Single photon sources

DBT molecules as versatile emitters

DBT-doped Anthracene Nanocrystals showing stable and narrow photoemission [1]
DBT-doped Anthracene Nanocrystals showing stable and narrow photoemission [1]
SEM image of WG + coupler + ring
SEM image of WG + coupler + ring

A growing demand of data exchange capacity and sensitive monitoring of quality, as well as of environmentally or health-relevant agents is driving scientific research. In this context, harnessing quantum effects at the individual particle level promises exponentially faster computing, fully secure communications and unparalleled sensing capabilities. Nowadays, photonic structures able to guide light propagation can be designed and engineered in order to efficiently collect the radiation of nearby-placed single emitters, and, thanks to the Purcell effect, it is in principle possible to enhance the coupling into a simple dielectric waveguide mode up to 50%.

Single Polyaromathic Hydrocarbons (PAHs) molecules in appropriate host systems coherently interact with light at low temperatures. Such interaction can be controlled at the single photon level when the emitters are efficiently coupled to nanophotonic devices. In such a system, single molecules can play both the role of single photon sources and nonlinear elements, so as to unprecedently enable on-chip single-photon logical gates.

SEM image of a sublimated anthracene crystal
SEM image of a sublimated anthracene crystal
Fluorescence widefield image @ 4K while varying excitation frequency.
Fluorescence widefield image @ 4K while varying excitation frequency.

We investigate a simple device consisting of single emitters (Dibenzoterrylene molecules (DBT) hosted in anthracene crystals) placed very close (tens of nanometers) to dielectric waveguides. Due to outstanding photostability, strong dipole transitions in the near-infrared (780 nm), lifetime- limited linewidth of 30 MHz at 3 K temperature and easy manipulation of the thin host matrix, individual DBT molecules are ideal quantum emitters for the envisioned device. We are exploring a number of solutions for the photonic part of the device, in particular we consider different materials (Si3N4 and polymers) together with different geometries. We are working both on the theoretical/simulation side and on the experimental one.

Publications

Other research topics

Antennas: Light-shaping and Plasmonics

Antennas: Light-shaping and Plasmonics

Plasmonic structures prove as test beds for studying light-matter interaction at the fundamental level, while versatile hybrid antennas provide excellent means to modulate emission patterns for various applications.

Random photonic structures

Random photonic structures

We exploit the interplay between order and disorder to control the onset of Anderson localized quasimodes in photonic slabs.

Graphene based nanosensors

Graphene based nanosensors

We envision a new generation of sensors at the nanoscale exploiting different coupling mechanisms between single emitters and a graphene monolayers, such as FRET and Casimir forces.

Transport in turbid media

Transport in turbid media

Monte Carlo simulations provide an exact solution for the Radiative Transfer Equation in turbid media, overcoming the limits of the diffusive approximation.