Regelmäßige Veranstaltungen
Titel Referent Datum Ort

Garst, Mirlin, Rockstuhl, Schmalian, Shnirman

Montag, 14.00-15.30 Uhr

10-01

Garst, Rockstuhl

Dienstag, 13.00-14.00 Uhr

10-01

Campus Nord, Geb. 425

Freitag, 15.45-17.15 Uhr

Lehmann HS

Donnerstag, 17.15-18.45 Uhr

Lehmann HS

Supersymmetry transformations in coupled optical waveguides

Physikalisches Kolloquium

Vortragender:

Verónica Ahufinger Breto

Datum:

08.07.2022 15:45

Ort:

Otto-Lehmann-Hörsaal, Physik-Flachbau (Geb. 30.22)

Zugehörigkeit:

Universitat Autònoma de Barcelona

Gastgeber:

Prof. Dr. Carsten Rockstuhl

Abstract

In the last few decades, the mathematical concept of supersymmetry (SUSY) has been
extended from Particle Physics to other fields and applied for instance to Optics [1] and to discrete
waveguide lattices [2]. In this talk, we will review some recent results on the use of SUSY (i) to design
integrated photonic devices with new functionalities and enhanced performances with respect to the
standard ones and (ii) to engineer the topology of photonic structures.
For multimode optical waveguides, continuous SUSY transformations allow obtaining a superpartner
refractive index profile whose guided modes share propagation constants with the original waveguide,
but where the fundamental mode is removed from the spectrum. In conjunction with adiabatic transfer
techniques like Spatial adiabatic passage (SAP) or Stark-Chirped Rapid-Adiabatic-Passage (SCRAP),
we design [3,4] efficient and robust mode-division (de)multiplexing devices.
On the other hand, we also explore discrete SUSY (DSUSY) transformations to perform topological
state engineering in arrays of coupled optical waveguides. Specifically, we examine the potential of
DSUSY transformations to systematically address, alter and reconfigure the topological properties of
a system. To this aim, we theoretically and experimentally study [5] the changes that topologically
protected states in photonic lattices undergo as DSUSY transformations are applied to their host
system. In particular, we consider the simplest system with non-trivial topological properties, the Su-
Schieffer-Heeger (SSH) model and demonstrate how SUSY-induced phase transitions can selectively
suspend and re-establish topological protection of specific states. In addition, making use of the
isospectrality of SUSY transformations, we propose a general and high-fidelity method to prepare
gapped topological modes in discrete systems from a single-site excitation [6]. The method consists
of adiabatically connecting two superpartner structures, deforming the input state into the desired
mode. We demonstrate the method by pumping topological states of the SHH model in an optical
waveguide array.
[1] S. M. Chumakov and K. B. Wolf, Phys. Lett. A 193, 51 (1994).
[2] S. Longhi, Phys. Rev. B 81, 195118 (2010).
[3] G. Queraltó, V. Ahufinger, J. Mompart, Opt. Express 25, 27396 (2017).
[4] D. Viedma, V. Ahufinger, J. Mompart, Opt. Express 29, 39200 (2021).
[5] G. Queraltó et al., Communications Physics 3, 49 (2020).
[6] D. Viedma et al., Opt. Express 30, 23531 (2022).