- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Linear and third order nonlinear optical properties of GaAs quantum dot in terahertz region
摘要： We study the electronic and optical properties of GaAs quantum dot embedded in Ga1-yAlyAs matrix. Using the effective mass approximation with the finite confinement potential the intraband energy levels and the wavefunctions are obtained. The linear and third order nonlinear optical properties, photoabsorption coefficient, refractive index change and susceptibility are studied for different dot radius in the terahertz region.
关键词： Quantum dots,Nanomaterials,Terahertz Radiation,Third order nonlinearity
更新于2025-09-16 10:30:52
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Silicate-germanates with the doubled mica-like layers [Pb(Si,Ge)O4]2-∞∞ in centrosymmetric Rb2Pb2[(Ge0.33Si0.67)2O7] and isolated in acentric, optically nonlinear Li6Pb2[(Ge0.4Si0.6)O4]2(OH)2
摘要： Silicate-germanates, Rb2Pb2[(Si0.67Ge0.33)2O7], P m1, and Li6Pb2[(Ge0.4Si0.6)O4]2(OH)2, P63mc, were synthesized in the multi-component hydrothermal systems. According to single crystal XR data, both structures contain identical mica-like layers [Pb(Ge,Si)O4]2- ∞∞, double or single, comprised of [(Si,Ge)O4]4--tetrahedra and umbrella-like groups [PbO3]4-: the latter play a unique role of (Si,Ge)-tetrahedra being of the same charge, dimension and the Pb-lone-pair as the forth apex. Predicted earlier polar ortho-silicate structure appears with small Li atom, while the centrosymmetric diortho-silicate structure type A2Pb2[B2O7] is stable with large A = K, Rb, Cs. Layers with {Li3O7}11- atomic clusters separate single tetrahedral layers. Under Nd:YAG laser illumination the powder of acentric Li,Pb-silicate-germanate yields intensive light of second harmonic. The maximum second harmonic intensity 10 times more in comparison with quartz standard is achieved in the powder with a grain size of about 20 μm. The space-averaged second-order nonlinear coefficient <d> = 1.1 pm/V. The comparably high optical nonlinearity is connected with the one-side directed umbrella-like polar units [PbO3]4- in polar structure of the Li,Pb-silicate-germanate.
关键词： materials design,structure,hydrothermal synthesis,lead-silicate-germanate,structure-properties relations,optical nonlinearity
更新于2025-09-16 10:30:52
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Nonlinear propagation of coupled surface TE and leaky TM electromagnetic waves
摘要： Propagation of the coupled electromagnetic wave, which is a superposition of TE surface and TM leaky waves, in the Goubau line (a perfectly conducting cylinder covered by a concentric dielectric layer) filled with nonlinear inhomogeneous medium is studied (if the permittivity is linear, the coupled wave does not exist). Nonlinear coupled TE–TM wave is characterised by two (independent) frequencies and two (coupled) propagation constants (propagation constants). The physical problem is reduced to a nonlinear two-parameter transmission eigenvalue problem for Maxwell’s equations. Existence of coupled TE–TM waves is proved. Intervals of localisation of propagation constants are found.
关键词： nonlinear waveguide,Nonlinear coupled TE–TM waves,Kerr nonlinearity,Maxwell’s equations,two-parameter eigenvalue problem,coupled propagation constants
更新于2025-09-16 10:30:52
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[IEEE 2019 International Vacuum Electronics Conference (IVEC) - Busan, Korea (South) (2019.4.28-2019.5.1)] 2019 International Vacuum Electronics Conference (IVEC) - Notice of Removal: Compact Waveguide Coupler with Broadband and High Coupling Flatness
摘要： In this paper, we investigate the properties of transmission links amplified by phase-sensitive amplifiers (PSAs). Using an analytic description, we explain the principles enabling improved sensitivity compared to conventional links amplified by phase-insensitive amplifiers (PIAs) and mitigation of nonlinear transmission distortions. We demonstrate these features using numerical simulations, and in particular, we show the possibility of efficiently mitigating both self-phase modulation (SPM)-induced distortions and nonlinear phase noise (NLPN) if the link dispersion map is optimized. The properties of the noise on signal and idler are important and to enable NLPN mitigation, the noise must be correlated at the link input. We investigate the role of the dispersion map in detail and show that in a link with standard single mode fiber (SSMF) the optimum dispersion map for efficient nonlinearity mitigation corresponds to precompensation of an amount equal to the effective loss length. Furthermore, we experimentally demonstrate both improved sensitivity and mitigation of nonlinearities in a 105 km PSA-amplified link transmitting 10 GBd 16-ary quadrature amplitude modulation (16QAM) data. We measure a combined effect allowing for more than 12 dB larger span loss in a PSA-amplified link compared to a conventional PIA-amplified link to reach the same bit error ratio (BER) of 1 × 10?3.
关键词： Fiber nonlinearity mitigation,phase-conjugated twin waves,fiber optical parametric amplifiers (FOPAs),optical amplifiers,phase-sensitive amplifiers (PSAs),optical fiber communication
更新于2025-09-16 10:30:52
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[IEEE 2019 International Conference on Electrical Engineering and Informatics (ICEEI) - Bandung, Indonesia (2019.7.9-2019.7.10)] 2019 International Conference on Electrical Engineering and Informatics (ICEEI) - Rooftop Photovoltaic Hosting Capacity Assessment: A Case Study of Rural Distribution Grids in Yogyakarta, Indonesia
摘要： In this paper, we investigate the properties of transmission links amplified by phase-sensitive amplifiers (PSAs). Using an analytic description, we explain the principles enabling improved sensitivity compared to conventional links amplified by phase-insensitive amplifiers (PIAs) and mitigation of nonlinear transmission distortions. We demonstrate these features using numerical simulations, and in particular, we show the possibility of efficiently mitigating both self-phase modulation (SPM)-induced distortions and nonlinear phase noise (NLPN) if the link dispersion map is optimized. The properties of the noise on signal and idler are important and to enable NLPN mitigation, the noise must be correlated at the link input. We investigate the role of the dispersion map in detail and show that in a link with standard single mode fiber (SSMF) the optimum dispersion map for efficient nonlinearity mitigation corresponds to precompensation of an amount equal to the effective loss length. Furthermore, we experimentally demonstrate both improved sensitivity and mitigation of nonlinearities in a 105 km PSA-amplified link transmitting 10 GBd 16-ary quadrature amplitude modulation (16QAM) data. We measure a combined effect allowing for more than 12 dB larger span loss in a PSA-amplified link compared to a conventional PIA-amplified link to reach the same bit error ratio (BER) of 1 × 10?3.
关键词： Fiber nonlinearity mitigation,phase-conjugated twin waves,fiber optical parametric amplifiers (FOPAs),optical amplifiers,phase-sensitive amplifiers (PSAs),optical fiber communication
更新于2025-09-16 10:30:52
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[IEEE 2019 IEEE International Conference on Imaging Systems and Techniques (IST) - Abu Dhabi, United Arab Emirates (2019.12.9-2019.12.10)] 2019 IEEE International Conference on Imaging Systems and Techniques (IST) - A Multi-frequency WMS Method for Tunable Diode Laser Absorption Spectroscopy Tomography
摘要： In this paper, we investigate the properties of transmission links amplified by phase-sensitive amplifiers (PSAs). Using an analytic description, we explain the principles enabling improved sensitivity compared to conventional links amplified by phase-insensitive amplifiers (PIAs) and mitigation of nonlinear transmission distortions. We demonstrate these features using numerical simulations, and in particular, we show the possibility of efficiently mitigating both self-phase modulation (SPM)-induced distortions and nonlinear phase noise (NLPN) if the link dispersion map is optimized. The properties of the noise on signal and idler are important and to enable NLPN mitigation, the noise must be correlated at the link input. We investigate the role of the dispersion map in detail and show that in a link with standard single mode fiber (SSMF) the optimum dispersion map for efficient nonlinearity mitigation corresponds to precompensation of an amount equal to the effective loss length. Furthermore, we experimentally demonstrate both improved sensitivity and mitigation of nonlinearities in a 105 km PSA-amplified link transmitting 10 GBd 16-ary quadrature amplitude modulation (16QAM) data. We measure a combined effect allowing for more than 12 dB larger span loss in a PSA-amplified link compared to a conventional PIA-amplified link to reach the same bit error ratio (BER) of 1 × 10?3.
关键词： Fiber nonlinearity mitigation,phase-conjugated twin waves,fiber optical parametric amplifiers (FOPAs),optical amplifiers,phase-sensitive amplifiers (PSAs),optical fiber communication
更新于2025-09-16 10:30:52
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Probing Vacuum Polarization Effects with High-Intensity Lasers
摘要： These notes provide a pedagogical introduction to the theoretical study of vacuum polarization effects in strong electromagnetic fields as provided by state-of-the-art high-intensity lasers. Quantum vacuum fluctuations give rise to effective couplings between electromagnetic fields, thereby supplementing Maxwell’s linear theory of classical electrodynamics with nonlinearities. Resorting to a simplified laser pulse model, allowing for explicit analytical insights, we demonstrate how to efficiently analyze all-optical signatures of these effective interactions in high-intensity laser experiments. Moreover, we highlight several key features relevant for the accurate planning and quantitative theoretical analysis of quantum vacuum nonlinearities in the collision of high-intensity laser pulses.
关键词： external-field QED,quantum vacuum nonlinearity,all-optical signatures
更新于2025-09-16 10:30:52
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Third-order nonlinear optical response of Yb:YAG ceramics under femtosecond laser irradiation
摘要： Transparent ceramic laser materials, as an important alternate of traditional laser gain medium materials, have aroused much attention for their excellent performance. Here, we investigated the third-order nonlinear susceptibility of high quality transparent Ytterbium-doped Yttrium Aluminium Garnet (Yb:YAG) ceramics. Under an ultrafast femtosecond laser irradiation, we experimentally demonstrated the nonlinear optical limiting and self-focusing behaviors of Yb:YAG ceramic by Z-scan method at 800 nm. It was found that Yb:YAG ceramics exhibit a relatively small nonlinear refractive index (~3.8 × 10?20 m2/W) which exerts little dependence on the Yb3+ doping concentration and laser intensity. This work could illustrate the application potential of transparent ceramic under high-power condition and can also provide useful design guidelines for high power ceramic laser system.
关键词： Third-order optical nonlinearity,Z-scan,Nonlinear refractive index,Yb:YAG ceramics
更新于2025-09-16 10:30:52
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[IEEE 2019 International Conference on Advanced Electrical Engineering (ICAEE) - Algiers, Algeria (2019.11.19-2019.11.21)] 2019 International Conference on Advanced Electrical Engineering (ICAEE) - Study of Hybrid Photovoltaic/Thermal Collector Provided With Finned Metal Plates: A Numerical Investigation under Real Operating Conditions
摘要： This paper investigates at the example of bathymetry how much an application can profit from comprehensive characterizations required for an improved calibration of data from a state-of-the-art commercial hyperspectral sensor. A NEO HySpex VNIR-1600 sensor is used for this paper, and the improvements are based on measurements of sensor properties not covered by the manufacturer, in particular, detector nonlinearity and stray light. This additional knowledge about the instrument is used to implement corrections for nonlinearity, stray light, spectral smile distortion and nonuniform spectral bandwidth and to base the radiometric calibration on a SI-traceable radiance standard. Bathymetry is retrieved from a data take from the lake Starnberg using WASI-2D. The results using the original and improved calibration procedures are compared with ground reference data, with an emphasis on the effect of stray-light correction. For our instrument, stray-light biases the detector response from 416–500 nm up to 8% and from 700–760 nm up to 5%. Stray-light-induced errors affect bathymetry mainly in water deeper than Secchi depth, whereas in shallower water, the dominant error source is the calibration accuracy of the light source used for radiometric calibration. Stray-light correction reduced the systematic error of water depth by 19% from Secchi depth to three times Secchi depth, whereas the relative standard deviation remained stable at 5%.
关键词： stray light,Bathymetry,calibration,nonlinearity,remote sensing,hyperspectral,imaging spectrometer
更新于2025-09-16 10:30:52
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Advanced DSP for Coherent Optical Fiber Communication
摘要： In this paper, we provide an overview of recent progress on advanced digital signal processing (DSP) techniques for high-capacity long-haul coherent optical fiber transmission systems. Not only the linear impairments existing in optical transmission links need to be compensated, but also, the nonlinear impairments require proper algorithms for mitigation because they become major limiting factors for long-haul large-capacity optical transmission systems. Besides the time domain equalization (TDE), the frequency domain equalization (FDE) DSP also provides a similar performance, with a much-reduced computational complexity. Advanced DSP also plays an important role for the realization of space division multiplexing (SDM). SDM techniques have been developed recently to enhance the system capacity by at least one order of magnitude. Some impressive results have been reported and have outperformed the nonlinear Shannon limit of the single-mode fiber (SMF). SDM introduces the space dimension to the optical fiber communication. The few-mode fiber (FMF) and multi-core fiber (MCF) have been manufactured for novel multiplexing techniques such as mode-division multiplexing (MDM) and multi-core multiplexing (MCM). Each mode or core can be considered as an independent degree of freedom, but unfortunately, signals will suffer serious coupling during the propagation. Multi-input–multi-output (MIMO) DSP can equalize the signal coupling and makes SDM transmission feasible. The machine learning (ML) technique has attracted worldwide attention and has been explored for advanced DSP. In this paper, we firstly introduce the principle and scheme of coherent detection to explain why the DSP techniques can compensate for transmission impairments. Then corresponding technologies related to the DSP, such as nonlinearity compensation, FDE, SDM and ML will be discussed. Relevant techniques will be analyzed, and representational results and experimental verifications will be demonstrated. In the end, a brief conclusion and perspective will be provided.
关键词： coherent detection,neural network,space division multiplexing,digital signal processing,nonlinearity compensation,machine learning,optical fiber communication,equalization
更新于2025-09-16 10:30:52