(Color online) Illustration of the Langmuir-Blodgett/substrate SERS model. The pump field , scattered by the substrate (gray region) surface, is driving the Raman-shifted emission from the LB film (red layer), which is in turn scattered by the substrate into the far field (detection).
Schematics of the scattering geometry.
(Color online) Square amplitude of the Raman Fresnel coefficients , from a Ag surface as a function of both the incident angle and the Raman emission wavelength, for a pump plane wave at [(a)–(c)] and at [(d)–(f)]. [(a) and (d)] , [(b) and (e)] , and [(c) and (f)] .
(Color online) Square amplitude of the normalized Raman Fresnel coefficients , from a Ag surface as a function of the incident angle for various Raman shifts. Solid curves: ; dashed curves: ; and dash-dotted curves . (a) Incident pump field of wavelength , (black), (red), and (blue). (b) Incident pump field of wavelength , (black), (red), and (blue).
(Color online) Near electric field intensity maps in a scale, from a rough Ag surface with and , for normal incidence and in an area of . (a) Pump field. [(b)–(d)] SERS field at (b) , (c) Stokes emission at , and (d) anti-Stokes emission at .
(Color online) (a) Angular dependence of the SERS scattered intensity at for a pump field normally incident at , from Ag rough surfaces with with (black curves), (red curves), and planar surfaces (blue curves), for a single realization (dashed curves) and averaged over 600 realizations (solid curves). (b) Angular dependence of the SERS scattered intensity for various angles of the incident pump field at : (blue curves), (red curves), and (black curves). Rough Ag surfaces with (thick curves) and a planar surface (thin curves) are considered: (solid curves), anti-Stokes emission with (dashed curves), and Stokes emission with (dash-dotted curves).
(Color online) Spectral dependence of the average SERS enhancement factors (averaged over 200 realizations) for rough silver surfaces as a function of the incident frequency (negligible Raman shift) from (a) our collective model and (b) the approximation (1): (circles), (squares), (red solid curves), (black dashed curves), and (blue dash-dotted curves). Inset: average SERS enhanced factors for fixed pump field at as a function of the frequency shift, calculated with our collective model (solid curves, filled symbols) and with the approximation (1) (dashed curves, hollow symbols), the latter rescaled by the shown factors: with (red circles), (black circles), and (blue squares).
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