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AIP Conference Proceedings [AIP Publishing 15th International Conference on Concentrator Photovoltaic Systems (CPV-15) - Fes, Morocco (25–27 March 2019)] 15th International Conference on Concentrator Photovoltaic Systems (CPV-15) - Optimum design of V-trough solar concentrator for photovoltaic applications
摘要： This paper presents a novel design of V-trough Solar Concentrator (VSC) for low concentrator photovoltaic (CPV) applications. The conventional VSC design comprises of two flat reflectors slanted by an angle and attached to a PV module. The maximum reported concentration ratio (CR) and optical efficiency (OE) of this concentrator are 2x and 89.91%, respectively. This paper demonstrates the process of improving the VSC. The geometrical and optical performance of the conventional VSC were optimized by the theoretical image technique. The experimental CR and OE are increased by 43.50% and 4.32%, respectively. Then, a crossed V-trough design “Pyramid” is suggested to increase the concentrated radiation. Pyramid concentrator boosted the CR, but the OE is dropped. Eventually, a new VSC geometry is proposed and resulted in CR of 4.70x and OE of 91.83%. The new design demonstrates the possibility of obtaining the same CR using a smaller reflector area than conventional and pyramid V-trough configurations, leading to a reduction in production cost. The results show the potential to further improve this type of solar concentrator for photovoltaic applications.
关键词： V-trough Solar Concentrator,solar concentrator design,concentration ratio,photovoltaic applications,optical efficiency
更新于2025-09-11 14:15:04
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Bioelectrochemical Interface Engineering || Quantum Dots for Bioelectrochemical Applications
摘要： In this chapter, the structure, characteristics, and synthesis processes of QDs were summarized. The most common electrochemical methods for QDs were also represented by reviewing their potential applications in biosensor technology. Many specific applications have been realized by utilizing the unique characteristics of QDs. However, their limited commercial availability; requirements of demanding synthesis procedures, analysis of multicomponent complex samples, and in situ analysis; and lack of validation with real samples are other disadvantage of QDs. The design of QD-based biosensors is also complicated due to limitedly defined redox behavior of nanocrystals resulting in difficulty with probing their redox levels. Therefore, extensive investigations are needed on the redox properties of QDs, despite having a large amount of literature on their synthesis, properties, and applications. The interactions between the system parameters can be clarified by using the mathematical models. To solve the model equations analytically, it is introduced to equivalent systems having identical spectra and wave functions, and these forms have to satisfy the solvability conditions. 3D QDs can be modeled by an ODE accurately, when the dimension of the cross section is very small and the energy levels are low. To obtain high accuracy of the effective mass approximation model, sizes of the QDs should be 10–20 nm. Optimum design problems for QD systems generally have discrete search spaces and involve highly nonlinear terms. Therefore, the selection of any traditional optimization methods to solve optimization problems is not appropriate. In these circumstances, it is useful to perform modern optimization algorithms such as the GA, DE, and SA methods. By incorporating mathematical models and optimization approximations to QD-based bioloelectrochemical systems, their performances will excel far beyond the current state in the near future.
关键词： Optimization Algorithms,Mathematical Models,Bioelectrochemical Applications,Electrochemical Methods,Biosensor Technology,Quantum Dots
更新于2025-09-11 14:15:04
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Accelerating the Screening of Perovskite Compositions for Photovoltaic Applications through High‐Throughput Inkjet Printing
摘要： The exploration and optimization of numerous mixed perovskite compositions are causing a strong demand for high-throughput synthesis. Nevertheless high-throughput fabrication of perovskite films with representative film properties, which can efficiently screen the perovskite compositions for photovoltaic applications, has rarely been explored. A high-throughput inkjet printing approach that can automatically fabricate perovskite films with various compositions with high reproducibility and high speed is developed. The automatic sequential printing of four precursors forms 25 mixed films in a fast and reproducible manner. The obtained bandgaps, photoluminescence (PL) peak positions, and PL lifetimes allow for the efficient screening of perovskite compositions for photovoltaic applications. To exemplify this concept, among 25 tested films, two compositions CH3NH3PbBr0.75I2.25 (MA) and (HC(NH2)2)0.75(CH3NH3)0.25PbBr0.75I2.25 (FA0.75MA0.25) with a long (237 ns) and short (49.0 ns) PL lifetime, respectively, are screened out for device investigations. As expected, the MA-based device exhibits a much higher efficiency (19.0%) than that (15.3%) of the FA0.75MA0.25 counterpart. This efficiency improvement is mainly ascribed to a smaller dark saturate current density, a lower level of energetic disorder, more efficient charge transfer and decreased charge recombination losses, which are consistent with the much longer PL lifetime in the database.
关键词： perovskites,photovoltaic applications,inkjet printing,high throughput fabrication
更新于2025-09-11 14:15:04
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Micro‐ and Nanolasers
摘要： A laser is a device that emits strong coherent light through a process of light amplification by stimulated emission of radiation. The theoretical foundation for the laser was established by Albert Einstein theorizing on the existence of stimulated emission in 1916. The first laser was built by Theodore Maiman in 1960 based on the theoretical work of Charles Townes and Arthur Schawlow. The invention and continuous development of the laser has revolutionized science, technology, and industry. Miniaturization of lasers has been promoting the development and application of laser technology. For example, compact semiconductor lasers have become an integral part of our everyday life. With the development of micro- and nanofabrication technology, including both top-down and bottom-up techniques, the dimensions of lasers have been shrunk down to micro- and nanoscale. With an unprecedented ability to deliver intense coherent light at (sub)wavelength scale, such micro- and nanolasers are promising to trigger the next revolution in the laser and related fields. Indeed, the micro- and nanolasers are or will be unlocking their potential in photonic and optoelectronic applications, such as chemical and biological sensing, laser display and holography, on-chip optical communication and processing, and so on.
关键词： micro- and nanolasers,on-chip optical communication and processing,chemical and biological sensing,photonic and optoelectronic applications,laser display and holography
更新于2025-09-11 14:15:04
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Carbon nanotube: Controlled synthesis determines its future; 碳纳米管: 可控制备决定未来;
摘要： Carbon nanotubes (CNTs) have received broad attention in the past decades due to their excellent physical and chemical properties and thus been regarded as a powerful candidate for future star-materials. Although various CNT products and their related applications have been demonstrated recently, their performance can hardly meet the researchers’ expectations compared with their theoretical properties. The current predicament is caused by the immature synthesis method, including the basic science and the producing technology. As the synthesis with controlled structures determines its future, this review summarizes the progress on the basic research and industrialization of CNTs in the past decades, including the fine structure control, aggregation status design and scale-up production, and further points out the way for the future development of CNTs combining with specific applications.
关键词： applications,carbon nanotubes,scale-up synthesis,structure-controlled synthesis
更新于2025-09-11 14:15:04
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Rational Molecular Design towards NIR Absorption; Efficient Diketopyrrolopyrrole Derivatives for Organic Solar Cells and Photothermal Therapy
摘要： After the development of diketopyrrolopyrrole (DPP) in 1974, its derivatives have been widely explored for optoelectronic applications. In this review we discuss various donor/acceptor functionalized DPPs which are recently published and systematically compared their properties. The modification of donor functionalized DPP to tetracyanobutadiene (TCBD) bridged derivatives with improved acceptor strength, absorption towards near infra-red region have shown some exciting advancement in non-fullerene acceptors for organic solar cells and as therapeutic agents in photothermal therapy are also described. The optoelectronic properties in relation to structural changes such as change of end capping groups, donor–acceptor moieties, aromatic moiety in DPP core and number of DPP units in the molecular structure are discussed. We are expecting that the current review will provide guidelines for the exploration of new DPP based efficient materials for photovoltaic and biomedical applications.
关键词： diketopyrrolopyrrole,optoelectronic applications,photothermal therapy,organic solar cells,NIR absorption
更新于2025-09-11 14:15:04
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Ge/YbF <sub/>3</sub> and ZnS/YbF <sub/>3</sub> Thin-Film Combinations Open New Perspectives in Production of Broadband Optics for Mid-Infrared Laser Applications
摘要： Recently, the mid-infrared (MIR) spectral region has become more and more interesting for bio-medical laser applications since large organic molecules exhibit their fundamental vibrational and rotational modes in this range[1]. In this rapidly developing research area, high-quality optical interference coatings are highly demanded. In many laser systems (see, for instance [2]), it is required to separate initial high-power near-infrared beams originated from a driving laser from lower power MIR components emerged in a nonlinear crystal through a nonlinear process (for example, frequency difference generation). The corresponding multilayer dichroic filters reflecting the radiation in the near-infrared range and transmitting the MIR radiation are required. The coatings exhibit desired reflectance and phase in a near-infrared range and high transmittance in a required MIR region. The acceptable levels of reflectance and transmittance, width of the high-reflectance and high-transmittance ranges, polarization states as well as the angle of incidence are dependent on the laser setup. Along with the specified spectral performance, non-optical properties such as good adhesion, low mechanical stress, thermal stability, are of outmost importance. Low stress is crucial in order not to deform the laser beam wave front of the entire laser system and to avoid thermal lensing. Therefore, the choice of the appropriate evaporation materials and optimization of the high-vacuum deposition processes on the one hand and selection of optimal design solutions on the other hand are key elements in development of advanced multilayer optics for laser systems.
关键词： laser applications,dichroic filters,Ge/YbF3,ZnS/YbF3,optical interference coatings,mid-infrared
更新于2025-09-11 14:15:04
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Pure-Quartic Solitons from a Dispersion Managed Fibre Laser
摘要： In optical fibre resonators, the balance between anomalous quadratic dispersion and self-phase modulation (SPM) gives rise to optical solitons [1]. These pulses have made a significant impact in a wide range of photonic applications including telecommunications and lasers. However, these conventional soliton-based lasers can only deliver modest pulse energy due to the appearance of Kelly sidebands arising from periodical perturbations in the cavity [2] and a fixed energy-width scaling. Recently, a new class of soliton, arising from the balance of anomalous quartic dispersion and SPM, called pure-quartic soliton (PQS), were observed in a dispersion engineered photonic crystal waveguide [3]. PQSs have huge potential for generating ultrashort pulses with high energy due to their generalized area theorem (E ~ 1/(cid:507)(cid:306)3), however they are yet to be observed in fibre platforms [4]. Here we report on the generation of PQS pulses from a passively mode-locked fibre laser incorporating a programmable spectral pulse-shaper that induces a dominant quartic net cavity dispersion. We find that the spectral profile of the generated pulses are in good agreement with the spectral shape of PQSs [3]. We also observe spectral sidebands in this quartic-dispersion cavity, in analogy to the conventional soliton case [2], and find that their positions are in excellent agreement with analytic predictions. These are strong evidences of a novel type of mode-locked laser, the PQS laser, which has the potential to reach dramatically higher energies at short pulse durations than its conventional soliton counterpart [3,4].
关键词： dispersion managed fibre laser,pure-quartic solitons,optical solitons,photonic applications,self-phase modulation
更新于2025-09-11 14:15:04
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Efficient Er and Nd:Ti:LiNbO <sub/>3</sub> Ridge Waveguide Lasers for the Development of Mid Infrared Sources
摘要： The ferroelectric crystal lithium niobate (LiNbO3) is an attractive material for a variety of photonics applications due to its excellent electro-optic and nonlinear properties. Another benefit of rare-earth doped LiNbO3 is the easy implementation of low-loss waveguides leading to the development of waveguide amplifiers as well as waveguide lasers. In the past, a great deal of attention was attracted to the development of optically pumped Er3+- and Nd3+-doped LiNbO3 waveguide lasers emitting around the 1.5 μm telecom wavelength range and 1.08 μm, respectively. Up to date, Er- and Nd-doped LiNbO3 channel waveguide lasers with slope efficiencies up to 30 % [1] and 40 % [2], respectively, have been reported. However, a further improvement of the laser performance can be achieved by using a ridge waveguide geometry due to the smaller mode fields and improved overlap of modes at different wavelengths as well as the reduction of photorefractive damage. In this work, we report on our novel fabrication method for the development of highly efficient Er: and Nd:Ti:LiNbO3 ridge waveguide amplifiers and lasers [3,4]. To improve the amplifier/laser performance a fabrication technique comprised of ridge definition by diamond blade dicing followed by three-side Er/Nd/Ti deposition and in-diffusion (Fig. 1a) was developed and refined allowing higher Er/Nd doping concentrations and overlap of Er/Nd diffusion profiles with guided modes. An internal gain of 3.0 dB/cm has been measured in 4.6 cm long Er:Ti:LiNbO3 ridge waveguides for a coupled pump power of 200 mW at 1486 nm [3]. Utilizing this high internal gain, we achieved efficient lasing with a slope efficiency of 33 % at 1561 nm (see Fig. 1b) [3]. Furthermore, we demonstrated a Nd:Ti:LiNbO3 ridge waveguide laser with a slope efficiency of 34 % at a wavelength of 1084.7 nm pumped by a Ti:Sapphire laser emitting at 814 nm (see Fig. 1b) [4]. Due to improved photorefractive damage resistance by indium tin oxide (ITO) coating we achieved stable laser operation with a maximum output power of 108 mW for a coupled pump power of 402 mW corresponding to an intensity of ~490 kW/cm2 [4]. Recently, a novel method to achieve local periodic poling of Ti-diffused ridge waveguides in zx-cut LiNbO3 has been demonstrated [5]. In contrast to previous approaches, this method for periodic poling allows an optimization of the ridge waveguide geometry for nonlinear optics applications such as quasi-phase-matched (QPM) difference frequency generation (DFG). The ability to develop highly efficient Er- and Nd-doped ridge waveguide lasers in LiNbO3 and to achieve local QPM allows for the development of efficient hybrid optical devices in the same ridge waveguide emitting in the mid-infrared suitable for applications such as gas sensing.
关键词： Nd-doped,ridge waveguide lasers,lithium niobate,photonics applications,Er-doped
更新于2025-09-11 14:15:04
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Non-Linear Propagation of Ultrashort Mid-IR Pulses
摘要： Many atmospheric applications such as free-space communication or spectroscopy require targeted delivery of high-energy ultrashort pulses with a good beam quality. Often atmospheric turbulences complicate this task, causing random variations of the refractive index and resulting in fluctuations of light intensity on the target. Propagation of light in filamentation regime, when intensity is clamped, to a certain extent helps to overtake this problem, but brings ionization-related problems, such as energy loss, temporal pulse splitting, etc. Moreover, maximum peak power (cid:1842)(cid:3043)(cid:3032)(cid:3028)(cid:3038), which can be delivered in a single filament is limited to about ten critical powers of self-focusing (cid:1842)(cid:3030)(cid:3045)(cid:3036)(cid:3047), after which multiple filamentation and hence small-scale beam distortions take place. In the case of Ti:Sapphire drivers delivering 40-fs, 800-nm pulses, the energy in a single filament in air doesn’t exceed 1 mJ, unless special conditions are applied [1]. However, since (cid:1842)(cid:3030)(cid:3045)(cid:3036)(cid:3047)~(cid:2019)(cid:2870) ((cid:2019) is the driver wavelength), essentially more energy can be deposited in a single filament driven by 3.9-μm pulses [2]. Furthermore, mid-IR spectral range is beneficial in virtue of lower ionization rates and higher resistance to modulation instabilities and scattering by natural atmospheric obstacles, such as water droplets [3]. Finally, a unique combination of high atmospheric transparency and anomalous dispersion of air between 3.6-4.2 μm promote an opportunity for a lossless high-energy ultrashort pulse delivery and simultaneous solitonic self-compression [4]. However, multiple molecular resonances responsible for the anomalous dispersion also complicate filamentation dynamics by adding a new channel of energy loss, namely nonlinear enhanced absorption losses [2,5], when mainly stimulated rotational Raman scattering (SRRS) governs spectral dynamics dominated by an essential spectral redshift and immediate absorption of newly generated spectral components by CO2, having vibrational resonance in the vicinity of 4.2 μm. Due to this non-linearly enhanced absorption up to 50% of energy can be lost over several meters of propagation of 30 mJ 130-fs pulses [2]. However, since the intrapulse SRRS is sensitive to a temporal spacing between spectral components, pre-chirping of drivers pulses can help to reduce and control the energy loss. Moreover, we have demonstrated, that a proper choice of the chirp can also lead to ~5-fold self-compression in time and postponed onset of filamentation in space, what fulfils a goal of targeted high-energy ultrashort pulse delivery.
关键词： Ultrashort mid-IR pulses,filamentation,solitonic self-compression,nonlinear propagation,atmospheric applications
更新于2025-09-11 14:15:04