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10VORTEX BEAM-BASED RAMAN SPECTROSCOPY FOR CELL MEMBRANE STUDIES
GHANASHYAM C, ASEEFHALI BANKAPUR*, SANTHOSH CHIDANGIL
Department of Atomic and Molecular Physics, Manipal Academy of Higher Education, Manipal-576104, India
asifbankapur@manipal. edu
ABSTRACT
Spiral phase plate (SPP) is an optical element with an optical thickness that varies with azimuthal angle so that the incident beam arises with a spiral phase front. Thus, a Gaussian beam incident on SPP emerges out as a vortex beam having a central null region with doughnut shape intensity distribution. Herein we mainly concentrate on initial result obtained when an SPP is introduced into a micro-Raman setup. Beam profiling of the vortex beam was done at focus of a biconvex lens and compared with the Gaussian beam profile obtained at the same point. Images of the vortex beam were taken at the focus of the microscope objectives using the NIS-D elements software. The inner and outer diameter was measured to choose the appropriate sample for our studies. Raman spectrum of Tylenol was obtained using vortex beam and found that vortex beam was able to reproduce all the peaks recorded using the Gaussian beam. A dye-polystyrene system was prepared, and experiments were performed to show that using vortex beam Raman signals can be obtained exclusively from the boundaries.
Keywords: Spiral Phase Plate, Vortex beam, Raman spectrum, Dye-polystyrene system
