B. R. Benware

Generation of millijoule-level soft-x-ray laser pulses at a 4-Hz repetition rate in a highly saturated tabletop capillary discharge amplifier

Laser pulses with energies of as much as 1 mJ were generated at a wavelength of 46.9 nm by single-pass amplification in a 34.5 cm-long Ne-like Ar capillary discharge plasma. The large gain–length product of this plasma column allows for soft-x-ray amplification in a highly saturated regime, resulting in efficient energy extraction. Average laser output pulse energy of 0.88 mJ and peak power of 0.6 MW were obtained at a repetition rate of 4 Hz. With an estimated peak spectral brightness of ?1×1023 photons/(s mm2 mrad2 0.01% bandwidth) this tabletop laser is one of the brightest soft-x-ray sources to date.

Focusing of a tabletop soft-x-ray laser beam and laser ablation

We focused the beam of a high-repetition-rate capillary-discharge tabletop laser operating at a wavelength of 46.9 nm, using a spherical Si/Sc multilayer mirror. The energy densities significantly exceeded the thresholds for the ablation of metals. Single-shot laser ablation patterns were used in combination with ray-tracing computations to characterize the focused beam. The radiation intensity within the 2-mum -diameter central region of the focal spot was estimated to be approximately 10(11)W/cm(2), with a corresponding energy density of ~100 J/cm(2).

Operation and output pulse characteristics of an extremely compact capillary-discharge tabletop soft-x-ray laser

We report on the operating parameters and laser output pulse characteristics of an extremely compact discharge-pumped 46.9-nm laser of a size comparable with that of many widely utilized visible and ultraviolet gas lasers. This capillary-discharge laser generated subnanosecond laser pulses with energies of as much as 25microJ by single-pass amplification in an 18.6-cm-long argon-plasma column. Measurements of the laser output energy, pulse width, far-field beam profile, and beam divergence are reported.

Determination of XUV optical constants by reflectometry using a high-repetition rate 46.9-nm laser

We report the measurement of the optical constants of Si, GaP, InP, GaAs, GaAsP, and Ir at a wavelength of 46.9 nm (26.5 eV). The optical constants were obtained from the measurement of the variation of the reflectivity as a function of angle utilizing, as an illumination source, a discharge pumped 46.9-nm table-top laser operated at a repetition rate of 1 Hz. These measurements constitute the first application of an ultrashort wavelength laser to materials research.

Extremely compact soft X-ray lasers based on capillary discharges

Extremely compact high repetition rate soft X-ray lasers based on capillary discharge excitation have demonstrated average powers of a few milliWatt at 46.9 nm, milli-Joule-level pulse energy, peak spectral brightness several orders of magnitude larger than third-generation synchrotron beam lines, and excellent spatial coherence. Examples of the use of a capillary discharge soft X-ray laser in dense plasma diagnostics and laser ablation of materials are summarized.

Coherence of VCSEL's for holographic interconnects

Temporal and spatial coherence measurements were conducted on the emission from AlGaAs-GaAs vertical-cavity surface-emitting lasers (VCSELs). Results of both CW and pulsed conditions from devices of 8- and 15-/spl mu/m diameter are reported. Coherence length of 0.6 mm for multi-mode and /spl sim/75 cm for single-mode were obtained. Thermal chirp reduces the single-mode coherence to 16 mm for 5 ns pulses. For holograms smaller than 0.6 mm in size the density of information that can be read by the VCSELs is diffraction-limited by the size of the holographic element.<<ETX>>

Lasing in Ne-like S and other new developments in capillary discharge ultrashort wavelength lasers

We report our most recent progress in the development of capillary discharge soft x-ray lasers. This includes the first observation of discharge-pumped ultrashort wavelength lasing in a material that is solid at room temperature (S), and preliminary results of discharges in Ca. Excitation by a capillary discharge of S vapor generated by discharge ablation of a solid target resulted in amplification in Ne-like S at 60.8 nm with a gain-length product of 7.5. Overheating of the electron temperature respect to steady-state ionization conditions and transient population effects significantly increased the gain above the steady state-value. The results of two-dimensional near-field and far-field imaging of a saturated table-top Ne-like Ar laser and the measurement of its spatial coherence as a function of amplifier length are also reported and compared with model calculations. The generation of a capillary discharge plasma waveguide is to be used in combination with ultrashort pulse laser excitation for the generation of a new kind of efficient collisional soft x- ray laser is discussed.

Capillary discharge tabletop soft X-ray lasers reach new wavelengths and applications

Abstract For many years, researchers have envisioned the development of compact high repetition rate tabletop soft X-ray lasers that could be routinely used in application in numerous disciplines. With demonstrated average powers of several mW and mJ-level pulse energy at 46.9 nm, capillary discharge-pumped lasers are the first compact lasers to reach this goal. In this paper we summarize the development status of high repetition rate tabletop soft X-ray lasers based on capillary discharge excitation, and give examples of their successful use in several applications. Results of the use of a capillary discharge pumped 46.9 nm laser in dense plasma interferometry, soft X-ray reflectometry for the determination of optical constants, and laser ablation are described. The observation of lasing at 53 nm line in Ne-like Cl with output pulse energy up to 10 μ J is also reported.

Spatially coherent tabletop soft X-ray laser sources with milliwatt average power

We summarize the development status of milliwatt average power tabletop soft X-ray lasers based on fast capillary discharges with essentially full spatial coherence, and give examples of their use in dense plasma interferometry, soft X-ray reflectometry, laser ablation, and plasma generation.

Advances in compact discharge-pumped soft X-ray lasers and applications

Summary form only given. For many years researchers have envisioned the development of compact high repetition rate soft lasers with high spatial coherence that be routinely used in numerous applications. With demonstrated average powers of several mW and millijoule-level pulse energy at 46.9 nm the Ne-like Ar capillary discharge-pumped laser is the first compact laser to reach this goal. We summarize the development status of tabletop soft X-ray lasers based on capillary discharge excitation, and give examples of their successful use in dense plasma interferometry, soft X-ray reflectometry for the determination of optical constants, characterization of diffraction gratings, laser ablation of materials, and plasma generation. Lasing at 52.9 nm line in Ne-like Cl, and the prospects for lasing at shorter wavelengths are also discussed.