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Frequency characteristics of a GPL-reinforced composite microdisk coupled with a piezoelectric layer
摘要： This is the ?rst research on the frequency analysis of a graphene nanoplatelet composite (GPLRC) microdisk in the framework of a numerical-based generalized differential quadrature method. The stresses and strains are obtained using the higher-order shear deformable theory. Rule of mixture is employed to obtain varying mass density, thermal expansion, and Poisson’s ratio, while module of elasticity is computed by modi?ed Halpin–Tsai model. Governing equations and boundary conditions of the GPLRC microdisk covered with piezoelectric layer are obtained by implementing Hamilton’s principle. Regarding perfect bonding between the piezoelectric layer and core, the compatibility conditions are derived. In addition, due to the existence of piezoelectric layer, Maxwell’s equation is derived. The results show that outer-to-inner ratio of radius (Ro/Ri), ratios of length scale and nonlocal to thickness (l/h and μ/h), ratio of piezoelectric to core thickness (hp/h), applied voltage, and GPL weight fraction (gGPL) have signi?cant in?uence on the frequency characteristics of the GPLRC microdisk. Another important consequence is that in addition to the nonlinear indirect effects of applied voltage on the natural frequency of the GPLRC microdisk covered with piezoelectric for each speci?c value of Ro/Ri, the impact of the Ro/Ri on the natural frequency is indirect. A useful suggestion of this research is that, for designing the GPLRC circular microplate at the low value of the Ro/Ri should be more attention to the gGPL and Ro/Ri, simultaneously.
关键词： Higher-order shear deformable theory,Halpin–Tsai model,Microdisk,Piezoelectric layer,Hamilton’s principle,Maxwell’s equation,Generalized differential quadrature method,Frequency analysis,Graphene nanoplatelet composite (GPLRC)
更新于2025-09-19 17:13:59
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[IEEE 2019 International Topical Meeting on Microwave Photonics (MWP) - Ottawa, ON, Canada (2019.10.7-2019.10.10)] 2019 International Topical Meeting on Microwave Photonics (MWP) - Widely Tunable Parity-Time-Symmetric Optoelectronic Oscillator Based on a Silicon Microdisk Resonator
摘要： A widely frequency-tunable parity-time (PT)-symmetric optoelectronic oscillator (OEO) based on a silicon microdisk resonator (MDR) is proposed and experimentally demonstrated. In the proposed OEO, two mutually coupled optoelectronic loops having an identical geometry with one having a gain and the other a loss, which are equal in magnitude, light implemented by employing the reciprocity of are propagation in an MDR, to form a PT-symmetric OEO. Thanks to the PT symmetry, single-frequency oscillation with low phase noise is implemented. The tuning of the frequency is realized by thermally tuning the MDR. The proposed OEO is demonstrated experimentally. A wide frequency tunable range from 2 to 12 GHz is realized. The phase noise is measured to be -105 dBc/Hz at a 10 kHz frequency offset, which can be further reduced if the loop length is increased.
关键词： Silicon photonics,Optoelectronic oscillator (OEO),Parity-time symmetric,Microwave photonic bandpass filter,Microwave photonics,microdisk resonator
更新于2025-09-16 10:30:52
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Record Low Threshold Current Density in Quantum Dot Microdisk Laser
摘要： We demonstrate a record low threshold current density of 250 A/cm2 in a quantum dot microdisk laser with a 31-μ m diameter operating at room temperature in continuous wave regime without temperature stabilization. This low threshold current density is very close to the transparency current density estimated in broad-area edge-emitting lasers made of the same epitaxial wafer.
关键词： threshold current density,quantum dots,microdisk laser
更新于2025-09-16 10:30:52
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The Use of Microdisk Lasers Based on InAs/InGaAs Quantum Dots in Biodetection
摘要： It is demonstrated that microdisk lasers about 10 μ m in diameter with an active region based on InAs/InGaAs quantum dots synthesized on GaAs substrates can be used for biodetection. Chimeric monoclonal antibodies against the CD20 protein that are covalently attached to the surface of microdisk lasers operating in an aqueous medium under optical pumping and room temperature were used as detectable objects. It is shown that the addition of secondary antibodies leads to an increase in the threshold power of laser generation, as well as to an increase in the full width at half maximum (FWHM) of the resonance laser line.
关键词： biosensor,microdisk laser,semiconductor laser,photoluminescence,quantum dots
更新于2025-09-16 10:30:52
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Spectral Modulation of Optofluidic Coupled-Microdisk Lasers in Aqueous Media
摘要： We present the spectral modulation of an opto?uidic microdisk device and investigate the mechanism and characteristics of the microdisk laser in aqueous media. The opto?uidic microdisk device combines a solid-state dye-doped polymer microdisk with a micro?uidic channel device, whose optical ?eld can interact with the aqueous media. Interesting phenomena, such as mode splitting and single-mode lasing in the laser spectrum, can be observed in two coupled microdisks under the pump laser. We modulated the spectra by changing the gap of the two coupled microdisks, the refractive indices of the aqueous media, and the position of a pump light, namely, selective pumping schemes. This opto?uidic microlaser provides a method to modulate the laser spectra precisely and ?exibly, which will help to further understand spectral properties of coupled microcavity laser systems and develop potential applications in photobiology and photomedicine.
关键词： coupled microdisk,opto?uidic,microdisk laser,spectral modulation
更新于2025-09-12 10:27:22
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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) - Characteristics of Injection Microdisk Lasers with InGaAs/GaAs Quantum Well-Dots
摘要： Quantum dot (QD) based microdisk/microring lasers have attracted attention as promising candidates for on-chip optical interconnects since they offer small footprint, high-temperature stability and in-plane light emission. An important property required for a laser intended for optical communication is high-frequency direct modulation. Edge emitting QD-based lasers on GaAs demonstrated promising modulation characteristics with a -3 dB modulation bandwidth in excess of 7.4 GHz [1]. Meanwhile, there are practically no reports on the dynamic characteristics of QD-based microdisk/microring lasers. In the present work, we report on characteristics of microdisk lasers on GaAs substrates with diameters less than 30 μm. An ultra-dense (several 1011 cm-2) array of narrow-bandgap In-rich islands inside an In-depleted residual quantum well is used as the active region. These nanostructures are referred to as quantum well-dots (QWDs) [2] as their properties can be tuned from quantum well like to quantum dot like depending upon the composition and thickness of material deposited. Owing to a high density of the islands, a higher optical gain is achieved as compared to that of conventional In(Ga)As QDs, whereas the lateral carrier transport is suppressed as opposed to a quantum well. An epitaxial wafer was grown on an n+-GaAs(100)6o substrate by low pressure MOVPE using hydrogen as a carrier gas, arsine as a group V precursor, trimethylgallium, trimethylindium, and trimethylaluminum as group III precursors, silane and diethylzinc as n-type and p-type dopants. An Al0.34Ga0.66As/GaAs laser heterostructure comprises a 0.8 μm-thick GaAs separate confinement layer with 5 layers of QWDs formed by the deposition of 8 monolayers In0.4Ga0.6As and separated with 40 nm-thick GaAs spacers. Laser microresonators were formed by single-step photolithography and dry etching of 5.5 μm-high mesas with nearly vertical sidewalls. Ohmic contacts were formed with AgMn/NiAu and AuGe/Ni/Au metallizations upon the p+ GaAs cap layer and the n-doped GaAs substrate, respectively. The measurements were done at room temperature without external temperature stabilization and cooling. In a 30-μm diameter microdisk laser with InGaAs QWDs a high output power of 18 mW and a peak electrical-to-optical power conversion efficiency of 15 % were demonstrated. CW lasing was observed up to 110oC [3]. A maximum -3 dB modulation frequency of 5.9 GHz was found in the microdisk with a diameter less than 30 μm. To the best of our knowledge, these microlasers are the smallest QD microdisk/microring lasers, for which a direct modulation has been realized. Owing to a reduced cavity volume, a modulation current efficiency factor of 1.5 GHz/mA1/2 was estimated, and bias currents, at which the maximal modulation frequency is achieved is in the range of 30 mA (for comparison, MCEF of 0.38 GHz/mA1?2 and injected current of 86 mA was reported in [4]). The K-limited maximal frequency of 13 GHz was estimated from the modulation response analysis, whereas the experimentally measured –3 dB modulation frequency is 5.9 GHz. We suggest the bandwidth is limited by thermal effects or RC parasites, or a combination of those.
关键词： high-frequency direct modulation,microdisk lasers,optical interconnects,quantum well-dots,Quantum dot
更新于2025-09-12 10:27:22
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Lasing characteristics of a pyrromethene597-doped microdisk laser fabricated by the ink-jet printing method
摘要： A microdisk laser based on the fluorinated hyper branched polymer FC-V-50 was fabricated on an FEP (fluorinated ethylene propylene) substrate with the use of the ink-jet printing method. Pyrromethene597 doped 10 wt.% FC-V-50 solution in ethanol was used for the fabrication of a microdisk laser. The FC-V-50 polymer is characterized by a carboxyl functional group, which can be activated and attached to an amine group found in biomolecules. Based on the lasing characteristics, it is found that the microdisk laser has a relatively low lasing threshold of 34.51 μJ mm?2 and a reasonable Q factor of 7.52 × 103 at 586.59 nm. Therefore, the microdisk can be used for biosensing. The root mean square (RMS) of the surface roughness of the microdisk was estimated to be 6.2 nm. The surface roughness results scattering losses and limits the Q factor. This work reports the first demonstration of a microdisk laser based on FC-V-50 for biosensing applications.
关键词： ink-jet printing,microdisk laser,pyrromethene597,biosensing,FC-V-50
更新于2025-09-11 14:15:04
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[IEEE 2019 International Topical Meeting on Microwave Photonics (MWP) - Ottawa, ON, Canada (2019.10.7-2019.10.10)] 2019 International Topical Meeting on Microwave Photonics (MWP) - Silicon Photonic Microdisk Sensor Based on Microwave Photonic Filtering Technique
摘要： A high-sensitivity and high-resolution silicon photonic sensor based on a microwave photonic filtering technique is proposed and demonstrated. By employing a Mach-Zehnder modulator with a fixed 90° hybrid and a single DC bias control, this simple optical configuration is adopted to first tailor the amplitude of the optical field to achieve a power ratio in the sidebands which is then followed by an over-coupled integrated microdisk resonator (MDR) to provide a power equalization and π rad phase difference in the sidebands. The proposed scheme enables a highly effective cancellation of the beating signals at RF frequencies corresponding to the MDR notch center, resulting in an ultrahigh-rejection notch in the RF domain. A change in the environmental parameters can thus be detected with high sensing resolution by monitoring the frequency shifts of the ultranarrow RF notch. The use of the MDR contributes to a high sensing sensitivity while the fabrication requirements on having an ultrahigh Q factor is removed. A temperature sensor based on the proposed scheme is demonstrated as a proof-of-concept, presenting a temperature sensitivity of 9.91 GHz/°C and a 25 times improvement in the sensing resolution compared to the conventional optical sensing method based on direct measurement of the optical spectrum.
关键词： silicon photonics,Microwave photonics,microdisk,sensors
更新于2025-09-11 14:15:04
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[IEEE 2019 SBFoton International Optics and Photonics Conference (SBFoton IOPC) - Sao Paulo, Brazil (2019.10.7-2019.10.9)] 2019 SBFoton International Optics and Photonics Conference (SBFoton IOPC) - Fabrication of cylindrical resonant microcavities using the confinement provided by partially oxidized AlGaAs/GaAs layers
摘要： Two different interfaces for optical con?nement in GaAs resonators (air/GaAs/air, air/GaAs/AlOx) are compared in cylindrical microstructures with 10 μm of diameter. The AlOx is obtained by the lateral oxidation of Al0.9Ga0.1As layers. The spectrum of the resonators is obtained using a tapered ?ber system in the wavelength range between 1470 nm and 1610 nm. The modal separation agrees with simulations. The quality factor for the cylindrical microstructures having air/GaAs/air interface is almost twice the value for the case of AlOx interface. Since it is expected that surface recombination velocity is reduced by a factor of ten for this last case, these structures are expected to be suitable for the development of active resonators.
关键词： whispering gallery modes,quality factor,microdisk,oxidation of AlGaAs
更新于2025-09-11 14:15:04