Supersymmetry unveiled in periodic optical media (Vol. 46 No. 3)

Supersymmetry unveiled in periodic optical media
Supersymmetric grating that realizes a frequency comb transmission filter

Supersymmetry (SUSY) was conjectured in quantum field theory as a means to unify bosons and fermions. While SUSY would be helpful in solving paradoxes such as the cosmological constant problem, its evidence in particle physics remains elusive. However, SUSY can be applied to other areas of physics, ranging from quantum mechanics to optics.

Supersymmetric optics is a recent and promising research field. It enables to synthesize dielectric media with target scattering properties and with less stringent material requirements than e.g. metamaterials synthesized by transformation optics. SUSY optical structures can realize efficient mode conversion, spatial multiplexing, transparent interfaces and optical intersections.

In this work, the author has now disclosed the SUSY property of periodic optical media. SUSY in grating structures can find important applications to the synthesis of Bragg filters and distributed-feedback optical cavities. For example, the author describes how multiple SUSY can be used to design frequency comb transmission filters (see Figure).

Optical SUSY in periodic media is a powerful design tool that can be extended to include gain and loss, i.e. distributed feedback lasers, as well as optical media with parity-time (PT) symmetry.

S. Longhi,, Supersymmetric Bragg gratings, J. Opt. 17, 045803 (2015)