82 research outputs found

    Practical Guide to the Piccolo Autopilot

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    In support of a UAV contract the Piccolo SL and Piccolo II autopilots were installed and operated on various aircraft. Numerous problems with the autopilot setup and analysis processes were found along with numerous problems with documentation and autopilot system information. Major areas of concern are identified along with objectives to eliminate the major areas of concern. Piccolo simulator vehicle gain calculations and Piccolo generation 2 version 2.1.4 control laws are reverse engineered. A complete modeling guide is created. Methods are developed to perform and analyze doublet maneuvers. A series of flight procedures are outlined that include methods for tuning gains. A series of MATLAB graphical user interfaces were created to analyze flight data and pertinent control loop data for gain tuning.Mechanical & Aerospace Engineerin

    Sculpting ultrastrong light-matter coupling through spatial matter structuring

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    The central theme of cavity quantum electrodynamics is the coupling of a single optical mode with a single matter excitation, leading to a doublet of cavity polaritons which govern the optical properties of the coupled structure. Especially in the ultrastrong coupling regime, where the ratio of the vacuum Rabi frequency and the quasi-resonant carrier frequency of light, ΩR/ωc\Omega_{\mathrm R}/\omega_{\mathrm c}, approaches unity, the polariton doublet bridges a large spectral bandwidth 2ΩR2\Omega_{\mathrm R}, and further interactions with off-resonant light and matter modes may occur. The resulting multi-mode coupling has recently attracted attention owing to the additional degrees of freedom for designing light-matter coupled resonances, despite added complexity. Here, we experimentally implement a novel strategy to sculpt ultrastrong multi-mode coupling by tailoring the spatial overlap of multiple modes of planar metallic THz resonators and the cyclotron resonances of Landau-quantized two-dimensional electrons, on subwavelength scales. We show that similarly to the selection rules of classical optics, this allows us to suppress or enhance certain coupling pathways and to control the number of light-matter coupled modes, their octave-spanning frequency spectra, and their response to magnetic tuning. This offers novel pathways for controlling dissipation, tailoring quantum light sources, nonlinearities, correlations as well as entanglement in quantum information processing

    Mode-multiplexing deep-strong light-matter coupling

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    Dressing quantum states of matter with virtual photons can create exotic effects ranging from vacuum-field modified transport to polaritonic chemistry, and may drive strong squeezing or entanglement of light and matter modes. The established paradigm of cavity quantum electrodynamics focuses on resonant light-matter interaction to maximize the coupling strength ΩR/ωc\Omega_\mathrm{R}/\omega_\mathrm{c}, defined as the ratio of the vacuum Rabi frequency and the carrier frequency of light. Yet, the finite oscillator strength of a single electronic excitation sets a natural limit to ΩR/ωc\Omega_\mathrm{R}/\omega_\mathrm{c}. Here, we demonstrate a new regime of record-strong light-matter interaction which exploits the cooperative dipole moments of multiple, highly non-resonant magnetoplasmon modes specifically tailored by our metasurface. This multi-mode coupling creates an ultrabroadband spectrum of over 20 polaritons spanning 6 optical octaves, vacuum ground state populations exceeding 1 virtual excitation quantum for electronic and optical modes, and record coupling strengths equivalent to ΩR/ωc=3.19\Omega_\mathrm{R}/\omega_\mathrm{c}=3.19. The extreme interaction drives strongly subcycle exchange of vacuum energy between multiple bosonic modes akin to high-order nonlinearities otherwise reserved to strong-field physics, and entangles previously orthogonal electronic excitations solely via vacuum fluctuations of the common cavity mode. This offers avenues towards tailoring phase transitions by coupling otherwise non-interacting modes, merely by shaping the dielectric environment

    A cross-cultural study of music in history

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    Music lives in every culture, yet most investigations into music are based on Western music and Western listeners. This has not only ignored the cultural richness in music itself, but has also limited the impact of research on large varieties of societies. In reality, music is multi-cultural, multi-lingual and multi-facet. Evident in communication, education and healthcare systems, multi-cultural challenges have also merged into many aspects of our historical and contemporary societies. Moreover, rapid changes of the society and fast evolutionary development of media and technology have enriched world wealth of music. In this paper, we demonstrate that music has a rich but cross-cultural foundation in history with significance in linguistics, health and art. Consequently, we present a multi-disciplinary or multi-cultural study of music in history, revealing its significance in linguistics, health and wellbeing

    Real-space nanophotonic field manipulation using non-perturbative light–matter coupling

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    The achievement of large values of the light–matter coupling in nanoengineered photonic structures can lead to multiple photonic resonances contributing to the final properties of the same hybrid polariton mode. We develop a general theory describing multi-mode light–matter coupling in systems of reduced dimensionality, and we explore their phenomenology, validating our theory’s predictions against numerical electromagnetic simulations. On one hand, we characterize the spectral features linked with the multi-mode nature of the polaritons. On the other hand, we show how the interference between different photonic resonances can modify the real-space shape of the electromagnetic field associated with each polariton mode. We argue that the possibility of engineering nanophotonic resonators to maximize multi-mode mixing, and to alter the polariton modes via applied external fields, could allow for the dynamical real-space tailoring of subwavelength electromagnetic fields

    Tailored subcycle nonlinearities of ultrastrong light-matter coupling

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    We explore the nonlinear response of tailor-cut light-matter hybrid states in a novel regime, where both the Rabi frequency induced by a coherent driving field and the vacuum Rabi frequency set by a cavity field are comparable to the carrier frequency of light. In this previously unexplored strong-field limit of ultrastrong coupling, subcycle pump-probe and multi-wave mixing nonlinearities between different polariton states violate the normal-mode approximation while ultrastrong coupling remains intact, as confirmed by our mean-field model. We expect such custom-cut nonlinearities of hybridized elementary excitations to facilitate non-classical light sources, quantum phase transitions, or cavity chemistry with virtual photons

    Non-adiabatic stripping of a cavity field from electrons in the deep-strong coupling regime

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    Atomically strong light pulses can drive sub-optical-cycle dynamics. When the Rabi frequency-the rate of energy exchange between light and matter-exceeds the optical carrier frequency, fascinating non-perturbative strong-field phenomena emerge, such as high-harmonic generation and lightwave transport. Here, we explore a related novel subcycle regime of ultimately strong light-matter interaction without a coherent driving field. We use the vacuum fluctuations of nanoantennas to drive cyclotron resonances of two-dimensional electron gases to vacuum Rabi frequencies exceeding the carrier frequency. Femtosecond photoactivation of a switch element inside the cavity disrupts this 'deep-strong coupling' more than an order of magnitude faster than the oscillation cycle of light. The abrupt modification of the vacuum ground state causes spectrally broadband polarization oscillations confirmed by our quantum model. In the future, this subcycle shaping of hybrid quantum states may trigger cavity-induced quantum chemistry, vacuum-modified transport or cavity-controlled superconductivity, opening new scenarios for non-adiabatic quantum optics. Deactivation of deep-strong light-matter coupling is achieved by femtosecond switching of terahertz cavities. This disruption leads to pronounced high-frequency polarization oscillations evolving much faster than the oscillation cycle of light

    Direct Observation of ultrafast exciton Formation in a monolayer of WSe2

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    Many of the fundamental optical and electronic properties of atomically thin transition metal dichalcogenides are dominated by strong Coulomb interactions between electrons and holes, forming tightly bound atom-like states called excitons. Here, we directly trace the ultrafast formation of excitons by monitoring the absolute densities of bound and unbound electron hole pairs in single monolayers of WSe2 on a diamond substrate following femtosecond nonresonant optical excitation. To this end, phase locked mid-infrared probe pulses and field-sensitive electro-optic sampling are used to map out the full complex-valued optical conductivity of the nonequilibrium system and to discern the hallmark low-energy responses of bound and unbound pairs. While the spectral shape of the infrared response immediately after above-bandgap injection is dominated by free charge carriers, up to 60% of the electron-hole pairs are bound into excitons already on a subpicosecond time scale, evidencing extremely fast and efficient exciton formation. During the subsequent recombination phase, we still find a large density of free carriers in addition to excitons, indicating a nonequilibrium state of the photoexcited electron-hole system
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