The kick-off of a large-scale European network
for research in 'Thermodynamics in the Quantum Regime' was celebrated
in Brussels on Tues 30 April 2013. The successful proposal for one of the prestigious COST
network grants, funded by the ESF, was led by UCL's researcher Dr Janet Anders.
Published: May 1, 2013 9:58:55 AM
In a recent STFC newsletter, UK news from CERN, Dr Stephen Hogan describes how he, and a team of international collaborators are investigating the properties of antimatter. The AEGIS experiment at the Antiproton Decelerator, in CERN has been designed to exploit techniques Stephen developed to accelerate antihydrogen atoms in excited states; to transport them and make beams suitable for measurements of the acceleration of antimatter in the Earth's gravitational field. More...
Published: Feb 14, 2013 12:14:34 PM
According to Wannier's law, when a single
photon is absorbed with energy just above the fragmentation threshold, the
electrons in a multi-electron atom break-up in the most symmetric way.
Published: Feb 11, 2013 3:47:22 PM
Biological Physics and Optical Tweezers
We have a program of research aimed at applying optical physics techniques to biological and life sciences questions.
Optical tweezers (Dr Phil Jones)
Optical tweezers are a useful and important tool with many applications in the physical and life sciences. By strongly focussing a laser beam we can trap and manipulate microscopic objects at the beam waist. We are using optical tweezers for trapping a variety of objects interesting for life sciences or soft matter, including microscopic bubbles and carbon nanotubes.
More information about this research is on the optical tweezers website.
Ultrafast laser spectroscopy of biological systems (Dr Angus Bain)
Dr Angus Bain's group works on the development and application of ultrafast lasers - lasers that produce pulses of light as short as a few femtoseconds (1 femtosecond is 10-15 s).In the picture on the left you can see the sum frequency generator which combines laser light at two different wavelengths (colours) to produce light at a third wavelength. The output of this is the red light in the middle of the picture, which is pulsing at a rate of 250,000 times per second, each pulse being just 200 fs long.
The aim of the Bain group's work
is to use the very short pulses of laser light to measure the
orientation and very fast rotation of molecules ('probes') when they
are placed in an environment that restricts their motion.
The probe is a chromophore, a molecule that absorbs light of one colour and re-emits is at a different one. By analysing the light emitted by the chromophore, particularly its polarisation, we can obtain information about the way the molecule is moving ('tumbling' and 'wobbling' motion), and so deduce the nature of the environment surrounding it.
Highly ordered molecular environments can commonly be found in the biological sciences, for example in cell membranes. In particular this method can be used to detect and measure changes in the biological environment from the changes they cause to the motion of the probe molecules.