14 January

Non-Hermitian photonics: Fano-like Purcell effect and complex modal volume

Tuesday 14 January 2020, 12:00pm

ICN2 Seminar Hall, ICN2 Building, UAB

Prof. Massimo Gurioli, Department of Physics and Astronomy, University of Florence, Italy 

Abstract: Optical resonators are basic elements for a huge variety of devices, from lasers to sensors. They are also at the basis of important quantum electrodynamic effects, such as tailoring the spontaneous emission via the Purcell effect. Optical resonators are therefore of the utmost relevance in many different fields and they have been extensively investigated during the last century, still some important revisions of their understanding are recently emerged in the framework on non-Hermitian theories.

The basis of the novel models is the open nature of any optical resonator, since photons cannot be confined in a finite volume for infinite time. This simple and well known fact implies complex eigenvalues and eigenvectors of the photonic master equations, leading to a deep revision of the famous expression for the Purcell factor, with counterintuitive effects, such as complex modal volume, Fano-like local density of states and even negative radiative rate contributions [1-3].

We experimentally demonstrate all these predictions in cavities on photonic crystal slabs with relatively low optical loss. Near-field hyperspectral imaging via quantum dot photoluminescence is proved to be a direct tool for detecting the counterintuitive effects of non-Hermitian theories. The experimental results fully agree with the predictions [4,5].


[1] C. Sauvan, PRL 110, 237401 (2013)

[2] E. A. Muljarov, W. Langbein, Phys. Rev. B 94, 235438 (2016)

[3] P. Lalanne et al., Laser Photonics Rev. 12, 1700113 (2018)

[4] K-G. Cognée et al. Optica, 6, 269 (2019)

[5] D. Balestri et al, submitted to PRL.


Hosted by ICREA Prof. Prof. Clivia M. Sotomayor Torres, Phononic and Photonic Nanostructures Group Leader at ICN2