Construction, Optimization and Testing of a Coherent Anti-Stokes Raman Scattering Microscope
Year: 2011
Type: article
Abstract: Coherent anti-Stokes Raman scattering (CARS) microscopy is a nonlinear vibrational microscopy technique that generates an anti-Stokes signal that is used to detect the presence of chemical species based on their vibrational signature.This anti-Stokes signal is generated from the interaction of pump beam, Stokes beam and probe beam in a sample.CARS microscopy involves the combination of spectroscopy and microscopy that allows noninvasive characterization and imaging of chemical species without preparation or labeling.Three-dimensional sectioning with high sensitivity and resolution can be obtained from the contrast mechanism generated from the intrinsic molecular vibrational properties of the specimen.This work presents the building of a broadband CARS microscope set-up in the Allen laboratory.It will discuss in detail the steps that were taken for the set-up and proper alignment of the system.A femtosecond Ti:Sapphire laser is used as the laser source and is divided into arms to form the pump and the Stokes beam.A photonic crystal fiber is used to generate the broad supercontinuum of light for the Stokes beam that will interact with the narrowband pump beam to generate a CARS signal at the sample focus.For the initial generation of a CARS signal, a forward CARS signal detection set-up was explored to produce a stronger CARS signal from a sample of liquid hexadecane.After ensuring correct alignment, that is, spatial and temporal overlap of the iii two beams, a broad CARS signal was obtained for the CH 2 symmetric stretch.After generation of a forward CARS signal, the two beams are then sent to the microscope to generate an epi-CARS signal.At present, epi-detection is being set-up and optimized for the generation of an epi-CARS signal with a good spectral resolution and sensitivity.Dr. Heather Allen, for just simply believing in me and for providing the guidance, support and wisdom I need to finish this thesis and for always having time to bounce ideas off with.To Mr. John Carter of Newport Coporation, for always having time to answer my questions and for showing me patiently the techniques in building the instrument.To the members of the Allen group, in particular, Dr. Tang, Dr. Cheng, Dr. Sierra-Hernandez and Dr. Casillas-Ituarte, for their patience, encouragements and valuable insights that were instrumental to the success of this work.I would also like to thank Mr. Hardy Castada for always extending an extra set of hands or eyes when needed and for the encouragement and friendship that has kept my sanity throughout this work.To my Filipino Christian Fellowship family and friends for always including me in their prayers.To my family, for trusting and believing in me even if the task seems daunting.And above all, to Almighty God, for his grace and faithfulness, and to whom I give back all glory, honor and praise.vi
Author: Minette Ocampo
Institution: The Ohio State University
Language: English
Subfield: Biophysics
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W2599097570