Instrumentation for optics at the nanoscale
Luiz H. G. Tizei
Optical spectroscopy is traditionally performed in a confocal optical microscope, allowing spatial resolution of the order of a few hundred nanometers (the resolution is better for super-resolution techniques). However, for many applications, knowledge about an object emission spectrum at lower scales is necessary. A possible solution is to use a finer probe, such a focused fast electron beam or a fine metallic tip to excite the object.
In this seminar, we will first describe the necessary instrumentation to perform cathodoluminescence in a scanning transmission electron microscope (nano-CL). This setup allows experiments with an ultimate spatial resolution limited by the sample being observed. As examples, we will describe two applications: 1) the confined quantum Stark effect inGaN quantum disks in AlN nanowires and 2) two-color cell marking using nanodiamonds.
The nano-CL system can also be used to measure the light emission statistics of the object under electron irradiation, if it is coupled to a light intensity interferometer. We will describe the interferometer construction and its use to detect single photon sources and to measure emitters’ lifetimes. Finally, we will apply this later capability to measure the coupling between neutral nitrogen-vacancy centers in nanodiamonds and silver nanocubes through the Smith-Purcell effect.