Optical trapping of porous silicon nanoparticles

Our paper Optical trapping of proous silicon nanoparticles has now been published as M. G. Donato et al, Nanotechnology 22 505704 (2011).

Abstract: Silicon nanoparticles obtained by ball-milling of a 50% porosity silicon layer have been optically trapped when dispersed in a water–surfactant environment. We measured the optical force constants using linearly and radially polarized trapping beams finding a reshaping of the optical potential and an enhanced axial spring constant for the latter. These measurements open perspectives for the control and handling of silicon nanoparticles as labeling agents in biological analysis and fluorescence imaging techniques.

Harrie Massey Lecture

Prof Niek van Hulst (ICFO Barcelona) is visiting the UCL Physics Department today and giving the annual Harrie Massey Lecture on the topic of Coherent control of single molecules, complexes and nanoantennae.

Abstract: The observation of quantum mechanical effects in biological systems, such as light-harvesting antennae, has opened a lively debate as to the role of coherences in natural systems. Traditionally, such coherences are probed by manipulating quantum interference effects with shaped laser pulses. Yet the intrinsic structural inhomogeneity and environmental fluctuations of complex systems at ambient conditions average out most oscillatory spectroscopic features. Only by “single molecule detection” one can hope to catch a glimpse through the disorder. This lecture will present coherent control of single molecules, allowing both observation and manipulation of vibrational wave-packet interference and Rabi-oscillations in individual molecules at ambient conditions. The single-molecule approach ensures that the ultimate degree of coherent control can be realized. We have applied our novel method to single light-harvesting complexes and optical nanoantennas. Recent results on ultrafast quantum coherent energy transfer and femtosecond control of nanoscale hotspots will be presented.

Visit by Onofrio Marago and Maria Grazia Donato

This week (21-26 November) Onofrio Marago and Maria Grazia Donato from the NanoSoft Lab, IPCF-CNR (Messina) are visiting our group at UCL.  Our groups have a long-running collaboration, and exchange visits are funded by the Royal Society as part of our International Joint Project on Photonic Force Microscopy.

Microbubble User Group Meeting

The latest Microbubble User Group (microBUG) meeting is being held on Wed 16 November at Imperial College.  The programme of talks for the day is:

David (single bubble characterisation)
Susan (optical trapping of bubbles)
Terence (acousto-optic bubble characterisation)
Virginie (bubble formation in decompression sickness)
Jonathan (charactertization of adherent microbubbles)
Grace (stability of gold coated bubbles)
IEEE meeting highlights

The meetings are held in the Royal School of Mines, and hosted by Mengxing Tang.

Visit to NanoSoft Lab, IPCF-CNR (Messina)

Phil is spending the week of 07-11 November visiting Onofrio Marago and colleagues at the NanoSoft Lab, IPCF-CNR (Messina).  Our groups have a long-running collaboration, and exchange visits are funded by the Royal Society as part of our International Joint Project on Photonic Force Microscopy.