Fabrication of Fluorescent Nanoprobes and Their Applications in Nanophotonics

In recent years, nanoprobe-based devices have attracted significant attention and found a wide range of applications, including nanostructure imaging, single molecular detection, and physical, chemical, and biological sensing applications. However, since the scale of nanodevices is substantially less than the optical diffraction limit, their fabrication remains a difficult challenge. Despite significant efforts, most of the fabrication techniques developed so far require expensive equipment and complicated processing procedures, which has hindered their applications.

In this thesis, we developed a new class of fluorescent nanoprobes consist of a silica fiber taper, a single carbon nanotube, and nanoscale fluorescent elements (such as semiconductor quantum dots). This nanoprobe provides a natural interface between the nanoscale structures (i.e., the fluorescent elements) and the microscale structure (i.e., the fiber taper), which can significantly simplify their fabrication. Furthermore, since the nanoscale fluorescent elements are produced through bottom-up processes such as chemical synthesis, we can easily tailor the functionalities of such fluorescent nanoprobes to many different applications in nanophotonics, including near field imaging, nonlinear optics mapping, and quantum electrodynamics.

We have custom designed an optical system for this nanoprobe fabrication. We have characterized the nanoprobes using transmission electron microscope (TEM) and scanning electron microscope (SEM) and performed preliminary experiments on near field scanning. Our current fabrication/imaging systems can be readily upgraded to achieve more advanced applications in nonlinear optics and quantum optics.