Characteristics of extreme ultraviolet emission from mid-infrared laser-produced rare-earth Gd plasmas.

We characterize extreme ultraviolet (EUV) emission from mid-infrared (mid-IR) laser-produced plasmas (LPPs) of the rare-earth element Gd. The energy conversion efficiency (CE) and the spectral purity in the mid-IR LPPs at λL = 10.6 µm were higher than for solid-state LPPs at λL = 1.06 µm, because the plasma produced is optically thin due to the lower critical density, resulting in a CE of 0.7%. The peak wavelength remained fixed at 6.76 nm for all laser intensities studied. Plasma parameters at a mid-IR laser intensity of 1.3×10(11) W/cm(2) was also evaluated by use of the hydrodynamic simulation code to produce the EUV emission at 6.76 nm.

Synchrotron-radiation-stimulated etching of polydimethylsiloxane using XeF(2) as a reaction gas.

The synchrotron radiation (SR) stimulated etching of silicon elastomer polydimethylsiloxane (PDMS) using XeF(2) as an etching gas has been demonstrated. An etching system with differential pumps and two parabolic focusing mirrors was constructed to perform the etching. The PDMS was found to be effectively etched by the SR irradiation under the XeF(2) gas flow, and the etching process was area-selective and anisotropic. An extremely high etching rate of 40-50 microm (10 min)(-1) was easily obtained at an XeF(2) gas pressure of 0.2-0.4 torr. This suggests that SR etching using XeF(2) gas provides a new microfabrication technology for thick PDMS membranes, which can open new applications such as the formation of three-dimensional microfluidic circuits.

Evaluation of a flat-field grazing incidence spectrometer for highly charged ion plasma emission in soft x-ray spectral region from 1 to 10 nm.

A flat-field grazing incidence spectrometer operating on the spectral region from 1 to 10 nm was built for research on physics of high temperature and high energy density plasmas. It consists of a flat-field grating with 2400 lines/mm as a dispersing element and an x-ray charged coupled device (CCD) camera as the detector. The diffraction efficiency of the grating and the sensitivity of the CCD camera were directly measured by use of synchrotron radiation at the BL-11D beamline of the Photon Factory (PF). The influence of contamination to the spectrometer also was characterized. This result enables us to evaluate the absolute number of photons in a wide range wavelength between 1 and 10 nm within an acquisition. We obtained absolutely calibrated spectra from highly charged ion plasmas of Gd, from which a maximum energy conversion efficiency of 0.26% was observed at a Nd:YAG laser intensity of 3 × 1012 W/cm2.