Broadband THz Spectroscopy of Single Nanoscale Objects

Broadband terahertz (around 10 THz) generation and detection at 10 nm scales has recently been demonstrated\footnote{Y. Ma, \textit{et al.}, Nano Lett. \textbf{13}, 2884 (2013)} using LaAlO$_{3}$/SrTiO$_{3}$ nanostructures created by conductive atomic force microscope lithography.\footnote{C. Cen, \textit{et al.}, Nat. Mater. \textbf{7}, 298 (2008)} This unprecedented control of terahertz emission, on a scale four orders of magnitude smaller than the diffraction limit, provides a useful technique to investigate a variety of nanoscale objects. Here we report initial efforts to apply THz spectroscopy to a variety of objects whose dimensions are comparable to our spatial resolution. Systems under investigation include semiconductor quantum dots, Au nanorods and single molecules.