Recent progress on attosecond science at RIKEN
We have been developing two types of intense attosecond beam lines for investigating attosecond wavepackt dynamics in atoms and molecules. One produces an attosecond pulse train for attosecond Fourier transform spectroscopy by attosecond-pump/attosecond-probe scheme, while the other produces an intense isolated attosecond pulse for attosecond nonlinear optics.
Carrier-envelope phase stabilization of a 16 TW, 10  Hz Ti:sapphire laser.
We propose and demonstrate a simple and promising method for stabilizing the carrier-envelope phase (CEP) of a high-energy ultrashort pulse laser operating at a low repetition rate. The method was successfully applied to a Ti:sapphire laser operating at 10 Hz with 400 mJ pulse energy and 25 fs pulse duration (16 TW). The laser system consists of a 1 kHz front-end preamplifier and a 10 Hz back-end power amplifier. By sampling a 500 Hz reference pulse from a 1 kHz seed pulse, the measured single-shot CEP noise of a 10 Hz amplified pulse is stabilized to 670 mrad rms. Our proposed CEP stabilization concept can be applied to single-shot ultrahigh-power lasers, such as a petawatt laser system.
Professor Penck's Bluff: Geography, Espionage and Hysteria in World War I
Abstract This article considers the image of geography during World War I through a discussion of newspaper controversies about the pre‐war activities of German and British geographers. Early in the war, Sven Hedin and Albrecht Penck, renowned geographers whose achievements had been widely celebrated by the British geographical establishment, were named in the media as enemy spies whose supposedly disinterested scientific inquiries in Britain and the Empire had masked their real intention to pass sensitive information to the German High Command. British geography stood accused of collusion with enemy ‘super spies’. This article examines how Britain's geographical community, represented by the Royal Geographical Society, sought to defend the discipline's patriotic virtue and head off a full‐scale media witch‐hunt. In so doing, the article comments on the media's role in shaping the image of geography and on geography's place in public debates about the sanctity of the national space.