A couple of current excerpts from Nature which may be of interest:

Nature 414, 509 - 513 (2001) © Macmillan Publishers Ltd.
 
 

Attosecond metrology

M. HENTSCHEL*Ý, R. KIENBERGER*Ý, CH. SPIELMANN*, G. A. REIDER*, N. MILOSEVIC*, T. BRABEC*, P. CORKUMý,
U. HEINZMANN§, M. DRESCHER§ & F. KRAUSZ*

* Institut für Photonik, Technische Universität Wien, Gusshausstr. 27, A-1040 Wien, Austria
ý Steacie Institute of Molecular Sciences, NRC Canada, Ottawa, Canada K1A 0R6
§ Fakultät für Physik, Universität Bielefeld, D-33615 Bielefeld, Germany
Ý These authors contributed equally to this work

Correspondence and requests for materials should be addressed to F.K. (e-mail: ferenc.krausz@tuwien.ac.at).
 

The generation of ultrashort pulses is a key to exploring the dynamic behaviour of matter on ever-shorter
timescales. Recent developments have pushed the duration of laser pulses close to its natural limit—the
wave cycle, which lasts somewhat longer than one femtosecond (1 fs = 10-15 s) in the visible spectral
range. Time-resolved measurements with these pulses are able to trace dynamics of molecular structure,
but fail to capture electronic processes occurring on an attosecond (1 as = 10-18 s) timescale. Here we trace
electronic dynamics with a time resolution of  150 as by using a subfemtosecond soft-X-ray pulse and a
few-cycle visible light pulse. Our measurement indicates an attosecond response of the atomic system, a
soft-X-ray pulse duration of 650  150 as and an attosecond synchronism of the soft-X-ray pulse with the
light field. The demonstrated experimental tools and techniques open the door to attosecond spectroscopy
of bound electrons.

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Nanotechnology: Synthesis of carbon 'onions' in water

N. SANO*Ý, H. WANG*, M. CHHOWALLA*, I. ALEXANDROU* & G. A. J. AMARATUNGA*

* Department of Engineering, University of Cambridge, Trumpington Street, Cambridge CB2 1PZ, UK
Ý Present address: Department of Chemical Engineering, Himeji Institute of Technology, Himeji 671-2201, Japan

e-mail: mc209@eng.cam.ac.uk
 

The fabrication of carbon nanomaterials usually calls for expensive vacuum systems to generate plasmas
and yields are disappointingly low. Here we describe a simple method for producing high-quality spherical
carbon nano-'onions' in large quantities without the use of vacuum equipment. The nanoparticles, which
have C60 cores surrounded by onion-like nested particles, are generated by an arc discharge between two
graphite electrodes submerged in water. This technique is economical and environmentally benign, and
produces uncontaminated nanoparticles which may be useful in many applications.

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