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We have demonstrated the photon-stimulated surface spectroscopy using broadband vacuum ultraviolet (VUV) emissions from a laser-produced plasma, in which adsorbed atoms or molecules on material surfaces were to be desorbed and dissociated as a result of absorption of the wavelength-selected VUV photons. Desorbed and dissociated atoms or molecules were then detected by a mass spectrometer. Mass spectra of polyethylene and polyvinyl chloride samples were obtained as a function of the irradiation wavelength. We have found sufficient characteristic differences of the mass spectra in the irradiation wavelength shorter than 200 nm in each sample. The desorption and dissociation of atoms or molecules from material surfaces depended on bond energy or molecular structure. [ABSTRACT FROM AUTHOR]

Corrosion-, chemical-resistant pure iron thin films were formed by the vacuum ultraviolet fluorine laser of 157 nm wavelength induced surface modification of 30- to 50-nm-thick iron thin films. Transmission electron microscope and electron energy-loss spectroscopy were conducted to analyze structure and oxidation state of the thin modified layer of iron thin films. No rust was observed on the surface of the fluorine laser-irradiated iron thin films in air for 2 years. The samples also showed high chemical resistance to a HNO aqueous solution to fabricate a micropattern of pure iron thin films. [ABSTRACT FROM AUTHOR]

Vacuum ultraviolet (VUV) radiation around 159 nm is obtained toward direct excitation of a single trapped $$^{115}\hbox {In}^{+}$$ ion. An efficient fluoride-based VUV output coupler is employed for intracavity high-harmonic generation of a Ti:S oscillator. Using this coupler, where we measured its reflectance to be about 90 %, an average power reaching 6.4 $$\upmu$$ W is coupled out from a modest fundamental power of 650 mW. When a single comb component out of 1.9 $$\times$$ 10 $$^{5}$$ teeth is resonant to the atomic transition, 100s of fluorescence photons per second will be detectable under a realistic condition. [ABSTRACT FROM AUTHOR]

Continuous coherent radiation in the vacuum ultraviolet at 122 nm (Lyman-α) can be generated using sum-frequency mixing of three fundamental laser beams in mercury vapor. One of the fundamental beams is at 254 nm wavelength, which is close to the 6 1S0–6 3P1 resonance in mercury. Experiments have been performed to investigate the effect of this one-photon resonance on phase-matching, absorption and the nonlinear yield. The efficiency of continuous Lyman-α generation has been improved by a factor of 4.5. [ABSTRACT FROM AUTHOR]

We have demonstrated proof-of-principle of an incoherent ArF ∗ emission source with a quasi-point emission geometry using a laser-produced plasma in an Ar/F 2/He/Ne mixed gas. The VUV emission characteristics, such as the emission size, were dependent on those of the plasma-initiating laser. The average emission power was 10 μW at a repetition rate of 10 Hz at 193 nm. The average power conversion efficiency of the 193-nm emission from the plasma-initiating Nd:YAG laser was 6.3×10 −6. The average emission power at 193 nm was proportional to that of the plasma-initiating laser, indicating the scaling of the emission source. [ABSTRACT FROM AUTHOR]

The efficiency of a coherent vacuum ultraviolet (VUV) source at 125 nm, based on two-photon resonant four-wave mixing in mercury vapor, has been enhanced by up to two orders of magnitude. This enhancement was obtained by locally heating a liquid mercury surface with a pulsed excimer laser, resulting in a high-density vapor plume in which the nonlinear interaction occurred. Energies up to 5 μJ (1 kW peak power) have been achieved while keeping the overall mercury cell at room temperature, avoiding the use of a complex heat pipe. We have observed a strong saturation of the VUV yield when peak power densities of the fundamental beams exceeded the GW/cm2 range, as well as a large intensity-dependent broadening (up to ∼ 30 cm-1) of the two-photon resonance. The source has potential applications for high-resolution interference lithography and photochemistry. [ABSTRACT FROM AUTHOR]

A new pump scheme for the realization of a practical Ar[sub 2] excimer laser operating at 126 nm has been proposed and investigated experimentally. In this scheme, pre-ionized high-pressure Ar gas was excited by an intense transversely-excited atmospheric (TEA) CO[sub 2] laser irradiation. A 100-mm-long line plasma was successfully produced at an argon gas pressure of 2 MPa. The vacuum ultraviolet emission at 126 nm from the Ar[sub 2] excimers was observed and its emission characteristics were investigated under various experimental conditions. [ABSTRACT FROM AUTHOR]

Abstract. We have developed a vacuum ultraviolet (VUV) lamp at 134 nm with a quasi-point emission geometry using a quasi-continuous-wave (cw) gas jet discharge of an Ar/Kr gas mixture. We have unambiguously identified a new emission continuum centered at 134 nm as a transition of Ar-Kr hetero-nuclear excimers (ArKr[sup *]). The VUV emission power of the 134 nm continuum was 10 mW at 21 atm of the total Ar/Kr stagnation gas pressure, at a Kr concentration of 0.1%. Characteristic energy transfer between atoms and dimers plays an important role for the efficient production of ArKr[sup *] in such a gas jet discharge. [ABSTRACT FROM AUTHOR]

When the laser frequency was tuned through the H[sup 2] Σ[sup +] ,H[sup ′2] Π(v[sup ′] =0)←X[sup 2] Π(v[sup ′′] =0) two-photon transition of NO, both near-infrared and vacuum ultraviolet radiation were emitted along the laser propagation direction. The analyses of emission and excitation spectra revealed that the parametric four-wave mixing (PFWM) process coexisted with amplified spontaneous emission. Polarization properties of the IR radiation are found to be dependent on the rotational levels. Pressure and laser power behaviors of the generated waves were reported. The mechanism of PFWM was discussed in terms of selection rules of the relevant ro-vibronic transitions. [ABSTRACT FROM AUTHOR]

We present measurements of the net-induced gain on the 5d–4f transition at 186 nm in LiYF[sub 4] : Nd[sup 3+] optically pumped by radiation from a molecular fluorine laser. It is found that for LiYF[sub 4] : Nd[sup 3+] , one of a series of potential continuously tunable VUV lasers, relatively strong excited-state absorption results in net-induced loss. The prospects for VUV laser operation being realised in other rare-earth-doped fluorides is discussed. [ABSTRACT FROM AUTHOR]