Vacuum Ultraviolet Lasers

ATR-far-ultraviolet spectroscopy: a challenge to new σ chemistry

“…FUV spectroscopy of the gas phase has a long history. 1,2,4,7–11 Many gas molecules with sufficient vapor pressure were subjected to FUV measurement. Fig.…”

“…The UV region above 190 nm is extremely rich in information about electronic structures and transitions, but absorbance in this region is so strong that this region has been used mainly for studying the electronic structures and transitions of gas molecules. 7–11 Since particles in the condensed phase do not transmit light in the FUV region, reflection spectroscopy was employed to measure spectra of solid samples above 190 nm. 7–10 However, for liquid samples, it is difficult to use both absorption spectroscopy and reflection spectroscopy.…”

“…7–11 Since particles in the condensed phase do not transmit light in the FUV region, reflection spectroscopy was employed to measure spectra of solid samples above 190 nm. 7–10 However, for liquid samples, it is difficult to use both absorption spectroscopy and reflection spectroscopy. To overcome the above difficulties of UV spectroscopy above 190 nm in spectral measurements, we introduced attenuated total reflection (ATR) technique to the FUV region that allows us to measure spectra for almost all kinds of molecules in the 145–280 nm region.…”

New phase-matching selection rule to generate angularly isolated harmonics

“…Conventionally, nonlinear media are employed to transform the fundamental frequency of the input laser to those of high harmonics to obtain extreme ultraviolet and even X-ray beams using table-top lasers [1,2] . High harmonic generation (HHG), as an ideal tool, can be applied in probing electronic dynamics on the atomic or molecular scale, microscale imaging, etc.…”

“…This chain selection rule is demonstrated by the phase-matching schemes (a) and (b). W/cm 2 , and the crossing angle is small enough to ensure adequate interaction.…”