Photothermal measurement of absorption and scattering losses in thin films excited by surface plasmons

ESTEBAN A. DOMENÉ; FRANCISCO BALZAROTTI; ANDREA V. BRAGAS; OSCAR E. MARTÍNEZ

OPTICS LETTERS

OPTICAL SOC AMER

Año: 2009 vol. 34 p. 3797 - 3799

0146-9592

<!-- /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman";} @page Section1 {size:612.0pt 792.0pt; margin:70.85pt 3.0cm 70.85pt 3.0cm; mso-header-margin:36.0pt; mso-footer-margin:36.0pt; mso-paper-source:0;} div.Section1 {page:Section1;} --> We present a novel non contact, photothermal technique, based on the focus error signal of a commercial CD pickup head, which allows direct determination of absorption in thin films. Combined with extinction methods, this technique yields the scattering contribution to the losses. Surface plasmon polaritons are excited using Kretschmann configuration in thin Au films of different thickness. By measuring the extinction and absorption simultaneously, it is shown that dielectric constants and thickness retrieval leads to inconsistencies if the model does not account for scattering