- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Recent Advances in the Functional 2D Photonic and Optoelectronic Devices
摘要： 2D layered materials such as graphene, black phosphorus (BP), transition metal dichalcogenides (TMDCs), and their hybrid systems exhibit wide coverage of bandgaps, unique crystal structures, and the facile integration for potential applications in photonic and optoelectronic devices. In the recent two years, various 2D functional systems have been developed with novel optoelectronic properties, thereby expanding the functional applications. Beyond the speed, efficiency, or sensitivity, these 2D crystals can offer additional advantages and distinct applications in terms of spectrum range, polarization, intensity, and structural designs. The main contents here focus on optoelectronic and photonic devices with unique functional applications, especially mentioning areas as follows: long-wavelength photodetector, 2D polarization-sensitive photodetector, 2D optoelectronic memory, and 2D material-based optical modulator. For each section, the device design, performance, and operational principles are investigated and systematically discussed. Finally, the current research status is summarized and perspectives on possible applications in future are offered.
关键词： optical modulators,2D materials,polarization-sensitive photodetectors,long-wavelength photodetectors,optoelectronic memory
更新于2025-09-04 15:30:14
-
[IEEE 2018 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - Chengdu, China (2018.5.7-2018.5.11)] 2018 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - Multi-Color Coherent Smith-Purcell Radiation with Controllable Direction from 2D Rectangular Sub-Wavelength Hole Array
摘要： We proposed a multi-color Smith-Purcell radiation source with controllable emission direction by using a sheet free-electron beam to drive the two-dimensional rectangular sub-wavelength hole array. Each hole is an electromagnetic wave oscillating and radiating unit with specified frequencies. The coherent radiation is generated when the radiation from all units constructively interfere. By adjusting the arrangement of the sub-wavelength hole array, the coherent radiation direction could be steered in the three dimensional space.
关键词： terahertz source,sub-wavelength hole array,free-electron beam,Smith-Purcell radiation,coherent radiation
更新于2025-09-04 15:30:14
-
[IEEE 2018 2nd International Conference on Trends in Electronics and Informatics (ICOEI) - Tirunelveli, India (2018.5.11-2018.5.12)] 2018 2nd International Conference on Trends in Electronics and Informatics (ICOEI) - Improving the Performance of RoF System by FBG in a CS-DSB Based Wavelength Reuse Incorporating Coherent Detection and DSP
摘要： Improving the performance of a bidirectional radio over fiber (RoF) link by the use of fiber Bragg grating(FBG) in a carrier suppressed double sideband(CS-DSB)modulation based wavelength reuse incorporating coherent detection and signal processing unit like DSP is proposed. A comparison study is used to evaluate the performance improvement by the use of FBG. At the transmitter, a downstream optical signal containing optical sideband+carrier(OSSB+C)is generated and transmitted to base station via a single mode fiber(SMF). The signal received is reused at the base station, in two ways in order to study the performance improvement of RoF by the use of FBG. The optical single side band and carrier is separated by the help of a FBG. The carrier is further reused for the upstream signal transmission and the downstream signal can be recovered. The upstream signal is recovered using coherent detection along with DSP unit to avoid the noise due to the phase difference from the transmitter laser source and to eliminate the cross talk effects.
关键词： RoF,Wavelength Reuse,Phase noise cancellation (PNC),Digital signal processor (DSP)
更新于2025-09-04 15:30:14
-
SPR based fiber optic sensor using IMO thin film: towards wide wavelength tunability from visible to NIR
摘要： Due to existence of free electrons, conducting metal oxides (CMOs) such as indium molybdenum oxide, can support surface plasmon resonance (SPR) at the interface of CMO and the dielectric. This research provides first theoretically implementation of Indium molybdenum oxide (IMO) as plasmonic layer in SPR fiber optic sensor. We demonstrate how changing the oxygen contents during IMO layer deposition could tune the operational wavelength of sensing probe in a wide range from visible to NIR which has a great significance in many biological and chemical environmental applications. Moreover, sensitivity and figure of merit of the proposed sensor have been calculated and compared for IMO thin films prepared at different oxygen contents.
关键词： Surface plasmon resonance,Indium molybdenum oxide,Optical fiber sensors,Wide wavelength tunability,Figure of merit,Sensitivity
更新于2025-09-04 15:30:14
-
An entanglement-based wavelength-multiplexed quantum communication network
摘要： Quantum key distribution has reached the level of maturity required for deployment in real-world scenarios. It has previously been shown to operate alongside classical communication in the same telecommunication fibre and over long distances in fibre and in free-space links. Despite these advances, the practical applicability of quantum key distribution is curtailed by the fact that most implementations and protocols are limited to two communicating parties. Quantum networks scale the advantages of quantum key distribution protocols to more than two distant users. Here we present a fully connected quantum network architecture in which a single entangled photon source distributes quantum states to many users while minimizing the resources required for each. Further, it does so without sacrificing security or functionality relative to two-party communication schemes. We demonstrate the feasibility of our approach using a single source of bipartite polarization entanglement, which is multiplexed into 12 wavelength channels. Six states are then distributed between four users in a fully connected graph using only one fibre and one polarization analysis module per user. Because no adaptations of the entanglement source are required to add users, the network can readily be scaled to a large number of users, without requiring trust in the provider of the source. Unlike previous attempts at multi-user networks, which have been based on active optical switches and therefore limited to some duty cycle, our implementation is fully passive and thus has the potential for unprecedented quantum communication speeds.
关键词： Entanglement,Quantum key distribution,Quantum communication,Quantum networks,Wavelength-multiplexed
更新于2025-09-04 15:30:14
-
Femtosecond X-ray solution scattering reveals that bond formation mechanism of a gold trimer complex is independent of excitation wavelength
摘要： The [Au(CN)2]3 trimer in water experiences a strong van der Waals interaction between the d10 gold atoms due to large relativistic effect and can serve as an excellent model system to study the bond formation process in real time. The trimer in the ground state (S0) exists as a bent structure without the covalent bond between the gold atoms, and upon the laser excitation, one electron in the antibonding orbital goes to the bonding orbital, thereby inducing the formation of a covalent bond between gold atoms. This process has been studied by various time-resolved techniques, and most of the interpretation on the structure and dynamics converge except that the structure of the first intermediate (S1) has been debated due to different interpretations between femtosecond optical spectroscopy and femtosecond X-ray solution scattering. Recently, the excitation wavelength of 267 nm employed in our previous scattering experiment was suggested as the culprit for misinterpretation. Here, we revisited this issue by performing femtosecond X-ray solution scattering with 310 nm excitation and compared the results with our previous study employing 267 nm excitation. The data show that a linear S1 structure is formed within 500 fs regardless of excitation wavelength and the structural dynamics observed at both excitation wavelengths are identical to each other within experimental errors.
关键词： bond formation mechanism,Femtosecond X-ray solution scattering,gold trimer complex,excitation wavelength
更新于2025-09-04 15:30:14
-
[IEEE 2018 26th European Signal Processing Conference (EUSIPCO) - Roma, Italy (2018.9.3-2018.9.7)] 2018 26th European Signal Processing Conference (EUSIPCO) - Performance Evaluation of N O- Reference Image Quality Metrics for Visible Wavelength Iris Biometric Images
摘要： Image quality assessment plays an important role in iris recognition systems because the system performance is affected by low quality iris images. With the development of electronic color imaging, there are more and more researches about visible wavelength (VW) iris recognition. Compared to the near infrared iris images, using VW iris images acquired under unconstrained imaging conditions is a more challenging task for the iris recognition system. However, the number of quality assessment methods for VW iris images is limited. Therefore, it is interested to investigate whether existing no-reference image quality metrics (IQMs) which are designed for natural images can assess the quality of VW iris images. In this paper, we evaluate the performance of 15 selected no-reference IQMs on VW iris biometrics. The experimental results show that several IQMs can assess iris sample quality according to the system performance.
关键词： image quality assessment,visible wavelength iris,image based attributes,performance evaluation,multi-modality
更新于2025-09-04 15:30:14
-
PHOTONIC ANALYSIS OF SEMICONDUCTOR FIBONACCI SUPERLATTICES: PROPERTIES AND APPLICATIONS
摘要： In this paper, we theoretically study the phase treatment of re?ected waves in one-dimensional Fibonacci photonic quasicrystals composed of nano-scale fullerene and semiconductor layers. The dependence of the phase shift of re?ected waves for TE mode and TM mode on the wavelength and incident angle is calculated by using the theoretical model based on the transfer matrix method in the infrared wavelength region. In the band gaps of supposed structures, it is found that the phase shift of re?ected wave changes more slowly than within the transmission band gaps. Furthermore, the phase shift decreases with the incident angle increasing for TE mode, and increases with the incident angle increasing for TM mode. Also, for the supposed structures it is found that there is a band gap which is insensitive to the order of the Fibonacci sequence. These structures open a promising way to fabricate subwavelength tunable phase compensators, very compact wave plates and phase-sensitive interferometry for TE and TM waves.
关键词： Fibonacci photonic quasicrystals,TE mode,semiconductor layers,infrared wavelength region,fullerene,phase shift,transfer matrix method,TM mode
更新于2025-09-04 15:30:14
-
Design of liver functional reserve monitor based on three-wavelength from red light to IR
摘要： BACKGROUND: The preoperative evaluation of liver functional reserve is very important to determine the excision of liver lobe for the patients with liver cancer. There already exist many effective evaluation methods, but these ones have many disadvantages such as large trauma, complicated process and so on. OBJECTIVE: Therefore, it is essential to develop a fast, accurate and simple detection method of liver functional reserve for the practical application in the clinical engineering field. METHODS: According to the principle of spectrophotometry, this paper proposes a detection method of liver functional reserve based on three-wavelength from red light to infrared light (IR), in which the artery pulse, the vein pulse and the move of tissue are taken into account. RESULTS: By using photoelectric sensor technology and excreting experiment of indocyanine green, a minimally invasive, fast and simple testing equipment is designed in this paper. CONCLUSIONS: The testing result shows this equipment can greatly reduce the interference from human body and ambient, realize continuous and real-time detection of arterial degree of blood oxygen saturation and liver functional reserve.
关键词： Liver functional reserve,pulse blood oxygen,three-wavelength,photoelectric conversion
更新于2025-09-04 15:30:14
-
Design and investigation of a dual-layer grating coupler for efficient vertical fiber-chip coupling
摘要： A novel dual-layer grating coupler was designed for efficient vertical coupling between a single-mode fiber and silicon nanowires, with characteristics of polarization diversity and both wavelength bands of 1.3 and 1.55 μm. Theoretical analysis and two-dimensional finite-difference time-domain simulations were applied to verify the performance of the design. Optimized results show that the coupling efficiencies of a dual-port output of 41% (?3.87 dB) for transverse-electric polarization at 1.56 μm, 32.88% (?4.83 dB) for transverse-magnetic (TM) polarization at 1.58 μm, and 27.06% (?5.68 dB) for TM polarization at 1.32 μm can be achieved. Dual-layer Fabry–Perot resonance was also investigated for high coupling efficiency.
关键词： silicon nanowires,dual-layer grating coupler,vertical fiber-chip coupling,polarization diversity,wavelength bands
更新于2025-09-04 15:30:14