ABSTRACT
Nano structured materials such as semiconducting or metallic quantum dots (QD) easily exhibit due to their size-dependent electronic wavefunctions tunable optical properties. This chapter focuses on the experimental principles of optical single-QD detection and those properties of single QDs which can be tuned across the interface to the nanoscopic environment. It shows that single-QD detection offers an exciting view on the “individuality” of quantum objects giving direct access in time and space to essential microscopically relevant spectroscopic properties than those explored via ensemble experiments for centuries. Naturally, ensemble experiments are a convolution of inhomogeneities among individual QDs and during observation of time-varying properties of a single QD. The majority of experiments are nowadays performed making use of a reduction of the detection volume which is doped with ultralow concentrations of QDs. Wide-field microscopy is used in case several tens to hundred QDs should be investigated simultaneously.
