OPTICAL NONLINEARITY OF CdSe AND CdSe-C60 QUANTUM DOT

2008 ◽  
Vol 22 (32) ◽  
pp. 3207-3213 ◽  
Author(s):  
HAO SONG ◽  
YUE-YING ZHAI ◽  
ZHANG-KAI ZHOU ◽  
ZHONG-HUA HAO ◽  
LI ZHOU
Keyword(s):  
Quantum Dots ◽  
Nonlinear Refraction ◽  
Refraction Index ◽  
Optical Nonlinearity ◽  
Cdse Quantum Dots ◽  
Cdse Qds ◽  
Third Order ◽  
Picosecond Pulses ◽  
Nonlinear Properties ◽  
The Third

The third-order optical nonlinear properties of CdSe quantum dots (QDs) and CdSe - C 60 QDs are investigated by Z-scan technique with picosecond pulses at the wavelength of 800 nm. The value of the nonlinear absorption coefficient β of CdSe - C 60 QDs is measured to be 2.9 cm/GW, which is about two times larger than that of CdSe QDs. The nonlinear refraction index γ of CdSe - C 60 QDs is -2.8 × 10-3 cm 2/ GW , which is about seven times larger than that of CdSe QDs. Presence of C 60 contributes to the larger optical nonlinearity of CdSe - C 60 QDs comparing with CdSe QDs.

scholarly journals Facile synthesis of ZnS–Ag2S core–shell nanospheres with enhanced nonlinear refraction

2019 ◽  
Vol 31 (2) ◽  
pp. 1283-1292 ◽  
Author(s):  
Azadeh Haghighatzadeh ◽  
Mitra Kiani ◽  
Babak Mazinani ◽  
Joydeep Dutta
Keyword(s):  
Electron Microscopy ◽  
Diffuse Reflectance Spectroscopy ◽  
Nonlinear Refraction ◽  
Optical Nonlinearity ◽  
Thin Layers ◽  
Refractive Indices ◽  
Nanosecond Laser ◽  
Core Shell ◽  
Third Order ◽  
The Third

AbstractZnS–Ag2S core–shell nano/hetero-junctions have been synthesized by a two-step co-precipitation technique, in which thin layers of Ag2S have been successfully coated on the surface of ZnS nanospheres. Structural studies and elemental analysis have been performed using X-ray diffraction, Fourier transfer infrared spectroscopy, field emission scanning electron microscopy, energy dispersive spectroscopy, and high-resolution transmission electron microscopy. UV–Vis diffuse reflectance spectroscopy and photoluminescence spectroscopy have been employed to investigate linear optical characteristics. Nanosecond laser pulsed-based single-beam Z-scan analysis has been used to examine the magnitude and the sign of the third-order nonlinear refractive indices. Samples show negative values of nonlinear refractive indices indicating self-defocusing optical nonlinearity under 1064 nm excitation. The results have shown that the third-order nonlinear refractive index in ZnS nanospheres can reach the magnitude of $$61.0 \times 10^{ - 12} {\text{m}}^{2} /{\text{W}}$$61.0×10-12m2/W by encapsulating such a nanostructure within nanometer shells of Ag2S. The enhanced nonlinearity for ZnS–Ag2S core–shells has been found to be 9 times higher than sole ZnS nanoparticles, which was estimated to be about $$6.4 \times 10^{ - 12} {\text{m}}^{2} /{\text{W}}$$6.4×10-12m2/W.

scholarly journals Size Dependent Optical Nonlinearity and Optical Limiting Properties of Water Soluble CdSe Quantum Dots

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Anju K. Augustine ◽  
S. Mathew ◽  
P. Radhakrishnan ◽  
V. P. N. Nampoori ◽  
M. Kailasnath
Keyword(s):  
Quantum Dots ◽  
Nonlinear Behavior ◽  
Optical Limiting ◽  
Optical Nonlinearity ◽  
Water Soluble ◽  
Saturable Absorption ◽  
Reverse Saturable Absorption ◽  
Cdse Quantum Dots ◽  
Cdse Qds ◽  
High Laser

We present third-order optical nonlinear absorption in CdSe quantum dots (QDs) with particle sizes in the range of 4.16–5.25 nm which has been evaluated by the Z-scan technique. At an excitation irradiance of 0.54 GW/cm2 the CdSe QDs exhibit reverse saturation indicating a clear nonlinear behavior. Nonlinearity increases with particle size in CdSe QDs within the range of our investigations which in turn depends on the optical band gap. The optical limiting threshold of the QDs varies from 0.35 GW/cm2 to 0.57 GW/cm2 which makes CdSe QDs a promising candidate for reverse-saturable absorption based devices at high laser intensities such as optical limiters.

scholarly journals Synthesis and Third-Order Nonlinear Synergistic Effect of ZrO2/RGO Composites

Nanomaterials ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 2741
Author(s):  
Xinting Zhao ◽  
Fangfang Wang ◽  
Jiawen Wu ◽  
Baohua Zhu ◽  
Yuzong Gu
Keyword(s):  
Graphene Oxide ◽  
Modulation Depth ◽  
Graphene Nanosheets ◽  
Nonlinear Refraction ◽  
Nonlinear Susceptibility ◽  
Zro2 Nanoparticles ◽  
Third Order ◽  
Nonlinear Properties ◽  
The Third ◽  
Nonlinear Modulation

Tuning the third-order nonlinear properties of graphene by hybrid method is of great significance in nonlinear optics research. ZrO2/reduced graphene oxide (RGO) composites with different ZrO2 concentrations were prepared by a simple hydrothermal method. The morphology and structure show that ZrO2 nanoparticles were uniformly dispersed on the surface of graphene nanosheets. The nonlinear optical (NLO) characteristics of composites with different ZrO2 concentrations were studied by the Z-scan technique of 532 nm picosecond pulsed laser. The results showed that ZrO2/RGO composites had saturated absorption and positive nonlinear refraction characteristics. Meanwhile, the third-order nonlinear susceptibility of the ZrO2/RGO composite with a 4:1 mass ratio of ZrO2 to graphene oxide could reach 23.23 × 10−12 esu, which increased tenfold compared to RGO, and the nonlinear modulation depth reached 11.22%. Therefore, the NLO characteristics could be effectively adjusted by controlling the concentration of ZrO2, which lays a foundation for further research on the application of ZrO2/RGO composites in NLO devices.

scholarly journals Tunable Nonlinear Optical Property of MnS Nanoparticles with Different Size and Crystal Form

Nanomaterials ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 34
Author(s):  
Zhihao Zhang ◽  
Pengchao Li ◽  
Yuzong Gu
Keyword(s):  
Optical Property ◽  
Nonlinear Optical ◽  
Nonlinear Optical Property ◽  
Nonlinear Refraction ◽  
Synthesis Method ◽  
Crystal Form ◽  
Optical Nonlinearity ◽  
Photon Absorption ◽  
Third Order ◽  
Crystal Forms

It is significant to study the reason that semiconductor material has adjustable third-order optical nonlinearity through crystal form and dimensions are changed. αMnS nanoparticles with different crystal forms and sizes were successfully prepared by one-step hydrothermal synthesis method and their size-limited third-order nonlinear optical property was tested by Z-scan technique with 30 ps laser pulses at 532 nm wavelength. Nanoparticles of different crystal forms exhibited different NLO (nonlinear optical) responses. γMnS had stronger NLO response than αMnS because of higher fluorescence quantum yield. Two-photon absorption and the nonlinear refraction are enhanced as size of nanoparticlesreduced. The nanoparticles had maximum NLO susceptibility which was 3.09 × 10−12 esu. Susceptibility of αMnS increased about nine times than that of largest nanoparticles. However, it was reduced when size was further decreased. This trend was explained by the effects of light induced dipole moments. And defects in αMnS nanoparticles also had effect on this nonlinear process. MnS nanoparticles had potential application value in optical limiting and optical modulation.

Contribution of the 2 ^1Ag state to the third-order optical nonlinearity in a squaraine dye: errata

1994 ◽  
Vol 19 (22) ◽  
pp. 1909 ◽  
Author(s):  
James H. Andrews ◽  
John D. V. Khaydarov ◽  
Kenneth D. Singer
Keyword(s):  
Optical Nonlinearity ◽  
Third Order ◽  
The Third ◽  
Squaraine Dye

scholarly journals Intense Visible Luminescence in CdSe Quantum Dots by Efficiency Surface Passivation with H2O Molecules

2012 ◽  
Vol 2012 ◽  
pp. 1-6
Author(s):  
Hyeoung Woo Park ◽  
Do-Hyung Kim
Keyword(s):  
Heat Treatment ◽  
Quantum Dots ◽  
Quantum Yield ◽  
Surface Passivation ◽  
Cdse Quantum Dots ◽  
Cdse Qds ◽  
Effect Of Water ◽  
Visible Luminescence ◽  
Luminescence Efficiency

We have investigated the effect of water (H2O) cooling and heat treatment on the luminescence efficiency of core CdSe quantum dots (QDs). The photoluminescence (PL) quantum yield of the CdSe QDs was enhanced up to ~85%, and some periodic bright points were observed in wide color ranges during the heat treatment of QDs mixed with H2O. The PL enhancement of QDs could be attributed to the recovery of QDs surface traps by unreacted ligands confined within the hydrophilic H2O molecule containers.

Developed one-pot synthesis of dual-color CdSe quantum dots for white light-emitting diode application

2018 ◽  
Vol 6 (12) ◽  
pp. 3089-3096 ◽  
Author(s):  
Sheng Dai ◽  
Cyuan-Bin Siao ◽  
Shu-Ru Chung ◽  
Kuan-Wen Wang ◽  
Xiaoqing Pan
Keyword(s):  
Quantum Dots ◽  
White Light ◽  
Light Emitting Diode ◽  
Cdse Quantum Dots ◽  
Cdse Qds ◽  
One Pot ◽  
Synthetic Process ◽  
Light Emitting ◽  
One Pot Synthesis ◽  
Enhanced Stability

The size and fraction of red and green CdSe QDs can be controlled precisely during the synthetic process, thus manifesting remarkably enhanced stability.

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