The perfect absorption of electromagnetic waves has promoted many applications, including photovoltaics, radar cloaking, and molecular detection. Unlike conventional methods of critical coupling that ...require asymmetric boundaries or coherent perfect absorption that require multiple coherent incident beams, here we demonstrate single-beam perfect absorption in an on-chip cavity magnonic device without breaking its boundary symmetry. By exploiting magnon-mediated interference between two internal channels, both reflection and transmission of our device can be suppressed to zero, resulting in magnon-induced nearly perfect absorption (MIPA). Such interference can be tuned by the strength and direction of an external magnetic field, thus showing versatile controllability. Furthermore, the same multi-channel interference responsible for MIPA also produces level attraction (LA)-like hybridization between a cavity magnon polariton mode and a cavity photon mode, demonstrating that LA-like hybridization can be surprisingly realized in a coherently coupled system.
By developing a gain-embedded cavity magnonics platform, we create a gain-driven polariton (GDP) that is activated by an amplified electromagnetic field. Distinct effects of gain-driven light-matter ...interaction, such as polariton auto-oscillations, polariton phase singularity, self-selection of a polariton bright mode, and gain-induced magnon-photon synchronization, are theoretically studied and experimentally manifested. Utilizing the gain-sustained photon coherence of the GDP, we demonstrate polariton-based coherent microwave amplification (∼40 dB) and achieve high-quality coherent microwave emission (Q>10^{9}).
The emerging field of cavity spintronics utilizes the cavity magnon polariton (CMP) induced by magnon Rabi oscillations. In contrast to a single-spin quantum system, such a cooperative spin dynamics ...in the linear regime is governed by the classical physics of harmonic oscillators. It makes the magnon Rabi frequency independent of the photon Fock state occupation, and thereby restricts the quantum application of CMP. Here we show that a feedback cavity architecture breaks the harmonic-oscillator restriction. By increasing the feedback photon number, we observe an increase in the Rabi frequency, accompanied with the evolution of CMP to a cavity magnon triplet and a cavity magnon quintuplet. We present a theory that explains these features. Our results reveal the physics of cooperative polariton dynamics in feedback-coupled cavities, and open up new avenues for exploiting the light-matter interactions.
The dissipative light-matter coupling can cause the attraction of two energy levels, i.e., level attraction, when competing with the coherent coupling that induces usual Rabi-level splitting. The ...level attraction shows attractive potential for topological information processing. However, the underlying microscopic quantum mechanism of dissipative coupling still remains unclear although the behavior has been understood to root in the non-Hermitian physics, which brings difficulties in quantifying and manipulating the competition between coherence and dissipation and thereby the flexible control of level attraction. Here, by coupling a magnon mode to a cavity supporting both standing and traveling waves, we identify the traveling-wave state to be responsible for magnon-photon dissipative coupling. By characterizing the radiative broadening of a magnon linewidth, we quantify the coherent and dissipative coupling strengths and their competition. The effective magnon-photon coupling strength, as a net result of competition, is analytically presented using quantum theory to show good agreement with measurements. In this manner, we extend the control dimension of level attraction by tuning field torque on magnetization or global cavity geometry. Our findings provide insights on engineered coupled harmonic oscillator systems.
Single wire devices are generally fabricated to study the electrical and photoelectric behaviors of semiconductor nanowires(NWs);however detriment or contamination can hardly be avoided during ...manipulation of NWs under focused ion and electron beams.This could not be a trivial factor for III-V NWs which are candidates for high efficiency solar energy harvesting and sensitive photodetection.In this study an alternative way to probe the photoconductive property of individual epitaxial GaAs NWs is presented.For the sample preparation,a uniform spin-coated layer of polymer was selected to be the supporting medium for the vertically aligned NWs structure;then the adequate thinning and polishing of the sample exposed the NW tip and also achieved the required height of NW.An external power adjustable laser was introduced as the excitation source,and the dark and photoconductive currentvoltage properties of individual NW were measured by the conductive atomic force microscopy.The typical Schottky style photoconductive behavior was observed in the vertically aligned GaAs NW,and its photoresponsivity has been found to be much higher than that of the reported for single NW photodetector.Finally,a numerical model based on the experimental setup was established to simulate the photoelectric behavior of individual NW.The minority hole lifetime has been found to dominate the photoconductive current-voltage properties of NW under the positive sample bias,and can be derived from the quantitative fitting of experimental photo-IV curves.
We observe a power-dependent anticrossing of Walker spin-wave modes under microwave pumping when a ferrimagnet is placed in a microwave waveguide that does not support any discrete photon mode. We ...interpret this unexpected anticrossing as the generation of a pump-induced magnon mode that couples strongly to the Walker modes of the ferrimagnet. This anticrossing inherits an excellent tunability from the pump, which allows us to control the anticrossing via the pump power, frequency, and waveform. Further, we realize a remarkable functionality of this anticrossing, namely, a microwave frequency comb, in terms of the nonlinear interaction that mixes the pump and probe frequencies. Such a frequency comb originates from the magnetic dynamics and thereby does not suffer from the charge noise. The unveiled hybrid magnonics driven away from its equilibrium enriches the utilization of anticrossing for coherent information processing.
•The optical fiber coil with spool (OFCS) is a crucial tool for precise physics measurements.•To improve the seismic resistance of OFCSs in space applications, the vibration modes are thoroughly ...investigated through dynamic analysis, simulations, and experiments.•We establish a dynamic model of the OFCS based on the vibration transmission mechanism to characterize its vibration modes.•The vibration eigenfrequency and shapes are calculated under various conditions.•The experimental results validate the feasibility of the dynamic model and simulation, meanwhile, the discrepancies between the simulations and experiments are analyzed.•This study is the first of its kind to develop a comprehensive dynamic model for an OFCS, with simulations and experiments confirming its effectiveness.
The optical fiber coil with spool (OFCS) is a crucial tool for precise physics measurements. To improve the seismic resistance of OFCSs in space applications, the vibration modes are thoroughly investigated through dynamic analysis, simulations, and experiments. We establish a dynamic model of the OFCS based on the vibration transmission mechanism to characterize its vibration modes. The vibration eigenfrequency and shapes are calculated and simulated under various conditions. The experimental results validate the feasibility of the dynamic model and simulation, meanwhile, the discrepancies between the simulations and experiments are analyzed. This study is the first of its kind to develop a comprehensive dynamic model for an OFCS, with simulations and experiments confirming its effectiveness.
The on‐chip near‐infrared (NIR) lasing devices based on van der Waals (vdW) layered materials are highly desired owing to their widespread applications in optoelectronic communication, computing, and ...sensing. However, the single‐mode NIR lasing devices with superior performance based on vdW layered materials are hard to obtain because of complex and meticulous microcavity structure and the damage to layered materials during preparation. Here, a high‐quality NIR single‐mode lasing device in γ‐phase indium selenide (γ‐InSe) is achieved by using a transferrable planar microcavity. The single‐mode lasing devices based on distributed Bragg reflectors microcavity and super Tamm structure can be simply prepared with quality factors up to 5710 and 3526, respectively. And angle‐resolved spectra show that the lasing device has high directionality with divergence angle <5°. Moreover, the wavelength of lasing device can be tuned ≈30 nm by varying the cavity length via thickness control of γ‐InSe layer. These results not only suggest that γ‐InSe is a promising material for NIR lasing devices, but also present a simple and effective approach for preparing high‐quality lasing devices utilizing other vdW layered materials.
They achieve a high‐quality NIR single‐mode lasing device in γ‐phase indium selenide (γ‐InSe) by using a transferable planar microcavity. The single‐mode lasing devices based on distributed Bragg reflectors microcavity can be simply prepared with quality factors up to 5710 (this is the highest Q value of any vdW layered material NIR lasing devices demonstrated so far).
PDF
