Raman imaging of floating cells
Caitriona M. Creely, Giovanni Volpe, Gajendra P. Singh, Marta Soler & Dmitri Petrov
Optics Express 13(16), 6105–6110 (2005)
Raman imaging can yield spatially resolved biochemical information from living cells. To date there have been no Raman images published of cells in suspension because of the problem of immobilising them suitably to acquire space-resolved spectra. In this paper in order to overcome this problem the use of holographic optical tweezers is proposed and implemented, and data is shown for spatially resolved Raman spectroscopy of a live cell in suspension.
Real-time detection of hyperosmotic stress response in optically trapped single yeast cells using Raman microspectroscopy
Gajendra P. Singh, Caitriona M. Creely, Giovanni Volpe, Helga Grötsch & Dmitri Petrov
Analytical Chemistry 77(8), 2564–2568 (2005)
Living cells survive environmentally stressful conditions by initiating a stress response. We monitored changes in the Raman spectra of optically trapped Saccharomyces cerevisiae yeast cell under normal, heat-treated, and hyperosmotic stress conditions. It is shown that when glucose was used to exert hyperosmotic stress, two chemical substancesglycerol and ethanolcan be monitored in real time in a single cell.
Generation of cylindrical vector beams with few-mode fibers excited by Laguerre–Gaussian beams
Giovanni Volpe & Dmitri Petrov
Optics Communications 237(1), 89–95 (2004)
We propose a novel method to efficiently produce light beams with radial, azimuthal, and hybrid polarization, through a few-mode fiber excited by a Laguerre–Gaussian beam. With different input polarization we can selectively excite different combinations of modes from the LP11 group. We propose to show how to transform the output beam into a cylindrical vector beam in free-space through various polarization transformations.