Emission Of Extreme Ultraviolet Light Research Articles

Ultrafast Resonant State Formation by the Coupling of Rydberg and Dark Autoionizing States.

Studying the dynamics of dark states is challenging due to their inability to undergo single-photon emission or absorption. This challenge is made even more difficult for dark autoionizing states owing to their ultrashort lifetime of a few femtoseconds. High-order harmonic spectroscopy recently appeared as a novel method to probe the ultrafast dynamics of a single atomic or molecular state. Here, we demonstrate the emergence of a new type of ultrafast resonance state as a manifestation of coupling between Rydberg and a dark autoionizing state dressed by a laser photon. Through high-order harmonic generation, this resonance results in extreme ultraviolet light emission that is more than one order of magnitude stronger than for the off-resonance case. The induced resonance can be leveraged to study the dynamics of a single dark autoionizing state and the transient changes in the dynamics of real states due to their overlap with the virtual laser-dressed states. In addition, the present results allow the generation of coherent ultrafast extreme ultraviolet light for advanced ultrafast science applications.

Optimization of Extreme Ultraviolet Emission from Laser-Produced Tin Plasmas Based on Radiation Hydrodynamics Simulations

We investigated the plasma conditions for obtaining highly efficient extreme ultraviolet light from laserproduced tin plasmas for lithography of next generation semiconductors. Based on accurate atomic data tables calculated using the detailed configuration accounting code, we conducted 1-D radiation hydrodynamic simulations to calculate the dynamics of tin plasma and its emission of extreme ultraviolet light. We included the photo-excitation effect in the radiation transport. Our simulation reproduced experimental observations successfully. Using our verified code, we found that a CO2 laser can be useful in obtaining higher conversion efficiencies up to 4%.

Sn O 2 target with controllable microstructure and thickness for generating extreme ultraviolet light

The target of weaved tin-oxide nanofibers were fabricated by electrospinning method. The microstructure, density, and thickness of the tin-oxide fibers could be well controlled by different fabrication condition. Extreme ultraviolet emission from Sn and SnO2 nanofibers was experimentally investigated. It was found that the microscopic structure of the target could have great affection on the extreme ultraviolet light emission.

Formation of a hydrogen plasma from an incandescently heated hydrogen-catalyst gas mixture with an anomalous afterglow duration

We report the generation of a plasma of hydrogen and certain alkali ions as recorded via EUV spectroscopy and the hydrogen Balmer and alkali line emissions in the visible range. Typically, a hydrogen plasma is generated and the emission of extreme ultraviolet light from hydrogen gas is achieved via a discharge at high voltage, a high power inductively-coupled plasma, or a plasma created and heated to extreme temperatures by RF coupling (e.g. >10 6 K) with confinement provided by a toroidal magnetic field. The observed plasma formed at low temperatures (e.g. ≈10 3 K) from atomic hydrogen generated at a tungsten filament that heated a titanium dissociator and a catalyst comprising one of potassium, rubidium, cesium, and their carbonates and nitrates. These atoms and ions ionize to provide a catalyst with a net enthalpy of reaction of an integer multiple of the potential energy of atomic hydrogen (m×27.2 eV , m=integer) to within 0.17 eV and comprise only a single ionization in the case of a potassium or rubidium ion. Whereas, the chemically similar atoms of sodium and sodium and lithium carbonates and nitrates which do not ionize with these constraints caused no emission. To test the electric dependence of the emission, the weak electric field of about 1 V/ cm was set and measured to be zero in <0.5×10 −6 s . An anomalous afterglow duration of about 1–2 s was recorded in the case of potassium, rubidium, cesium, K 2 CO 3, RbNO 3 , and CsNO 3. Hydrogen line or alkali line emission was occurring even though the voltage between the heater wires was set to and measured to be zero. These atoms and ions ionize to provide a catalyst with a net enthalpy of reaction of an integer multiple of the potential energy of atomic hydrogen to within less than the thermal energies at ≈10 3 K and comprise only a single ionization in the case of a potassium or rubidium ion. Since the thermal decay time of the filament for dissociation of molecular hydrogen to atomic hydrogen was similar to the anomalous plasma afterglow duration, the emission was determined to be due to a reaction of atomic hydrogen with a catalyst that did not require the presence of an electric field to be functional.

Observation of extreme ultraviolet hydrogen emission from incandescently heated hydrogen gas with strontium that produced an anomalous optically measured power balance

We report the observation of intense extreme ultraviolet (EUV) emission from incandescently heated atomic hydrogen and atomized strontium. It has been reported that intense EUV emission was observed at low temperatures (e.g. ≈10 3 K ) from atomic hydrogen and certain atomized elements or certain gaseous ions which ionize at integer multiples of the potential energy of atomic hydrogen, 27.2 eV [1–5]. Strontium ionizes at integer multiples of the potential energy of atomic hydrogen. Typically the emission of extreme ultraviolet light from hydrogen gas is achieved via a discharge at high voltage, a high-power inductively coupled plasma, or a plasma created and heated to extreme temperatures by RF coupling (e.g. >10 6 K ) with confinement provided by a toroidal magnetic field. The observed plasma formed at low temperatures (e.g. ≈10 3 K ) from atomic hydrogen generated at a tungsten filament that heated a titanium dissociator and atomic strontium which was vaporized from the metal by heating. No emission was observed when sodium, magnesium, or barium replaced strontium or with hydrogen or strontium alone. The power balance of a gas cell having atomized hydrogen and strontium was measured by integrating the total light output corrected for spectrometer system response and energy over the visible range. A control cell was identical except that sodium replaced strontium. In this case, 4000 times the power of the strontium cell was required in order to achieve that same optically measured light output power. A plasma formed at a cell voltage of about 250 V in the cell with hydrogen alone and in the cell with hydrogen and sodium; whereas, a plasma formed in the strontium cell at the extremely low voltage of about 2 V.

Temporal behavior of light-emission in the visible spectral range from a Ti–K 2CO 3–H cell

We report the generation of a hydrogen plasma and extreme ultraviolet emission as recorded via the hydrogen Balmer emission in the visible range. Typically, a hydrogen plasma is generated and the emission of extreme ultraviolet light from hydrogen gas is achieved via a discharge at high voltage, a high-power inductively coupled plasma, or a plasma created and heated to extreme temperatures by RF coupling (e.g. >10 6 K ) with confinement provided by a toroidal magnetic field. The observed plasma formed at low temperatures (e.g. ≈10 3 K ) from atomic hydrogen generated at a tungsten filament that heated a titanium dissociator coated with potassium carbonate. The temporal behavior of the plasma was recorded via hydrogen Balmer α line emission when all power into the cell was terminated. A 2 s decay of the plasma was observed after a fast decay of the electric field to zero. The persistence of emission following the removal of all of the power to the cell indicates that a novel chemical power source is present that forms an energetic plasma in hydrogen. No unusual behavior was observed with the control sodium carbonate.

Observation of extreme ultraviolet hydrogen emission from incandescently heated hydrogen gas with certain catalysts

Typically the emission of extreme ultraviolet light from hydrogen gas is achieved via a discharge at high voltage, a high power inductively coupled plasma, or a plasma created and heated to extreme temperatures by RF coupling (e.g. >10 6 K) with confinement provided by a toroidal magnetic field. We report the observation of intense extreme ultraviolet (EUV) emission at low temperatures (e.g. <10 3 K) from atomic hydrogen and certain atomized pure elements or certain gaseous ions which ionize at integer multiples of the potential energy of atomic hydrogen.