@article{hallen_ayars_jahncke_2003, place={UK}, title={The effects of probe boundary conditions and propagation on nano-Raman spectroscopy}, volume={210}, ISSN={["0022-2720"]}, url={http://dx.doi.org/10.1046/j.1365-2818.2003.01138.x}, DOI={10.1046/j.1365-2818.2003.01138.x}, abstractNote={Summary}, number={3}, journal={JOURNAL OF MICROSCOPY-OXFORD}, author={Hallen, HD and Ayars, EJ and Jahncke, CL}, year={2003}, month={Jun}, pages={252–254} }
 @article{ayars_jahncke_paesler_hallen_2001, place={UK}, title={Fundamental differences between micro- and nano-Raman spectroscopy}, volume={202}, ISSN={["0022-2720"]}, url={http://dx.doi.org/10.1046/j.1365-2818.2001.00878.x}, DOI={10.1046/j.1365-2818.2001.00878.x}, abstractNote={Electric field polarization orientations and gradients close to near‐field scanning optical microscope (NSOM) probes render nano‐Raman fundamentally different from micro‐Raman spectroscopy. With x‐polarized light incident through an NSOM aperture, transmitted light has x, y and z components allowing nano‐Raman investigators to probe a variety of polarization configurations. In addition, the strong field gradients in the near‐field of a NSOM probe lead to a breakdown of the assumption of micro‐Raman spectroscopy that the field is constant over molecular dimensions. Thus, for nano‐Raman spectroscopy with an NSOM, selection rules allow for the detection of active modes with intensity dependent on the field gradient. These modes can have similar activity as infra‐red absorption modes. The mechanism can also explain the origin and intensity of some Raman modes observed in surface enhanced Raman spectroscopy.}, number={1}, journal={JOURNAL OF MICROSCOPY-OXFORD}, author={Ayars, EJ and Jahncke, CL and Paesler, MA and Hallen, HD}, year={2001}, month={Apr}, pages={142–147} }
 @article{ayars_hallen_jahncke_2000, title={Electric field gradient effects in Raman spectroscopy}, volume={85}, ISSN={["0031-9007"]}, url={http://dx.doi.org/10.1103/PhysRevLett.85.4180}, DOI={10.1103/PhysRevLett.85.4180}, abstractNote={Raman spectra of materials subject to strong electric field gradients, such as those present near a metal surface, can show significantly altered selection rules. We describe a new mechanism by which the field gradients can produce Raman-like lines. We develop a theoretical model for this "gradient-field Raman" effect, discuss selection rules, and compare to other mechanisms that produce Raman-like lines in the presence of strong field gradients. The mechanism can explain the origin and intensity of some Raman modes observed in SERS and through a near-field optical microscope (NSOM-Raman).}, number={19}, journal={PHYSICAL REVIEW LETTERS}, author={Ayars, EJ and Hallen, HD and Jahncke, CL}, year={2000}, month={Nov}, pages={4180–4183} }
 @inbook{ayars_paesler_hallen_2000, title={Near-field Raman spectroscopy: electric field gradient effects}, volume={165}, ISBN={0750306858}, number={2000}, booktitle={Microbeam Analysis 2000: proceedings of the Second Conference of the International Union of Microbeam Analysis Societies held in Kailua-Kona, Hawaii, 9-14 July 2000}, publisher={Bristol: Institute of Physics Publishing}, author={Ayars, E. J. and Paesler, M. A. and Hallen, H. D.}, editor={Williams, D. B. and Shimizu, R.Editors}, year={2000}, pages={115–116} }
 @article{ayars_hallen_2000, title={Surface enhancement in near-field Raman spectroscopy}, volume={76}, ISSN={["0003-6951"]}, url={http://dx.doi.org/10.1063/1.126818}, DOI={10.1063/1.126818}, abstractNote={The intensity and selection rules of Raman spectra change as a metal surface approaches the sample. We study the distance dependence of the new Raman modes with a near-field scanning optical microscope (NSOM). The metal-coated NSOM probe provides localized illumination of a metal surface with good distance control. Spectra are measured as the probe approaches the surface, and the changes elucidated with difference spectra. Comparisons to a theoretical model for Raman excitation by evanescent light near the probe tip indicate that while the general trends are well described, the data show oscillations about the model.}, number={26}, journal={APPLIED PHYSICS LETTERS}, author={Ayars, EJ and Hallen, HD}, year={2000}, month={Jun}, pages={3911–3913} }
 @article{ayars_aspnes_moyer_paesler_1999, title={Proximal electromagnetic shear forces}, volume={196}, DOI={10.1046/j.1365-2818.1999.00596.x}, abstractNote={We perform a simple model calculation to estimate the electromagnetically induced shear force caused by a current dissipation when a charged tip is moved parallel to a conducting material. For parameters typical in shear force imaging, the force is many orders of magnitude below reported values. Thus, proximal electromagnetic tip–sample forces can be neglected in discussions of shear force imaging.}, number={1}, journal={Journal of Microscopy}, author={Ayars, E. and Aspnes, D. E. and Moyer, P. and Paesler, M. A.}, year={1999}, pages={59–60} }