Correlated measurements of plasmon resonance Rayleigh scattering and surface-enhanced resonance Raman scattering using a dark-field microspectroscopic system

The current work demonstrates development of a dark-field microspectroscopic system by combining Rayleigh scattering spectroscopy and surface-enhanced resonance Raman scattering (SERRS) spectroscopy on an optical microscope. The microspectroscopic system was helpful for identifying plasmon resonance Rayleigh scattering from isolated Ag nanoaggregates and simultaneous measurements of SERRS signals from the nanoaggregates. Furthermore, the use of a microspectroscopic system for correlated measurements of plasmon resonance Rayleigh scattering and SERRS signals enabled us to establish relationships between SERRS, excitation polarization, excitation energy, and plasmon resonance energy. The relationships between SERRS, excitation polarization, excitation energy, and plasmon resonance energy allowed us not only to identify optimum excitation condition for maximum SERRS but also clarification of a mechanism underlying SERRS. Details of microspectroscopic system, measurement of plasmon resonance Rayleigh scattering and SERRS, and a mechanism of SERRS are discussed.