THE EFFECTS OF TEMPERATURE ON DIFFERENT LASER TRANSITIONS OF NEODYMIUM ORTHOVANADATE CRYSTAL

2016 ◽  
Vol 78 (3) ◽  
Author(s):  
Ganesan Krishnan ◽  
Noriah Bidin
Keyword(s):  
Laser Diode ◽  
Ground State ◽  
Phonon Scattering ◽  
Laser Crystal ◽  
Laser System ◽  
Temperature Dependent ◽  
Laser Transition ◽  
Level Laser ◽  
Effects Of Temperature ◽  
Terminal Level

The temperature dependence of Nd:YVO4 laser crystal pumped by laser diode emitting at 808 nm is studied within the range of 5 oC to 60 oC. The spectroscopy properties of quasi three level at 914 nm (4F3/2 - 4I 9/2) and four level at 1064 nm (4F3/2 - 4I 11/2) are characterized. The lineshape function of the transition lines were broadened as the temperature increases. The phenomenon is attributed to change in linewidth, lineshift and intensity. The linewidths for both laser transition of 914 nm and 1064 nm increases with temperature with the rate of 0.105 cm-1/oC and 0.074 cm-1/oC respectively. The peak of 914nm and 1064 nm lineshapes shifted to a longer wavelength with the rate of 3.0 pm/oC and 4.2 pm/oC respectively which correspond to same amount of lineshift. The lineshape broadening with respect to the temperature is due to one-phonon emission and Raman phonon scattering processes.  The intensities of 914 nm and 1064 nm transition lines are found to be decreased at the rate of 0.15 %/oC and 0.45 %/oC respectively due to non-radiative effects. Quasi three level laser transition is more temperature dependent because it terminal level is close to the ground state which suffers from higher phonon-ion interaction rather than four level laser system.

scholarly journals Увеличение эффективности тандема полупроводниковый лазер-оптический усилитель на основе самоорганизующихся 8s квантовых точек

2021 ◽  
Vol 55 (12) ◽  
pp. 1223
Author(s):  
А.Е. Жуков ◽  
Н.В. Крыжановская ◽  
Э.И. Моисеев ◽  
А.С. Драгунова ◽  
А.М. Надточий ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Excited State ◽  
Laser Diode ◽  
Ground State ◽  
Semiconductor Optical Amplifier ◽  
Optical Transition ◽  
Optical Amplifier ◽  
Rate Equations ◽  
Resonator Length ◽  
Optimal Value

The rate equations are used to analyze the characteristics of a tandem consisting of a laser diode and a semiconductor optical amplifier made of a single heterostructure with quantum dots. The optimal value of the current distribution coefficient the amplifier and the laser, as well as the optimal resonator length that provides the highest output power of the tandem were determined. It is shown that the use of the tandem allows, at the same total consumed current, to significantly (more than 4 times for 1 A) increase the power emitted through the ground-state optical transition in comparison with that achievable with a laser diode solely being limited by the onset of lasing through an excited-state optical transition.

scholarly journals Global dynamics of a Huanglongbing model with a periodic latent period

2021 ◽  
Vol 0 (0) ◽  
pp. 0
Author(s):  
Yan Hong ◽  
Xiuxiang Liu ◽  
Xiao Yu
Keyword(s):  
Reproduction Number ◽  
Threshold Value ◽  
Transmission Model ◽  
Threshold Dynamics ◽  
Global Dynamics ◽  
Temperature Dependent ◽  
Candidatus Liberibacter ◽  
Effects Of Temperature ◽  
Disease Free ◽  
The Basic Reproduction Number

<p style='text-indent:20px;'>Huanglongbing (HLB) is a disease of citrus that caused by phloem-restricted bacteria of the Candidatus Liberibacter group. In this paper, we present a HLB transmission model to investigate the effects of temperature-dependent latent periods and seasonality on the spread of HLB. We first establish disease free dynamics in terms of a threshold value <inline-formula><tex-math id="M1">\begin{document}$ R^p_0 $\end{document}</tex-math></inline-formula>, and then introduce the basic reproduction number <inline-formula><tex-math id="M2">\begin{document}$ \mathcal{R}_0 $\end{document}</tex-math></inline-formula> and show the threshold dynamics of HLB with respect to <inline-formula><tex-math id="M3">\begin{document}$ R^p $\end{document}</tex-math></inline-formula> and <inline-formula><tex-math id="M4">\begin{document}$ \mathcal{R}_0 $\end{document}</tex-math></inline-formula>. Numerical simulations are further provided to illustrate our analytic results.</p>

Effects of Temperature and Charge Depletion on the Spin Density in Hydrogenated Amorphous Silicon

1991 ◽  
Vol 219 ◽  
Author(s):  
J.-K. Lee ◽  
E. A. Schiff
Keyword(s):  
Spin Density ◽  
Negative Charge ◽  
Temperature Dependent ◽  
Defect Model ◽  
Depletion Width ◽  
Initial Charge ◽  
Effects Of Temperature ◽  
Hydrogenated Amorphous ◽  
Spin Densities ◽  
Charge Depletion

ABSTRACTThe dependence of the spin density upon temperature and charge depletion is calculated based on the standard defect model in a-Si:H of a D-center with positive, neutral, and negative charge states. The results are compared with recent measurements of depletion width modulated spin densities and temperature-dependent spin densities. It is shown that the initial charge density assumed for the defect system substantially affects conclusions regarding electronic correlation energies drawn from the measurements.

scholarly journals Emission Characteristics of Fluorescent Labels with Respect to Temperature Changes and Subsequent Effects on DNA Microchip Studies

2005 ◽  
Vol 71 (10) ◽  
pp. 6453-6457 ◽  
Author(s):  
Wen-Tso Liu ◽  
Jer-Horng Wu ◽  
Emily Sze-Ying Li ◽  
Ezrein Shah Selamat
Keyword(s):  
Melting Curve ◽  
Melting Curve Analysis ◽  
Emission Characteristics ◽  
Fluorescent Labels ◽  
Temperature Dependent ◽  
Temperature Changes ◽  
Formamide Concentration ◽  
Effects Of Temperature ◽  
Microarray Studies ◽  
Texas Red

ABSTRACT The effects of temperature, salt concentration, and formamide concentration on the emission characteristics of commonly used fluorescent labels were evaluated on DNA microchips. The emission intensities of different fluorophores without hybridization were observed to vary, each to a different extent, to mainly temperature changes. Rhodamine red, TAMRA (tetramethylrhodamine), and dyes from the carbocyanide group exhibited the largest variations, and Texas Red and Oregon Green exhibited the smallest variations. This temperature dependency was shown to affect results obtained during melting curve analysis in DNA microarray studies. To minimize the bias associated with the temperature-dependent emission of different fluorescent labels, a normalization step was proposed.

Evaluation of Luminescence Decay Measurements Probed on Pure and Doped Pt(IV) Hexahalogeno Complexes. II. Molecular Properties Obtained from Temperature Dependent Lifetime Curves

1997 ◽  
Vol 52 (5) ◽  
pp. 447-456
Author(s):  
Ingo Biertümpel ◽  
Hans-Herbert Schmidtke
Keyword(s):  
Excited States ◽  
Ground State ◽  
Energy Levels ◽  
Decay Rates ◽  
Rate Equations ◽  
Temperature Dependent ◽  
Lifetime Measurements ◽  
Thermally Activated ◽  
Ground State Energies ◽  
Higher Excited States

Abstract Lifetime measurements down to nearly liquid helium temperatures are used for determining energy levels and transition rates between excited levels and relaxations into the ground state. Energies are obtained from temperature dependent lifetimes by fitting experimental curves to model functions pertinent for thermally activated processes. Rates are calculated from solutions of rate equations. Similar parameters for pure and doped Pt(IV) hexahalogeno complexes indicate that excited levels largely belong to molecular units. Some of the rates between excited states are only somewhat larger than decay rates into the ground state, which is a consequence of the polyexponential decay measured also at low temperature (2 K). In the series of halogen complexes, the rates between spinorbit levels resulting from 3T1g increase from fluorine to bromine, although energy splittings become larger. Due to the decreasing population of higher excited states in this series, K^PtFö shows a tri-exponential, K2PtCl6 a bi-exponential and FoPtBr6 a mono-exponential decay. In the latter case the population density of higher excited states relaxes so fast that emission occurs primarily from the lowest excited Γ3(3T1g) level. Phase transitions and emission from chromophores on different sites can also be observed.

The phonon scattering mechanism and its effect on temperature dependent thermal and thermoelectric properties of the silver nanowire

2022 ◽  
Author(s):  
Gui-Cang He ◽  
Lina Shi ◽  
Yilei Hua ◽  
Xiao-Li Zhu
Keyword(s):  
Thermoelectric Properties ◽  
Phonon Scattering ◽  
Silver Nanowire ◽  
Scattering Mechanism ◽  
Temperature Dependent ◽  
Scattering Mechanisms ◽  
Phonon Structure

In this work, the electron-phonon, the phonon-phonon, and phonon structure scattering mechanisms and the effect on the thermal and thermoelectric properties of the silver nanowire (AgNW) are investigated in temperature...

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