Evaluation of emission cross section of CdSe quantum dots for laser applications

Yan, Jun; Wang, C G; Zhang, H; Cheng, Chien‐Hong

doi:10.7452/lapl.201210037

Cited by 11 publications

(2 citation statements)

References 17 publications

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“…ZnS-capped CdSe QDs properties have generated a great deal of interest due to the scientific aspects that are involved in these studies. Examples of interesting and significant physics include: fluorescent biological imaging probes (Mukherjee & Ghost, 2012), solar cell devices (Kashyout et al, 2012), white light emitting diodes (Nizamoglu & Demir, 2009), nano lasers (Yan et al, 2012), and optical fiber sensors (Jorge et al, 2009). In all these technological applications, the unique optical properties of QDs are size dependent.…”

Section: Introductionmentioning

confidence: 99%

CdSe-ZnS Core-Shell Quantum Dots: Surface Plasmons Effect and Optical Spectra

Mohammed¹

2013

APR

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Absorption and photoluminescence (PL) spectra of a colloidal CdSe-ZnS core-shell quantum dots (QDs) were measured within the strong confinement regime. The QDs were casted on half-coated quartz substrates with 50 nm of gold and prepared for studying the surface plasmons effect. The samples were optically arranged and pumped by different wavelengths, and the PL spectra were detected. Excitation with a wavelength of 400 nm reveals a structure fluorescence spectrum which consists of five distinct bands. These bands are more intense and resolved than the corresponding traditional weak absorption bands. They were detected for the first time and assigned according to the theoretical predictions of excitons in a spherical potential with Coulomb interactions and valence bands mixing. A scheme based on multiple exciton generation (MEG) for the appearance of the fluorescence bands was proposed. This scheme was confirmed by the recent theoretical prediction using the state-of-the art time domain ab initio density functional theory and the atomistic pseudopotential calculations. The detected surface plasmons effect in QDs enhances the intensity of the fluorescence bands. This surface plasmons effect facilitated the appearance of these mentioned bands in more intensive features than the corresponding traditional weak absorption bands. Furthermore, the reduction in the measured lifetime of the first excited electronic state from 20 ns for the QDs deposited directly on the quartz substrate to 7 ns for the QDs casted on the gold film, gives a further evidence of the surface plasmons effect in the (PL) of the CdSe-ZnS QDs.

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Section: Introductionmentioning

confidence: 99%

CdSe-ZnS Core-Shell Quantum Dots: Surface Plasmons Effect and Optical Spectra

Mohammed¹

2013

APR

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“…In these conditions, absorption and emission cross sections can be deduced by fitting to Equation (4) the experimental results presented in Figure 4d (from data in Figure 4c) for the 140 mm long PNC-doped HC-NCF (blue hollow squares). For this purpose, σa and σe can be related with McAmber theory [45] by σe=σaexp((E−hνs)/kBnormalT), where the energy kBT = 25.7 meV, the energy E corresponds to the energy associated with the absorption edge (i.e zero phonon energy) and hνs is the signal transition energy. Thus, the McAmber theory yields coefficient of σe/σa = 5.6.…”

Section: Resultsmentioning

confidence: 99%

Optical Amplification in Hollow-Core Negative-Curvature Fibers Doped with Perovskite CsPbBr3 Nanocrystals

et al. 2019

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We report a hollow-core negative-curvature fiber (HC-NCF) optical signal amplifier fabricated by the filling of the air microchannels of the fiber with all-inorganic CsPbBr3 perovskite nanocrystals (PNCs). The optimum fabrication conditions were found to enhance the optical gain, up to +3 dB in the best device. Experimental results were approximately reproduced by a gain assisted mechanism based on the nonlinear optical properties of the PNCs, indicating that signal regeneration can be achieved under low pump powers, much below the threshold of stimulated emission. The results can pave the road for new functionalities of the HC-NCF with PNCs, such as optical amplification, nonlinear frequency conversion and gas sensors.

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