SPM head

As previously discussed, transmission mode is applicable only to thin/ nanomaterials or transparent samples even though the detection efficiency is very high owing to the capability of high NA objective lens. In order to apply tip enhancement to opaque or bulk samples such as silicon-based materials, reflection mode TERS has been developed [26, 86-90]. The idea of the reflection mode is very simple in a way that both illumination and detection are conducted at the same side of the tip and the samples surface as illustrated in Fig. 16.4b. The illumination can be either normal or oblique to the sample surface. Illumination depends on the availability of the space between objective lens and the SPM head. This critical issue is often solved using a relatively low NA objective lens with a long working... 

Fig. 3.7. MultiMode SPM head and major components laser (/) mirror (2) cantilever (3) tilt mirror (4) and photodetector (5). Reprinted from [9,13]...

---