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Azimuthal modulation of electromagnetically induced transparency using structured light
摘要： Recently a scheme has been proposed for detection of the structured light by measuring the transmission of a vortex beam through a cloud of cold rubidium atoms with energy levels of the Λ-type configuration [N. Radwell et al., Phys. Rev. Lett. 114, 123603 (2015)]. This enables observation of regions of spatially dependent electromagnetically induced transparency (EIT). Here we suggest another scenario for detection of the structured light by measuring the absorption profile of a weak nonvortex probe beam in a highly resonant five-level combined tripod and Λ (CTL) atom-light coupling setup. We demonstrate that due to the closed-loop structure of CTL scheme, the absorption of the probe beam depends on the azimuthal angle and orbital angular momentum (OAM) of the control vortex beams. This feature is missing in simple Λ or tripod schemes, as there is no loop in such atom-light couplings. One can identify different regions of spatially structured transparency through measuring the absorption of probe field under different configurations of structured control light.
关键词： orbital angular momentum,spatially dependent absorption,electromagnetically induced transparency,quantum interference,structured light
更新于2025-09-10 09:29:36
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A Fully Transparent, Flexible, Sensitive, and Visible-Blind Ultraviolet Sensor Based on Carbon Nanotube-Graphene Hybrid
摘要： Transparent and flexible UV sensors have attracted considerable attention for use in portable/wearable optoelectronic systems. Although UV sensors based on photoactive nanomaterials have been reported for such applications, achieving full transparency and flexibility remains a challenge because they still rely on opaque or brittle electrodes. Here, a fully transparent, flexible, and highly sensitive UV sensor based on 1D carbon nanotubes (CNTs)–2D graphene hybrid is demonstrated. Under UV illumination, oxygen molecules on the CNT surfaces are desorbed by photoinduced plasmon energy, leading to a significant decrease in hole concentration, and correspondingly an increase in the electrical resistance of CNT. The combination of CNT and graphene minimizes the effect of contact resistance and facilitates effective charge transfer between them without potential barrier, resulting in a high photoresponse, which is 30 times as high as that of Au-electrode-based CNT sensor. Simultaneously, CNT–graphene UV sensor shows remarkable transparency (over 80% at 550 nm) and outstanding mechanical flexibility without any significant change in electrical resistance for 500 cycles at a bending radius of 5.5 mm. The integration of CNT–graphene hybrid onto flexible substrates through scalable microfabrication is expected to provide exciting opportunities for the development of high performance, optically and mechanically invisible optoelectronic devices.
关键词： contact resistance,transparency,flexibility,carbon nanomaterials,ultraviolet monitoring
更新于2025-09-10 09:29:36
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Towards solution-processable, thermally robust, transparent polyimide-chain-end tethered organosilicate nanohybrids
摘要： The main challenge to developing future display substrates is to synthesize flexible substrate materials that also have excellent optical and thermal properties, and low thermal expansion number. In this study, a novel trifluoromethylated asymmetric aromatic diamine, 4-[[4-(4-amino-2-trifluoromethylphenoxy)phenyl]sulfonyl-3-(trifluoromethyl)]benzenamine (AFPSFB), was synthesized through nucleophilic substitution. Conventional two-step polycondensation of AFPSFB with commercially available tetracarboxylic dianhydrides enabled the fabrication of fully or semi-aromatic polyimides (PIs). The resulting PIs were highly soluble in polar aprotic solvents with good optical and thermal properties. Next, polyhedral oligomeric silsesquioxane containing an amine group (NH2-POSS) was reacted with the resulting soluble PI. All the PI-POSS nanohybrids displayed excellent optical properties, including high transparency (> 91% at 400 nm), low refractive index (< 1.5589), and very small birefringence (< 0.0025 at 637 nm). End-capping of the POSS and chemical bonding between the POSS and PIs significantly enhanced the thermal and electrical properties. The results provide useful information for designing molecular architectures for manufacturing high-performance flexible substrates in future display devices.
关键词： Organosilicate,Optical transparency,Dielectric constant,Thermal stability,Soluble polyimide
更新于2025-09-10 09:29:36
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Switching from EIT to EIA in a four-level N-type atomic system
摘要： We study the optical properties of a four-level N-type system theoretically for 87Rb atoms using density matrix formalism. Electromagnetically induced transparency and electromagnetically induced absorption (EIA) are two extensively studied two-photon coherence phenomena. EIA can be observed as a result of the transfer of coherence and transfer of population between the atomic levels. A narrow absorption is observed at the resonance frequency for moving atoms. Enhanced transmission and absorption lead to sub-luminal and super-luminal light propagation, respectively. It is observed that the third field in N-type system causes switching from transmission to absorption. We also discuss group index changes with coupling field strength.
关键词： N-type system,Optical switching,Electromagnetically induced absorption,Electromagnetically induced transparency
更新于2025-09-10 09:29:36
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[IEEE 2018 IEEE International Conference on Computational Electromagnetics (ICCEM) - Chengdu, China (2018.3.26-2018.3.28)] 2018 IEEE International Conference on Computational Electromagnetics (ICCEM) - Manipulating Propagation and Scattering of Microwave by Optically Transparent Metasurface
摘要： In this paper, metasurfaces with optical transparency is proposed to control either the propagation or the scattering of microwave. Specifically, we have designed a band-pass frequency selective surface (FSS) with a transmission window around 1.6 GHz and a coding metasurface for suppressing the backward scattering with broad working band from 7.8 to 15 GHz. The proposals provide new opportunities to tailor the microwave propagation and scattering with simultaneously high transmittance in visible frequencies, which could offer many benefits in practical uses, such as window and solar panel applications.
关键词： metasurface,microwave,optical transparency,FSS
更新于2025-09-10 09:29:36
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Electromagnetically Induced Transparency In Rydberg Atomic Medium
摘要： Due to possessing big principal quantum number, Rydberg atom has some unique properties, for example： its radiative lifetime is long, dipole moment is large, and interaction between atoms is strong and so on. These properties make one pay attention to Rydberg atoms. In this paper we investigate the effects of Rydberg dipole-dipole interactions on electromagnetically induced transparency (EIT) schemes and group velocity in three-level systems of ladder type, which provides theoretical foundation for exploring the linear and nonlinear characteristics of light in a Rydberg electromagnetically-induced-transparency medium.
关键词： group velocity,Rydberg atom,electromagnetically induced transparency,dipole-dipole interactions
更新于2025-09-09 09:28:46
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A Group-Delay-Based Sensor Using Active EIT-Like Effect With Double Sensing Applications
摘要： A high-sensitive microwave sensor based on the variation of group delay is presented in this paper. The sensor is designed by mimicking the concept of electromagnetically induced transparency (EIT). The EIT-like effect that applied in the microwave circuit can provide a narrow transmission window in the stop band, which also brings ultraslow group velocity. Combined with the utilization of active resonator, the quality factor and group delay of the sensor are significantly enhanced. The active resonator is actualized by appending an active feedback loop that couples with the split-ring resonator of the EIT-like structure. The group delay of the active EIT-like sensor is particularly sensitive to the tiny phase variation of the active feedback loop, which is adopted to the high-performance sensing functions. The active EIT-like sensor with double sensing applications in this paper was fabricated and tested. The sensitivity of the proposed sensor is 0.012 pF/ns and 0.03 mV/ns, respectively.
关键词： sensing,active resonator,electromagnetically induced transparency (EIT),Group delay
更新于2025-09-09 09:28:46
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Frequency Selected Coherent Optical Storage Based on Electromagnetically Induced Transparency in Rubidium Vapor
摘要： Storage capacity is a key requirement for multiplexed quantum memory in long-distance quantum communication and quantum calculation. The data exchange and processing of a quantum system would speed up, with the bene?t from the increasing storage capacity. In this paper, we demonstrate a frequency selected optical storage based on the electromagnetically induced transparency scheme in warm atomic vapor. Two probe pulses with di?erent frequencies could be stored and retrieved in di?erent memory cell individually, in which the memory cells are divided by the velocity of atomic motion in Doppler broadening atomic vapor. The theoretical predictions show that the frequency bandwidth of the proposed multiplexed optical storage is decided by the width of Doppler broadening and the frequency bandwidth of each memory cell is decided by the width of electromagnetically induced transparency window. The proposed frequency selected storage signi?cantly advances the pursuit of multiplexed optical memory and should have important applications in classical and quantum information processing.
关键词： electromagnetically induced transparency,storage,optical,Doppler broadening
更新于2025-09-09 09:28:46
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Acoustic and optical methods to infer water transparency at Time Series Station Spiekeroog, Wadden Sea
摘要： Water transparency is a primary indicator of optical water quality that is driven by suspended particulate and dissolved material. A data set from the operational Time Series Station Spiekeroog located at a tidal inlet of the Wadden Sea was used to perform (i) an inter-comparison of observations related to water transparency, (ii) correlation tests among these measured parameters, and (iii) to explore the utility of both acoustic and optical tools in monitoring water transparency. An Acoustic Doppler Current Profiler was used to derive the backscatter signal in the water column. Optical observations were collected using above-water hyperspectral radiometers and a submerged turbidity metre. Bio-fouling on the turbidity sensors optical windows resulted in measurement drift and abnormal values during quality control steps. We observed significant correlations between turbidity collected by the submerged metre and that derived from above-water radiometer observations. Turbidity from these sensors was also associated with the backscatter signal derived from the acoustic measurements. These findings suggest that both optical and acoustic measurements can be reasonable proxies of water transparency with the potential to mitigate gaps and increase data quality in long-time observation of marine environments.
关键词： optical measurements,acoustic backscatter,water transparency,Wadden Sea,turbidity
更新于2025-09-09 09:28:46
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Effect of the mechanical oscillator on the optical-response properties of an optical trimer system
摘要： We propose theoretically a four-mode coupled optomechanical system to explore the optical-response properties of an optical trimer system consisting of a passive cavity, a no-loss-gain cavity, and an active cavity coupled with a mechanical oscillator. In the study, the passive cavity is driven by an external laser so that the stability of the coupled system depends strongly on the gain-to-loss ratio and the photon tunneling between the adjacent cavities. We ?nd that in the regime near the stable-unstable critical point, the resonance absorption of the optical trimer system changes quickly with the increasing gain of the active cavity. In contrast, when the mechanical oscillator is coupled to the passive cavity, the center absorption peak is split and a phenomenon of optomechanically induced transparency appears. Consequently, two additional resonance peaks in the absorption pro?le are induced by the optomechanical coupling, which hinges on the tunneling between the optical cavities and also on the gain of the active cavity. The dependence of the width of the transparency window on the optomechanical coupling and the driving strength is also discussed in detail. The results obtained here indicate that the optical properties of the trimer system can be manipulated by coupling a mechanical oscillator to the system and therefore have a potential application in quantum optics and quantum information processing.
关键词： optomechanically induced transparency,quantum information processing,mechanical oscillator,quantum optics,optomechanical system,optical trimer system
更新于2025-09-09 09:28:46