School of Science, Centre for Quantum Dynamics, Griffith University, Nathan, Australia.
Published: December 2024
AI Article Synopsis
Article Abstract
We place Loudon's quantum treatment of optical phase in in its historical context, and outline research that it inspired. We show how it led Pegg and Barnett to their quantum phase formalism, explaining the challenges that they overcame to define phase operators and phase eigenstates rigorously. We show how the formalism essentially constructs an extended rigged Hilbert space that supports strong limits of the phase operators and includes their eigenstates. We identify the complementarity structure (consisting of mutually unbiased bases and generators of cyclical permutations) underpinning Pegg and Barnett's general approach that gives a quantum-classical correspondence free of the ambiguity of Dirac's commutator-Poisson bracket correspondence.This article is part of the theme issue 'The quantum theory of light'.
In this Letter, we present a theoretical study based on the Lorentz function and harmonic oscillator model to explore temporal dynamics of charge transfer plasmon (CTP) resonances. By fitting scattering curves and near-field oscillations, we determine the dephasing time of CTP modes in conductively connected gold nanodisk dimers. We show that, compared with the well-known particle plasmon and dimer plasmon modes, the CTP mode has a narrow spectral width and longer lifetime.
Hopfield neural networks (HNNs) promise broad applications in areas such as combinatorial optimization, memory storage, and pattern recognition. Among various implementations, optical HNNs are particularly interesting because they can take advantage of fast optical matrix-vector multiplications. Yet their studies so far have mostly been on the theoretical side, and the effects of optical imperfections and robustness against memory errors remain to be quantified.
We experimentally demonstrate a cost-effective dual-polarization quadrature phase shift keying (DP-QPSK) coherent passive optical network (PON) system that operates at 100 Gbits/s/λ. This system utilizes distributed feedback lasers (DFBs) and a carrier recovery algorithm facilitated by a bifunctional frequency-domain pilot tone (FPT). To reduce costs in coherent PON implementations, low-cost DFBs are employed as the sole light sources, replacing the more expensive external cavity lasers (ECLs) at both the optical line terminal (OLT) and the optical network units (ONUs).
Holographically designed aperiodic lattices (ALs) have proven to be an exciting engineering technique for achieving electrically switchable single- or multi-frequency emissions in terahertz (THz) semiconductor lasers. Here, we employ the nonlinear transfer matrix modeling method to investigate multi-wavelength nonlinear (sum- or difference-) frequency generation within an integrated THz (idler) laser cavity that also supports optical (pump and signal) waves. The laser cavity includes an aperiodic lattice, which engineers the idler photon lifetimes and effective refractive indices.
Micromodification in bulk undoped polymethylmethacrylate (PMMA) by single focused (numerical aperture (NA) = 0.25), 1030-nm 250-fs laser pump pulses was explored by pump self-transmittance; optical, 3D-scanning confocal photoluminescence (PL); Raman micro-spectroscopy; and optical polarimetric and interferometric microscopy. Starting from the threshold pulse energy = 0.
