Cell for light source

A vacuum ultraviolet plasma light source, comprising:

• a cell comprising,
• a tube having cylindrical side walls and formed exclusively of sapphire,
• a first substantially flat end cap and a second substantially flat end cap diffusion bonded to opposing ends of the tube, the first and second end caps formed exclusively of sapphire, the end caps and the tube forming a closed cell,
• the first end cap disposed substantially perpendicular to the side walls of the tube, and the second end cap disposed oblique to the side walls of the tube,
• the second end cap coated with an anti-reflective coating so that the laser light directed into the cell through the coated second end cap exhibits a reduced degree of reflectance, and the first end cap not coated with the anti-reflective coating,
• the first end cap having a first purity grade of sapphire and the second end cap having a second purity grade of sapphire, where the first purity grade of sapphire is relatively greater than the second purity grade of sapphire,
• the second end cap for receiving a laser light along a second trajectory that is substantially perpendicular to the second end cap,
• the cell containing at least one noble gas that is ionizable to a plasma for producing an ultraviolet light, and
• the first end cap for expelling the ultraviolet light along a first trajectory that is substantially perpendicular to the first end cap, and askew to the second trajectory,
• means for initiating the plasma within the cell, and
• means for sustaining the plasma within the cell.

A spectrographic instrument, comprising:

• a vacuum ultraviolet plasma light source, comprising,
• a cell comprising,
• a tube having cylindrical side walls and formed exclusively of sapphire,
• a first substantially flat end cap and a second substantially flat end cap diffusion bonded to opposing ends of the tube, the first and second end caps formed exclusively of sapphire, the end caps and the tube forming a closed cell,
• the first end cap disposed substantially perpendicular to the side walls of the tube, and the second end cap disposed oblique to the side walls of the tube,
• the second end cap coated with an anti-reflective coating so that the laser light directed into the cell through the coated second end cap exhibits a reduced degree of reflectance, and the first end cap not coated with the anti-reflective coating,
• the first end cap having a first purity grade of sapphire and the second end cap having a second purity grade of sapphire, where the first purity grade of sapphire is relatively greater than the second purity grade of sapphire,
• the second end cap for receiving a laser light along a second trajectory that is substantially perpendicular to the second end cap,
• the cell containing at least one noble gas that is ionizable to a plasma for producing a vacuum ultraviolet light, and
• the first end cap for expelling the ultraviolet light along a first trajectory that is substantially perpendicular to the first end cap, and askew to the second trajectory,
• means for initiating the plasma within the cell, and
• means for sustaining the plasma within the cell,
• a polarizer for imparting a desired polarization to the vacuum ultraviolet light,
• optical elements for directing the polarized vacuum ultraviolet light to impinge upon and reflect from a substrate,
• optical elements for receiving the reflected polarized vacuum ultraviolet light from the substrate,
• an analyzer for filtering portions of the reflected polarized vacuum ultraviolet light, and
• a spectrometer for creating signals associated with the filtered reflected polarized vacuum ultraviolet light.