Colloidal quantum dots

Light interaction with matter on a single quanta level is a process that in principle can be used for construction of gates for quantum computation. Semiconductor Quantum Dots (QD) are one of the good candidates to be applied for such a task. Quantized levels of a single QD permits it to serve as a single photon source and relatively high nonlinearity of these objects can allow efficient interaction of two (and more) photons, leading possibly to their entanglement.

Experimental facilities

In our experiments we are able to prepare and optically address a single QD in a confocal microscope, and investigate their spectral emission properties as well as the quantum statistics of the scattered light.

confocal microscope setup

Single quantum dots

The crucial question is to be able to stabilize a single QD at a room temperature. A stable quantum dot in a transparent matrix can serve in a first step as a single photon source, with an ability to tune the emission wavelength by engineering the size of the dots.

A signature of a identification of both a single quantum dot and a nonclassical light emission behavior is obtained from the photon statistics observed in a Hanbury-Brown - Twiss experiment, where we clearly observe photon antibunching in a CdSe/ZnS core-shell dot:

Photon antibunching signature