heat from the bulb or by applying negative pressure to actively draw injected fluid along the surface of the bulb and away.

Abstract: A method for sustaining a plasma includes providing a volume of a gas; generating illumination of a first selected wavelength; and forming a first plasma species in a first region of the gas and a second plasma species in a second region of the gas by focusing the illumination of the first wavelength into the volume of gas, the first region having a first average temperature and a first size, the second region having a second average temperature and a second size, the illumination of the first selected wavelength transmitted by the second plasma species, the illumination of the first selected wavelength absorbed by the first plasma species by tuning the first selected wavelength of the illumination to an absorption line of the first plasma species, the absorption line being associated with an ionic absorption transition or an excited neutral transition of the first plasma species.

Abstract: A wafer inspection system includes a laser sustained plasma (LSP) light source that generates light with sufficient radiance to enable bright field inspection. Reliability of the LSP light source is improved by introducing an amount of water into the bulb containing the gas mixture that generates the plasma. Radiation generated by the plasma includes substantial radiance in a wavelength range below approximately 190 nanometers that causes damage to the materials used to construct the bulb. The water vapor acts as an absorber of radiation generated by the plasma in the wavelength range that causes damage. In some examples, a predetermined amount of water is introduced into the bulb to provide sufficient absorption. In some other examples, the temperature of a portion of the bulb containing an amount of condensed water is regulate to produce the desired partial pressure of water in the bulb.

Abstract: A laser sustained plasma light source includes a plasma bulb containing a working gas flow driven by an electric current sustained within the plasma bulb. Charged particles are introduced into the working gas of the plasma bulb. An arrangement of electrodes maintained at different voltage levels drive the charged particles through the working gas. The movement of the charged particles within the working gas causes the working gas to flow in the direction of movement of the charged particles by entrainment. The resulting working gas flow increases convection around the plasma and increases laser to plasma interaction. The working gas flow within the plasma bulb can be stabilized and controlled by control of the voltages present on the each of the electrodes. A more stable flow of working gas through the plasma contributes to a more stable plasma shape and position within the plasma bulb.

Abstract: A laser-sustained light source having a first laser source for providing a first beam portion having a first characteristic, a second laser source for providing a second beam portion having a second characteristic, where the first characteristic is different from the first characteristic, first optics that are reflective to the first characteristic and transmissive of the second characteristic, for reflecting the first beam portion along a first path into a reflection optics and through a cell to sustain a plasma, second optics that are reflective to the second characteristic and transmissive of the first characteristic, for reflecting the second beam portion along a second path into the reflection optics and through the cell to sustain the plasma, the first path exiting to the second optics, where the first beam is transmitted through the second optics and into a beam dump, and the second path exiting to the first optics, where the second beam is transmitted through the first optics and into the beam dump.

Abstract: A method for sustaining a plasma includes providing a volume of a gas; generating illumination of a first selected wavelength; and forming a first plasma species in a first region of the gas and a second plasma species in a second region of the gas by focusing the illumination of the first wavelength into the volume of gas, the first region having a first average temperature and a first size, the second region having a second average temperature and a second size, the illumination of the first selected wavelength transmitted by the second plasma species, the illumination of the first selected wavelength absorbed by the first plasma species by tuning the first selected wavelength of the illumination to an absorption line of the first plasma species, the absorption line being associated with an ionic absorption transition or an excited neutral transition of the first plasma species.