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Edison, NJ, United States

Tuschel D.,HORIBA Scientific Inc.
Spectroscopy (Santa Monica) | Year: 2015

External vibrational modes or lowenergy phonons are very sensitive to crystal structure. Here, the author demonstrates the practicality of imaging lowenergy phonons to characterize 2D crystals and provides some cautions to keep in mind. Source

Tuschel D.,HORIBA Scientific Inc.
Spectroscopy (Santa Monica) | Year: 2012

Polarization/orientation (P/O) micro-Raman spectroscopy can be used to identify vibrational modes, determine crystal structure, distinguish allotropes and polymorphs, differentiate single from polycrystalline materials, and determine orientation of the crystal and degree of disorder, all on a micrometer scale. P/O micro-Raman spectroscopy promises to be an important analytical tool because of its complementarity to micro-X-ray diffraction. Here, we explain the theoretical basis for P/O micro-Raman spectroscopy and provide an example to demonstrate its feasibility. Source

Kamma I.,Alabama A&M University | Mbila M.,Alabama A&M University | Gall K.E.S.,HORIBA Scientific Inc. | Reddy B.R.,Alabama A&M University
Optical Materials Express | Year: 2013

Erbium doped oxyfluoride glass was synthesized from the molar composition 10.1% Na2CO3 -20.2% PbO -33.7% GeO2 -33.6% TeO2 -2.4% ErF3 by melt quenching technique. The Judd-Ofelt intensity parameters were estimated as Ω2 = 10.8 × 10-20, Ω4 = 1.17 × 10-20, and Ω6 = 4.32 × 10-20 cm2. Radiative transition probabilities and lifetimes were also calculated. Differential scanning calorimetry (DSC) was used for thermal analysis of the sample. Nanocrystals were induced in the glass by heattreatment. Strong room temperature upconversion emissions were observed at 415, 540, 554 and 667 nm from Er3+ doped sample under 972 nm Tisapphire laser excitation. X-ray diffraction (XRD) measurements revealed the presence of NaErF4 crystallites 35 nm in the glassy matrix. The concentration of nanocrystals is found to be low in the middle of the sample and higher close to the surface. Time correlated single photon counting (TCSPC) was used to measure Er3+ lifetimes. © 2013 Optical Society of America. Source

Garcia-Caurel E.,Ecole Polytechnique - Palaiseau | De Martino A.,Ecole Polytechnique - Palaiseau | Gaston J.-P.,HORIBA Jobin Yvon S.A.S. | Yan L.,HORIBA Scientific Inc.
Applied Spectroscopy | Year: 2013

This article provides a brief overview of both established and novel ellipsometry techniques, as well as their applications. Ellipsometry is an indirect optical technique, in that information about the physical properties of a sample is obtained through modeling analysis. Standard ellipsometry is typically used to characterize optically isotropic bulk and/or layered materials. More advanced techniques such as Mueller ellipsometry, also known as polarimetry in the literature, are necessary for the complete and accurate characterization of anisotropic and/or depolarizing samples that occur in many instances, both in research and in real-life activities. In this article, we cover three main subject areas: Basic theory of polarization, standard ellipsometry, and Mueller ellipsometry. The first section is devoted to a short, pedagogical introduction of the formalisms used to describe light polarization. The second section is devoted to standard ellipsometry. The focus is on the experimental aspects, including both pros and cons of commercially available instruments. The third section is devoted to recent advances in Mueller ellipsometry. Application examples are provided in the second and third sections to illustrate how each technique works. Source

Tuschel D.,HORIBA Scientific Inc.
Spectroscopy (Santa Monica) | Year: 2016

Were it not for the problem of photoluminescence, only one laser excitation wavelength would be necessary to perform Raman spectroscopy. Here, we examine the problem of photoluminescence from the material being analyzed and the substrate on which it is supported. We describe how to select an excitation wavelength that does not generate photoluminescence, reduces the noise level, and yields a Raman spectrum with a superior signal-to-noise ratio. Furthermore, we discuss the phenomenon of resonance Raman spectroscopy and the effect that laser excitation wavelength has on the Raman spectrum. Source

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