Dual Raman-Brillouin Microscope for Chemical and Mechanical Characterization and Imaging.

We present a unique confocal microscope capable of measuring the Raman and Brillouin spectra simultaneously from a single spatial location. Raman and Brillouin scattering offer complementary information about a material's chemical and mechanical structure, respectively, and concurrent monitoring of both of these spectra would set a new standard for material characterization. We achieve this by applying recent innovations in Brillouin spectroscopy that reduce the necessary acquisition times to durations comparable to conventional Raman spectroscopy while attaining a high level of spectral accuracy. To demonstrate the potential of the system, we map the Raman and Brillouin spectra of a molded poly(ethylene glycol) diacrylate (PEGDA) hydrogel sample in cyclohexane to create two-dimensional images with high contrast at microscale resolutions. This powerful tool has the potential for very diverse analytical applications in basic science, industry, and medicine.

[1]  Carl Paterson,et al.  Spectral broadening in Brillouin imaging , 2013 .

[2]  N Stone,et al.  Mechanical mapping with chemical specificity by confocal Brillouin and Raman microscopy. , 2014, The Analyst.

[3]  Vladislav V. Yakovlev,et al.  Optimizing signal collection efficiency of the VIPA-based Brillouin spectrometer , 2015 .

[4]  Giuliano Scarcelli,et al.  Brillouin microscopy of collagen crosslinking: noncontact depth-dependent analysis of corneal elastic modulus. , 2013, Investigative ophthalmology & visual science.

[5]  Kyle C. Doty,et al.  Raman spectroscopy of blood for species identification. , 2014, Analytical chemistry.

[6]  S. Yun,et al.  Multistage VIPA etalons for high-extinction parallel Brillouin spectroscopy , 2011, Optics express.

[7]  Vladislav V. Yakovlev,et al.  Background clean-up in Brillouin microspectroscopy of scattering medium. , 2014, Optics express.

[8]  H. Hamaguchi,et al.  Fast Low Frequency (Down to 10 cm−1) Multichannel Raman Spectroscopy Using an Iodine Vapor Filter , 2009, Applied spectroscopy.

[9]  William B. White,et al.  Characterization of diamond films by Raman spectroscopy , 1989 .

[10]  J. Randall,et al.  Brillouin scattering, density and elastic properties of the lens and cornea of the eye , 1980, Nature.

[11]  William F. Finney,et al.  Subsurface Probing in Diffusely Scattering Media Using Spatially Offset Raman Spectroscopy , 2005, Applied spectroscopy.

[12]  Vladislav V. Yakovlev,et al.  Comparison of coherent and spontaneous Raman microspectroscopies for noninvasive detection of single bacterial endospores , 2007, Proceedings of the National Academy of Sciences.

[13]  M. M. Piñeiro,et al.  Density, speed of sound and refractive index of (n-hexane + cyclohexane + 1-hexanol) atT = 298.15 K☆ , 2001 .

[14]  A. Yalin,et al.  Characterization of laser seeding by use of group-velocity dispersion in an atomic-vapor filter. , 2000, Optics letters.

[15]  Zhaokai Meng,et al.  Brillouin spectroscopy as a new method of screening for increased CSF total protein during bacterial meningitis , 2015, Journal of biophotonics.

[16]  Michael S Feld,et al.  Turbidity-corrected Raman spectroscopy for blood analyte detection. , 2009, Analytical chemistry.

[17]  S Lees,et al.  Studies of compact hard tissues and collagen by means of Brillouin light scattering. , 1990, Connective tissue research.

[18]  M. Dresselhaus,et al.  Perspectives on carbon nanotubes and graphene Raman spectroscopy. , 2010, Nano letters.

[19]  Chandrasekhar Roychoudhuri.  Demonstrations using a Fabry–Perot. I. Multiple‐slit interference , 1975 .

[20]  S. Yun,et al.  Confocal Brillouin microscopy for three-dimensional mechanical imaging. , 2007, Nature photonics.

[21]  M. Shirasaki.  Large angular dispersion by a virtually imaged phased array and its application to a wavelength demultiplexer. , 1996, Optics letters.

[22]  G. M. Hale,et al.  Optical Constants of Water in the 200-nm to 200-microm Wavelength Region. , 1973, Applied optics.

[23]  J. B. Simeonsson,et al.  Raman spectrometry with metal vapor filters. , 1992, Analytical chemistry.

[24]  B. Hillebrands,et al.  Construction and performance of a Brillouin scattering set-up using a triple-pass tandem Fabry-Perot interferometer , 1987 .

[25]  V. A. D. Grosso,et al.  Speed of Sound in Pure Water , 1972 .

[26]  M. Thewalt,et al.  Fourier Transform Raman and Brillouin Spectroscopy Using Atomic Vapor Filters , 1994 .

[27]  Silvia Caponi,et al.  Biomechanics of fibrous proteins of the extracellular matrix studied by Brillouin scattering , 2014, Journal of The Royal Society Interface.

[28]  H. Mao,et al.  Elasticity of MgO and a primary pressure scale to 55 GPa. , 2000, Proceedings of the National Academy of Sciences of the United States of America.

[29]  Zachary D. Schultz,et al.  Advances in biomedical Raman microscopy. , 2014, Analytical chemistry.

[30]  J. White,et al.  Phonons and the elastic moduli of collagen and muscle , 1977, Nature.