Abstract: A method and system for reading a security seal having a unique far-field pattern are described. Periodic nano-structure is generated on the surface of a substrate having spacings of hundreds of nanometers, or smaller, and affixed on a product, or generated directly onto the product. A laser beam having a wavelength longer than the periodic spacings directed onto at least a portion of the surface of the substrate at a chosen angle of incidence and a selected azimuthal angle relative to a chosen direction produces a unique far-field pattern that may be imaged by a digital image detector disposed at a chosen distance from the illuminated region, compared with a stored reference, and validated. The nanoscale sub-wavelength patterns can be printed using extreme ultraviolet light and read with readily available visible or ultraviolet light. The security seal contains a pattern that is invisible to the eye and to an optical microscope.

Abstract: An apparatus and method for nanopatterning of substrates using the demagnified Talbot effect, wherein: (a) large arrays of nanostructures can rapidly be printed; (b) short extreme ultraviolet wavelengths permits sub-100 nm spatial resolution; (c) the de-magnification factor can be continuously adjusted, that is, continuously scaled; (d) the patterning is the effect of the collective diffraction of numerous tiled units that constitute the periodic array, giving rise to error resistance such that a defect in one unit is averaged over the area of the mask and the print does not show any defects; (e) the Talbot mask does not wear out since the method is non-contact; and (f) the feature sizes on the mask do not have to be as small as the feature sizes desired on the target, are described. The apparatus includes a source of coherent radiation having a chosen wavelength directed onto a focusing optic, the reflected converging light passing through a Talbot mask and impinging on a target substrate.

Abstract: A cryogenic cooling apparatus for high average power laser oscillator or amplifier, wherein the oscillator or amplifier material is in direct contact with a flowing cryogenic liquid cooled to below its boiling point is described. This method of cooling overcomes the limit in heat flux due to the onset of film boiling, thereby allowing for increased laser average power.

Abstract: An apparatus and method for nanopatterning of substrates using the demagnified Talbot effect, wherein: (a) large arrays of nanostructures can rapidly be printed; (b) short extreme ultraviolet wavelengths permits sub-100 nm spatial resolution; (c) the de-magnification factor can be continuously adjusted, that is, continuously scaled; (d) the patterning is the effect of the collective diffraction of numerous tiled units that constitute the periodic array, giving rise to error resistance such that a defect in one unit is averaged over the area of the mask and the print does not show any defects; (e) the Talbot mask does not wear out since the method is non-contact; and (f) the feature sizes on the mask do not have to be as small as the feature sizes desired on the target, are described. The apparatus includes a source of coherent radiation having a chosen wavelength directed onto a focusing optic, the reflected converging light passing through a Talbot mask and impinging on a target substrate.

Abstract: A method and system for reading a security seal having a unique far-field pattern are described. Periodic nano-structure is generated on the surface of a substrate having spacings of hundreds of nanometers, or smaller, and affixed on a product, or generated directly onto the product. A laser beam having a wavelength longer than the periodic spacings directed onto at least a portion of the surface of the substrate at a chosen angle of incidence and a selected azimuthal angle relative to a chosen direction produces a unique far-field pattern that may be imaged by a digital image detector disposed at a chosen distance from the illuminated region, compared with a stored reference, and validated. The nanoscale sub-wavelength patterns can be printed using extreme ultraviolet light and read with readily available visible or ultraviolet light. The security seal contains a pattern that is invisible to the eye and to an optical microscope.

Abstract: An apparatus and method for nanopatterning of substrates using the demagnified Talbot effect, wherein: (a) large arrays of nanostructures can rapidly be printed; (b) short extreme ultraviolet wavelengths permits sub-100 nm spatial resolution; (c) the de-magnification factor can be continuously adjusted, that is, continuously scaled; (d) the patterning is the effect of the collective diffraction of numerous tiled units that constitute the periodic array, giving rise to error resistance such that a defect in one unit is averaged over the area of the mask and the print does not show any defects; (e) the Talbot mask does not wear out since the method is non-contact; and (f) the feature sizes on the mask do not have to be as small as the feature sizes desired on the target, are described. The apparatus includes a source of coherent radiation having a chosen wavelength directed onto a focusing optic, the reflected converging light passing through a Talbot mask and impinging on a target substrate.

Abstract: Ablation of holes having diameters as small as 82 nm and having clean walls was obtained in a poly(methyl methacrylate) on a silicon substrate by focusing pulses from a Ne-like Ar, 46.9 nm wavelength, capillary-discharge laser using a freestanding Fresnel zone plate diffracting into third order is described. Spectroscopic analysis of light from the ablation has also been performed. These results demonstrate the use of focused coherent EUV/SXR light for the direct nanoscale patterning of materials.

Abstract: Ablation of holes having diameters as small as 82 nm and having clean walls was obtained in a poly(methyl methacrylate) on a silicon substrate by focusing pulses from a Ne-like Ar, 46.9 nm wavelength, capillary-discharge laser using a freestanding Fresnel zone plate diffracting into third order is described. Spectroscopic analysis of light from the ablation has also been performed. These results demonstrate the use of focused coherent EUV/SXR light for the direct nanoscale patterning of materials.

Abstract: A pre-ionized medium created by a capillary discharge results in more efficient use of laser energy in high-order harmonic generation (HHG) from ions. It extends the cutoff photon energy, and reduces the distortion of the laser pulse as it propagates down the waveguide. The observed enhancements result from a combination of reduced ionization energy loss and reduced ionization-induced defocusing of the driving laser as well as waveguiding of the driving laser pulse. The discharge plasma also provides a means to spectrally tune the harmonics by tailoring the initial level of ionization of the medium.

Abstract: Direct patterning of nanometer scale features by interferometric lithography using a 46.9 nm laser is described. Multiple exposures using a Lloyd's mirror interferometer permitted printing of arrays having 60 nm FWHM features.

Abstract: An extreme ultraviolet/soft x-ray laser driven by a compact solid-state chirped pulse amplification laser system entirely pumped by laser diodes is described. The solid-state pump laser generates compressed pulses of sub-10 ps duration with energy greater than 1 J at a chosen repetition rate in a cryogenically cooled Yb:YAG system. Lasing in the 18.9 nm line of Ni-like Mo was observed. The diode-pumped laser has the potential to greatly increase the repetition rate and average power of lasers having a variety of EUV/SXR wavelengths on a significantly smaller footprint.

Abstract: Generation of 2 ?W average output power at 13.9 nm from a table-top laser-pumped Ni-like Ag laser operating at 5 Hz repetition rate using a silver-coated helical target which is rotated and advanced such that the target surface is renewed between pulses, is described. Greater than 2×104 soft x-ray laser pulses were obtained using a single target. Similar results were obtained at 13.2 nm for Ni-like Cd using a cadmium-coated target. Uninterrupted operation of laser-pumped soft x-ray lasers at a repetition rates of about 10 Hz for periods of several hours enables the generation of pulsed, high average power soft x-rays for applications. Other embodiments of the renewable laser target are described.

Abstract: Generation of 2 ?W average output power at 13.9 nm from a table-top laser-pumped Ni-like Ag laser operating at 5 Hz repetition rate using a silver-coated helical target which is rotated and advanced such that the target surface is renewed between pulses, is described. Greater than 2×104 soft x-ray laser pulses were obtained using a single target. Similar results were obtained at 13.2 nm for Ni-like Cd using a cadmium-coated target. Uninterrupted operation of laser-pumped soft x-ray lasers at a repetition rates of about 10 Hz for periods of several hours enables the generation of pulsed, high average power soft x-rays for applications. Other embodiments of the renewable laser target are described.

Abstract: Direct patterning of nanometer scale features by interferometric lithography using a 46.9 nm laser is described. Multiple exposures using a Lloyd's mirror interferometer permitted printing of arrays having 60 nm FWHM features.

Abstract: Saturated tabletop lasers having increased output energy and operating at 5 Hz repetition rate, were demonstrated at wavelengths about 18.9 nm for molybdenum targets, 16.4 nm for ruthenium targets, 14.7 nm for palladium targets, 13.9 nm for silver targets, and 13.2 nm for cadmium targets in transitions of nickel-like ions. The results were obtained using a sequence of two, plasma-generating pre-pulses, each having sub-Joule energy followed after a selected delay period by picosecond laser plasma excitation pulses having with an energy of about 1 J at angles of incidence optimized for maximum energy deposition.

Abstract: A compact, high repetition rate, extreme ultraviolet/soft x-ray laser and method for generating such radiation are described. Excitation of the gaseous or vaporous lasing medium is achieved by discharging energy stored in a solid-dielectric capacitive device through a capillary channel containing the medium. By reducing the inductance of the discharge apparatus, excitation of the laser medium can be achieved without the use of Marx generators. Neon-like Ar atom laser pulses at 46.9 nm having energies of about 13 ?J are generated at repetition rates up to 12 Hz. Between 2 and 3×104 laser shots can be generated using a single capillary. Such a source of intense, short-wavelength radiation can be used for applications which include surface characterization of materials, high resolution imaging and printing, photochemistry and photophysics, laser ablation, characterization of x-ray optics, and dense plasma diagnostics.

Abstract: The generation of soft x-ray and/or extreme untraviolet laser radiation is accomplished in a capillary plasma generated by a fast discharge. The method yields laser action at short wavelengths in a discharge created plasma having a large length-to-diameter ratio.

Abstract: A highly efficient laser employs a glow discharge electron gun and includes a solid wall cathode that emits a beam of electrons resulting in a plasma that is a negative glow discharge having an electron distribution that has a larger number of high energy electrons than would be present in a Maxwellian distribution of the same electron density.

Abstract: Applicants have invented a new low temperature method (50.degree. C. to 500.degree. C.) to deposit and grow microelectronic thin films using cold cathode electron beams to initiate and sustain both gas phase and surface chemical reactions. The new method uses electron beams generated by glow discharge electron guns. Secondary electrons are emitted from these electron guns following ion and fast neutral bombardment upon cathode surfaces and secondary electrons so formed are accelerated in the cathode sheath.Our method uses the plasma generated electron beams to decompose reactant molecules directly by electron impact and indirectly by the vacuum ultraviolet radiation generated following rare gas electron collisions in the beam region. The reactant molecules can be in the gas phase or adsorbed on substrate surfaces. The electron beams are spatially confined and excite only a localized region above the substrate so that direct plasma bombardment of the substrate is avoided.

Abstract: A new apparatus for altering the microtopography of certain solid materials commonly used in the integrated circuit industry by electron beam induced etching is described. This is accomplished with one or more glow discharge electron beam guns operating in a controlled gas environment. Specially designed versions of these guns perform the dual functions of dissociating certain donors of reactive gases in close proximity to the substrate surface and enhancing surface reactions anisotropically with the directed electron beam energy. The geometrical relationship between the substrate and the electron beams is chosen to optimize the role of each beam for its particular function. The operating gas environment is typically a carefully controlled mixture of a non-reactive buffer gas and one or more reactive gases. The gas flow rates, partial pressures, and direction are controlled by valves, regulators, and nozzles connected to the low pressure vessel.