
136 Biosensors Based on Nanomaterials and Nanodevices
same system congurations, there are still many different ways of near-eld excitation and
detection. Figure 6.14 illustrates three possible methods usually used in characterization
experiments, and they are neareld illumination far-eld collection, far-eld illumination
neareld collection as well as neareld illumination neareld collection. The far-eld illu-
mination neareld collection method is most close to the real situation in the common
far-eld SERS spectroscopy. In this case, the focused laser light will excite a sample device
from far-eld but the scattering light will be only ...