A new class of devices exploiting Fano resonances and with important applications in information technology have been suggested, theoretically analyzed and experimentally demonstrated.
Typically, the resonance of a system is described by a frequency and a lifetime, leading to a Lorentzian lineshape function. If
the system instead involves interference between a discrete resonance and a continuum, a Fano lineshape appears with
fundamentally different characteristics. Here, the Fano resonance is used to make a novel integrated mirror, enabling
realization of Fano lasers, Fano switches and quantum Fano devices. These devices challenge well-accepted paradigms for
photonic devices. The goals of the project are to demonstrate a laser with modulation bandwidth greatly exceeding all
existing lasers; a nanolaser with linewidth three orders of magnitude smaller than existing nanocavity lasers; and a switch
that operates at femtojoule energies and provides gain. Such devices are important for realizing high-speed optical
interconnects and networks between and within chips. An increasing fraction of the global energy consumption is being used
for data communication, and photonics operating at very high data rates with ultra-low energy per bit has been identified as a
key technology to enable a sustainable growth of capacity demands. Existing device designs, however, cannot just be
scaled down to reach the goals for next-generation integrated devices. The Fano mirror will also be used to demonstrate
control at the single-photon level, which will enable high-quality on-demand single-photon sources, which are much
demanded devices in photonic quantum technology. These devices all rely on the unique properties of the Fano mirror,
which provides a new resource for ultrafast dynamic control, noise suppression and ultra-low energy operation. Using
photonic crystal technology the project will achieve its goals in a concerted effort involving development of new theory, new
nanofabrication techniques and advanced experiments.
The project has explored and demonstrated two types of Fano lasers, i.e. based on photonic crystal slabs and on nanobeams. It has been
shown that by using Fano laser geometry the intrinsic linewidth of the laser can be reduced considerably. It was also shown that the
Fano laser can be controlled optically, leading to the generation and control of short optical pulses. The project has also led to important
advancements in fabrication technology, leading to the experimetal demonstration of a room-temperature nanolaser with the lowest
threshold current observed for any type of semiconductor laser at room temperature. Significant modeling efforts have also been undertaken,
leading to a comprehensive understanding of the fudamental properties of Fano lasers and the identification of new ideas which could not be pursued within
the project.
