Control Of Light-matter Interactions Research Articles

Chiral Nanophotonics and Control of Light-matter Interaction

Chirality, a fundamental symmetry property, denotes the intrinsic handedness of an object, rendering it non-superimposable onto its mirror image via translations and rotations due to the lack of inversion symmetry. This property extends beyond tangible entities to include light, giving rise to a field of chiral nanophotonics. Chiral nanophotonics studies how chiral light interacts with chiral matter at the nanoscale. Understanding chiral light-matter interaction holds the key to novel applications, spanning from ultrasensitive chiral molecule sensing to quantum information processing. We introduce important concepts and recent efforts in chiral nanophotonics and its application.

Electrically driven photon statistics engineering in quantum-dot circuit quantum electrodynamics

Quantum-dot circuit quantum electrodynamics (QD-cQED) has enabled the probe and control of light-matter interaction at the elementary level, with the demonstration of nonclassical photon sources driven by inelastic electron tunneling. Due to the absence of the photon blockade mechanism, an general scheme for photon statistics engineering in QD-cQED is lacking. Based on current-driven joint interference effect, the authors propose here an all-electrical scheme to achieve arbitrary photon statistics with classical or quantum correlation by simply controlling bias voltage.

Recent Progress in Chiral Topological Quantum Interface

Chiral quantum optics and Topological photonics are both emerging field of research, which have attracted great attention in recent years. Chiral quantum optics provides a new approach to achieve full quantum control of light-matter interaction in a novel manner, which has potential possibility for the implementation of complex quantum information networks. Meanwhile, topological photonics provides a novel route for designing and realizing optical device with unprecedented functionality, such as robust light propagation, the immunity to various structural imperfection, back-scattering suppression as well as unidirectional transmission. The application of topological photonics in chiral quantum optics will promote the whole performance of integrated quantum device with topological protection. In this review, we summarize the progress of chiral quantum optics and topological photonics firstly. Then, we mainly focus on the research of topological chiral edge states based on photonic quantum spin-Hall effect and photonic quantum valley-Hall effect. Furthermore, we introduce the recent work of chiral topological quantum interface formed by embedding quantum dot into the interface between two topologically distinct photonic crystal structures. At last, we give short outlook on the future development direction and prospect for application of topological chiral quantum interface.

Vacuum-field-induced THz transport gap in a carbon nanotube quantum dot

The control of light-matter interaction at the most elementary level has become an important resource for quantum technologies. Implementing such interfaces in the THz range remains an outstanding problem. Here, we couple a single electron trapped in a carbon nanotube quantum dot to a THz resonator. The resulting light-matter interaction reaches the deep strong coupling regime that induces a THz energy gap in the carbon nanotube solely by the vacuum fluctuations of the THz resonator. This is directly confirmed by transport measurements. Such a phenomenon which is the exact counterpart of inhibition of spontaneous emission in atomic physics opens the path to the readout of non-classical states of light using electrical current. This would be a particularly useful resource and perspective for THz quantum optics.

Single-cycle all-fiber frequency comb

Single-cycle pulses with deterministic carrier-envelope phase enable the study and control of light-matter interactions at the sub-cycle timescale, as well as the efficient generation of low-noise multi-octave frequency combs. However, current single-cycle light sources are difficult to implement and operate, hindering their application and accessibility in a wider range of research. In this paper, we present a single-cycle 100 MHz frequency comb in a compact, turn-key, and reliable all-silica-fiber format. This is achieved by amplifying 2 $\mu$m seed pulses in heavily-doped Tm:fiber, followed by cascaded self-compression to yield 6.8 fs pulses with 215 kW peak power and 374 mW average power. The corresponding spectrum covers more than two octaves, from below 700 nm up to 3500 nm. Driven by this single-cycle pump, supercontinuum with 180 mW of integrated power and a smooth spectral amplitude between 2100 and 2700 nm is generated directly in silica fibers. To broaden applications,few-cycle pulses extending from 6 $\mu$m to beyond 22 $\mu$m with long-term stable carrier-envelope phase are created using intra-pulse difference frequency, and electro-optic sampling yields comb-tooth-resolved spectra. Our work demonstrates the first all-fiber configuration that generates single-cycle pulses, and provides a practical source to study nonlinear optics on the same timescale.

Circuit quantum electrodynamics

Quantum mechanical effects at the macroscopic level were first explored in Josephson junction-based superconducting circuits in the 1980's. In the last twenty years, the emergence of quantum information science has intensified research toward using these circuits as qubits in quantum information processors. The realization that superconducting qubits can be made to strongly and controllably interact with microwave photons, the quantized electromagnetic fields stored in superconducting circuits, led to the creation of the field of circuit quantum electrodynamics (QED), the topic of this review. While atomic cavity QED inspired many of the early developments of circuit QED, the latter has now become an independent and thriving field of research in its own right. Circuit QED allows the study and control of light-matter interaction at the quantum level in unprecedented detail. It also plays an essential role in all current approaches to quantum information processing with superconducting circuits. In addition, circuit QED enables the study of hybrid quantum systems interacting with microwave photons. Here, we review the coherent coupling of superconducting qubits to microwave photons in high-quality oscillators focussing on the physics of the Jaynes-Cummings model, its dispersive limit, and the different regimes of light-matter interaction in this system. We discuss coupling of superconducting circuits to their environment, which is necessary for coherent control and measurements in circuit QED, but which also invariably leads to decoherence. Dispersive qubit readout, a central ingredient in almost all circuit QED experiments, is also described. Following an introduction to these fundamental concepts that are at the heart of circuit QED, we discuss important use cases of these ideas in quantum information processing and in quantum optics.

Progress on exciton polariton photonics

<p indent="0mm">Control of light-matter interactions is crucial for the development of cavity quantum electrodynamics. In the 1950s, Huang developed a model to describe photon-phonon interactions in solid-state systems. In this model, when a phonon and a photon exchange energy continuously and coherently, the system can reach a strong coupling regime and a new quasiparticle called “polariton” can be formed. Huang’s theory also describes the dispersion of phonon polaritons. This theory has been applied to semiconductors by Hopfield, wherein an exciton and a photon can couple with each other, reaching new eigenmodes called “exciton-polaritons”. Subsequently, vacuum Rabi splitting has been observed in a microcavity that is strongly coupled to a single atom or a single quantum dot. Microcavities of a higher quality factor display macroscopic quantum phenomena such as polariton condensation, superfluidity, and vortices. By applying nanofabrication techniques on the cavity or controlling the beam profile of a pumping laser, various potentials can be induced in polariton systems that enable the manipulation of macroscopic quantum states. Excitons exhibit much larger binding energies and oscillator strengths in emerging materials such as organic semiconductors, perovskites, and two-dimensional semiconductors, providing a new platform to extend polariton physics to room-temperature devices. Microcavity exciton-polaritons are the leading candidate systems for studying quantum optics and condensed matter physics. This review first introduces microcavity exciton-polaritons, including the formation of exciton-polaritons, energy-momentum dispersion of exciton-polaritons, and polariton systems classified by the gain medium. We then introduce several systems to achieve strong coupling and a microspectroscopic technique to investigate exciton-polaritons. The third section provides an analysis of the macroscopic quantum states of exciton-polaritons and describes how to manipulate the quantum state using nanofabrication and optical pumping techniques. The fourth section summarizes several new materials that have been used to study exciton-polaritons at room temperature. The last section summarizes this review, and provides perspectives in both theories and experiments.

(Invited) Novel Optical Phenomena in Nanoplasmonic Arrays

Extraordinary optical transmission (EOT) through subwavelength-scale hole arrays in metal films, discovered nearly 20 years ago by Ebbesen and co-workers, has spurred intense effort in nano-plasmonics and nano-optics. To date virtually all the measurements in this field have involved intricate hole arrays in metal films fabricated using complex lithography and etching. This results result in structures less than a millimeter square, which necessitates a complex setup of an optical microscope tied to a spectrophotometer for measurements. We describe a far simpler system that exhibits the EOT, that does not require any lithography, and is scalable to large areas, and generate intense optical fields that serve as a platform for novel luminescent phenomena. We experimentally and theoretically demonstrate that a continuous gold film on a periodically textured substrate of nanocup arrays, surprisingly exhibits extraordinary optical transmission, even though no holes were etched in the film.To fabricate nanocup arrays we utilized a polycarbonate master with a periodic array of nanocups (of pitch 750 nm) and replicated the inverse of that pattern to a poly-dimethyl-siloxane (PDMS) elastomer. The PDMS elastomer was then used to nanoimprint the nanocup array on a polystyrene film. A thin non-conformal gold film was sputter-deposited on the polystyrene with angle-directed deposition. Although the gold film was continuous, its thickness varied spatially, with the film being thinnest at the bottom of the nanocup. Optical measurements [1] on the gold-coated nanocup array revealed an extraordinary transmission peak at a wavelength just smaller than the period, with an enhancement of ~2.5 compared to the classically expected value, even though there were no holes in the film. Scattering matrix simulations model well the transmission and reflectance measurements when an ultrathin gold layer (~5 nm), smaller than the skin depth, is retained at the bottom of the nanocups. Electric field intensities are enhanced by >100 within the nanocup. The ultrathin gold layer causes transmission through it with an enhancement of the field intensity by ~40.These arrays are a novel platform for nanoscale luminescent phenomena. Quantum dots embedded within the nanocup arrays show [2] a radiative decay rate that is increased by as much as a factor of 20, from the interaction of the strong optical field with the luminescent quantum dot. In an emerging bio-marker application we demonstrate [3] slowed release rate from medicinal coatings on these nanocups – a feature that could be useful to many emerging drug therapies. Novel metasurfaces of nanocup and nanocone arrays offer a novel platform for nanoplasmonics, nanophotonics, control of light matter interactions, and surface charges [4]. Such nano-arrays hence provide a novel platform for luminescent nano-materials.We acknowledge the financial support from the National Science Foundation through grants CMMI-1265844 and CMMI-170648.1. A. Peer and R. Biswas, Nanoscale 8, 4657 - 4666 (2016).2. A. Peer, Z. Hu, A. Singh, J. A. Hollingsworth, R. Biswas, and H. Htoon, Small 13, 1700660 (2017).3. A. Peer, R. Dhakal, R. Biswas, J. Kim, Nanoscale Patterning of Biopolymers for functional bio-surfaces and controlled drug release, Nanoscale 8, 18654–18664 (2016).4. Q. Li, A. Peer, I. Cho, R. Biswas, J. Kim, Replica molding-based nanopatterning of tribocharge on elastomer with application to electrohydrodynamic nanolithography, Nature Communications 9, 974 (2018). Figure 1

Elucidating Energy Pathways through Simultaneous Measurement of Absorption and Transmission in a Coupled Plasmonic-Photonic Cavity.

Control of light-matter interactions is central to numerous advances in quantum communication, information, and sensing. The relative ease with which interactions can be tailored in coupled plasmonic-photonic systems makes them ideal candidates for investigation. To exert control over the interaction between photons and plasmons, it is essential to identify the underlying energy pathways which influence the system's dynamics and determine the critical system parameters, such as the coupling strength and dissipation rates. However, in coupled systems which dissipate energy through multiple competing pathways, simultaneously resolving all parameters from a single experiment is challenging as typical observables such as absorption and scattering each probe only a particular path. In this work, we simultaneously measure both photothermal absorption and two-sided optical transmission in a coupled plasmonic-photonic resonator consisting of plasmonic gold nanorods deposited on a toroidal whispering-gallery-mode optical microresonator. We then present an analytical model which predicts and explains the distinct line shapes observed and quantifies the contribution of each system parameter. By combining this model with experiment, we extract all system parameters with a dynamic range spanning 9 orders of magnitude. Our combined approach provides a full description of plasmonic-photonic energy dynamics in a weakly coupled optical system, a necessary step for future applications that rely on tunability of dissipation and coupling.

Broadband coherent hyperspectral near-field imaging of plasmonic nanostructures.

We develop a coherent hyperspectral near-field microscope using a combined nano-Fourier Transform Infra-Red (FTIR) spectroscope and a scattering Scanning Near-field Optical Microscope (s-SNOM) illuminated by an ultra-broadband few-cycle femtosecond source, spanning a spectrum from 660 to 1050 nm. Using this spatio-spectral approach, we resolve hyperspectral near-field response of a single plasmonic nano-antennas over 450 nm bandwidth with a spatial resolution of 40 nm and a spectral resolution of 50 cm-1. In particular, we identify the electric near-field spatial distribution of the dipole resonant mode of various nano-antennas and observe, in accordance with previous theoretical reports, that those are spectrally red-shifted from their far-field response. Moreover, we are able to spectrally and spatially differentiate the near-field distribution of the dipole and quadrupole modes at the single nanoparticle level. Being coherent and short-pulsed, our technique opens the path for optical ultrafast characterization and control of light-matter interaction at the nanoscale.

Transmission and plasmonic resonances on quasicrystal metasurfaces

The control of light-matter interaction in metasurfaces offers an unexplored potential for the excitation and manipulation of light. Here, we combine experimental terahertz time-domain spectroscopy and near-field scanning terahertz microscopy to demonstrate the role of reciprocal vectors in the transmission and plasmonic resonances of quasicrystal metasurfaces. An investigation of two-dimensional metasurface structures with different rotationally symmetric quasicrystal arrangements demonstrates that the transmission minima resulting from Wood's anomaly are directly related to the surface plasmon resonances. We also find that the surface plasmon resonances of the quasicrystal metasurface were determined by the reciprocal vectors, which could be well explained by the coupling condition of the resonances, and the characteristic frequencies remain un-shifted under various slit sizes. Our findings demonstrate a new potential in developing novel plasmonic metasurfaces.

(13)C or Not (13)C: Selective Synthesis of Asymmetric Carbon-13-Labeled Platinum(II) cis-Acetylides.

Asymmetric isotopic labeling of parallel and identical electron- or energy-transfer pathways in symmetrical molecular assemblies is an extremely challenging task owing to the inherent lack of isotopic selectivity in conventional synthetic methods. Yet, it would be a highly valuable tool in the study and control of complex light-matter interactions in molecular systems by exclusively and nonintrusively labeling one of otherwise identical reaction pathways, potentially directing charge and energy transport along a chosen path. Here we describe the first selective synthetic route to asymmetrically labeled organometallic compounds, on the example of charge-transfer platinum(II) cis-acetylide complexes. We demonstrate the selective (13)C labeling of one of two acetylide groups. We further show that such isotopic labeling successfully decouples the two ν(C≡C) in the mid-IR region, permitting independent spectroscopic monitoring of two otherwise identical electron-transfer pathways, along the (12)C≡(12)C and (13)C≡(13)C coordinates. Quantum-mechanical mixing leads to intriguing complex features in the vibrational spectra of such species, which we successfully model by full-dimensional anharmonically corrected DFT calculations, despite the large size of these systems. The synthetic route developed and demonstrated herein should lead to a great diversity of asymmetric organometallic complexes inaccessible otherwise, opening up a plethora of opportunities to advance the fundamental understanding and control of light-matter interactions in molecular systems.

Actively tunable thin films for visible light by thermo‐optic modulation of ZnO

Applications of active control of light matter interactions within integrated photonics, hyper‐spectral imaging, reconfigurable lasers, and selective bio‐surfaces have enormously increased the demand for realization of optical modulation covering the spectrum from ultraviolet (UV) up to infrared (IR) wavelength range. In this study, we demonstrate ZnO‐based actively tunable perfect absorber operating within UV and visible spectrum with more than 5 nm shift in the resonant absorption wavelength. Using spectroscopic ellipsometry technique, we extract temperature‐dependent optical constants of atomic layer‐deposited ZnO within 0.3–1.6 and 4–40 μm spectra. We also observe bandgap narrowing of ZnO at elevated temperatures due to lattice relaxation verified by the red‐shift of phonon‐modes. At around its bandgap, refractive index variations up to 0.2 is obtained and ZnO is shown to exhibit thermo‐optic coefficient as high as 9.17 × 10−4 K−1 around the bandgap which is the largest among well‐known large bandgap materials.

Vacuum-Assisted Generation and Control of Atomic Coherences at X-Ray Energies

The control of light-matter interaction at the quantum level usually requires coherent laser fields. But already an exchange of virtual photons with the electromagnetic vacuum field alone can lead to quantum coherences, which subsequently suppress spontaneous emission. We demonstrate such spontaneously generated coherences (SGC) in a large ensemble of nuclei operating in the x-ray regime, resonantly coupled to a common cavity environment. The observed SGC originates from two fundamentally different mechanisms related to cooperative emission and magnetically controlled anisotropy of the cavity vacuum. This approach opens new perspectives for quantum control, quantum state engineering and simulation of quantum many-body physics in an essentially decoherence-free setting.

Photoelectric Energy Conversion of Plasmon-Generated Hot Carriers in Metal–Insulator–Semiconductor Structures

Plasmonic excitation in metals has received great attention for light localization and control of light-matter interactions at the nanoscale with a plethora of applications in absorption enhancement, surface-enhanced Raman scattering, or biosensing. Electrically active plasmonic devices, which had remained underexplored, have recently become a growing field of interest. In this report we introduce a metal-insulator-semiconductor heterostructure for plasmo-electric energy conversion, a novel architecture to harvest hot-electrons derived from plasmonic excitations. We demonstrate external quantum efficiency (EQE) of 4% at 460 nm using a Ag nanostructured electrode and EQE of 1.3% at 550 nm employing a Au nanostructured electrode. The insulator interfacial layer has been found to play a crucial role in interface passivation, a requisite in photovoltaic applications to achieving both high open-circuit voltages (0.5 V) and fill-factors (0.5), but its introduction simultaneously modifies hot-electron injection and transport. We investigate the influence passivation has on these processes for different material configurations, and characterize different types of transport depending on the initial plasmon energy band, reporting power conversion efficiencies of 0.03% for nanopatterned silver electrodes.

Nanoscale interference patterns of gap-mode multipolar plasmonic fields

Arbitrary spatial distributions of the electric field of light are formed through the interference of individual wavenumber mode fields with appropriate amplitudes and phases, while the maximum wavenumber in the far field is limited by the wavelength of light. In contrast, localized surface plasmons (LSPs) possess the ability to confine photons strongly into nanometer-scale areas, exceeding the diffraction limit. In particular, gap-mode LSPs produce single-nanometer-sized, highly intense localized fields, known as hot spots. Here, we show the nanoscale spatial profiles of the LSP fields within hot spots, which exhibit complicated fine structures, rather than single peaks. The nanopatterns are created by constructive and destructive interferences of dipolar, quadrupolar, and higher-order multipolar plasmonic modes, which can be drastically altered by controlling parameters of the excitation optical system. The analysis in this study would be useful for proposing new concepts for manipulation and control of light-matter interactions in nanospaces.

Flexible control of light-matter interaction on the nanoscale

Flexible control of light-matter interaction on the nanoscale

Control of light-matter interaction in microresonators

The spontaneous emission of excitons confined in quantum dots that are embedded in microresonators with a three-dimensional confinement of light has been studied by time-resolved spectroscopy. The available decay channels have been investigated for different resonator types without and with lateral gold coating. For the latter type we were able to demonstrate both of the critical aspects of a control of spontaneous emission: an enhancement for on-resonance of the exciton transition with an optical cavity mode and a deenhancement for off-resonance.