Strong coupling between vibrational modes and cavity optical modes leads to the formation of vibration-cavity polaritons, separated by the vacuum Rabi splitting. The splitting depends on the square root of the concentration of absorbers confined in the cavity, which has important implications on the response of the coupled system after ultrafast infrared excitation. In this work, we report on solutions of W(CO) in hexane with a concentration chosen to access a regime that borders on weak coupling. Under these conditions, large fractions of the W(CO) oscillators can be excited, and the anharmonicity of the molecules leads to a commensurate reduction in the Rabi splitting. We report excitation fractions > 0.4, depending on excitation pulse intensity, and show drastic increases in transmission that can be modulated on the picosecond time scale. In comparison to previous experiments, the transient spectra that we observe are much simpler because excited-state transitions lie outside of the transmission spectrum of the cavity, thereby contributing only weakly to the spectra. We find that the Rabi splitting recovers with the characteristic vibrational relaxation lifetime and anisotropy decay of uncoupled W(CO), implying that polaritons are not directly involved in the relaxation we observe after the first few ps. The results help corroborate the model that we proposed to describe the results at higher concentrations and show that the ground-state bleach of cavity-coupled molecules has a broad, multisigned spectral response.
Nanoscale control over the second-order photon correlation function g (2) (τ ) is critical to emerging research in nonlinear nanophotonics and integrated quantum information science. Here we report on quasiparticle control of photon bunching with g (2) (0) > 45 in the cathodoluminescence of nanodiamond nitrogen vacancy (NV 0 ) centers excited by a converged electron beam in an aberrationcorrected scanning transmission electron microscope. Plasmon-mediated NV 0 cathodoluminescence exhibits a 16-fold increase in luminescence intensity correlated with a three fold reduction in photon bunching compared with that of uncoupled NV 0 centers. This effect is ascribed to the excitation of single temporally uncorrelated NV 0 centers by single surface plasmon polaritons. Spectrally resolved Hanbury Brown-Twiss interferometry is employed to demonstrate that the bunching is mediated by the NV 0 phonon sidebands, while no observable bunching is detected at the zero-phonon line. The data are consistent with fast phonon-mediated recombination dynamics, a conclusion substantiated by agreement between Bayesian regression and Monte Carlo models of superthermal NV 0 luminescence.PACS numbers: 42.50. Ar, 78.60.Hk, 73.20.Mf The efficiency of second-order nonlinearities scales proportionally with g (2) (0), the second-order photon correlation function at zero delay of the driving optical field [1,2]. Nanoscale superthermal light sources exhibiting photon bunching with g (2) (0) > 2 thus provide a path toward high-efficiency nonlinear nanophotonics. Moreover, control of g (2) (τ ) is increasingly critical for quantum nanophotonics applications [3,4]. However, despite increasing evidence of coherent quantum behavior in nanoplasmonic systems [5,6], experimental plasmonic control of g (2) (τ ) has been realized only in Purcell enhancement of the anti-bunching dynamics of plasmoncoupled emitters [7].Compared with photoluminescence (PL) spectroscopy, cathodoluminescence (CL) yields vastly improved spatial resolution in measurements of g (2) (τ ). This fact was leveraged in the first explorations of CL photon statistics, in which photon antibunching was observed from individual NV 0 centers in nanodiamonds and from point defects in hexagonal boron nitride excited by an 80-keV electron beam [8-10]. More critically, photon bunching has been observed in the CL of ensembles of quantum emitters * Matthew.Feldman@vanderbilt.edu † lawriebj@ornl.gov whose PL exhibits g (2) (τ ) ≈ 1 because of the absence of temporal correlations between optically excited emitters. In contrast to PL, the scanning transmission electron microscope (STEM) primarily excites higher-energy modes, such as the 30-eV bulk plasmon in diamond [11]. The subsequent cascading excitation of multiple excitons and color centers for each plasmon, within an ∼ 10 fs excitation window, explains recent observations of photon bunching of g (2) (0) − 1 > 4 in CL spectroscopy of ensembles of NV 0 centers in nanodiamond [12,13]. However, understanding the classical and quantum optical proper...
No abstract
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.