6 research outputs found
Effects of correlated and uncorrelated quenched disorder on nearest-neighbor coupled lasers
Quenched disorder is commonly investigated in the context of many body
systems such as a varying magnetic field in interacting spin models, or
frequency variance of interacting oscillators. It is often difficult to study
the effect of disorder on these systems experimentally since it requires a
method to change its properties in a controlled fashion. In this work, we study
the effect of quenched disorder in the form of frequency detuning on a coupled
lasers array using a novel degenerate cavity with tunable disorder and coupling
strength. By controlling the properties of the disorder such as its magnitude
and spatial correlations, we measure the gradual decrease of phase locking due
to the effects of disorder and demonstrate that the effects of disorder depend
on the ratio between its correlation length and the size of the phase locked
cluster.Comment: 13 pages, 12 figure
Chiral states in coupled-lasers lattice by on-site complex potential
The ability to control the chirality of physical devices is of great
scientific and technological importance, from investigations of topologically
protected edge states in condensed matter systems to wavefront engineering,
isolation, and unidirectional communication. When dealing with large networks
of oscillators, the control over the chirality of the bulk states becomes
significantly more complicated and requires complex apparatus for generating
asymmetric coupling or artificial gauge fields. Here we present a new approach
for precise control over the chirality of a triangular array of hundreds of
symmetrically-coupled lasers, by introducing a weak non-Hermitian complex
potential, requiring only local on-site control of loss and frequency. In the
unperturbed network, lasing states with opposite chirality (staggered vortex
and staggered anti-vortex) are equally probable. We show that by tuning the
complex potential to an exceptional point, a nearly pure chiral lasing state is
achieved. While our approach is applicable to any oscillators network, we
demonstrate how the inherent non-linearity of the lasers effectively pulls the
network to the exceptional point, making the chirality extremely resilient
against noises and imperfections
Anyonic-parity-time symmetry in complex-coupled lasers
Non-Hermitian Hamiltonians, and particularly parity-time (PT) and anti-PT
symmetric Hamiltonians, play an important role in many branches of physics,
from quantum mechanics to optical systems and acoustics. Both the PT and
anti-PT symmetries are specific instances of a broader class known as
anyonic-PT symmetry, where the Hamiltonian and the PT operator satisfy a
generalized commutation relation. Here, we study theoretically these novel
symmetries and demonstrate them experimentally in coupled lasers systems. We
resort to complex coupling of mixed dispersive and dissipative nature, which
allows unprecedented control on the location in parameter space where the
symmetry and symmetry-breaking occur. Moreover, tuning the coupling in the same
physical system, allows us to realize the special cases of PT and anti-PT
symmetries. In a more general perspective, we present and experimentally
validate a new relation between laser synchronization and the symmetry of the
underlying non-Hermitian Hamiltonian
Exact mapping between a laser network loss rate and the classical XY Hamiltonian by laser loss control
Recently, there has been growing interest in the utilization of physical systems as heuristic optimizers for classical spin Hamiltonians. A prominent approach employs gain-dissipative optical oscillator networks for this purpose. Unfortunately, these systems inherently suffer from an inexact mapping between the oscillator network loss rate and the spin Hamiltonian due to additional degrees of freedom present in the system such as oscillation amplitude. In this work, we theoretically analyze and experimentally demonstrate a scheme for the alleviation of this difficulty. The scheme involves control over the laser oscillator amplitude through modification of individual laser oscillator loss. We demonstrate this approach in a laser network classical XY model simulator based on a digital degenerate cavity laser. We prove that for each XY model energy minimum there corresponds a unique set of laser loss values that leads to a network state with identical oscillation amplitudes and to phase values that coincide with the XY model minimum. We experimentally demonstrate an eight fold improvement in the deviation from the minimal XY energy by employing our proposed solution scheme