scholarly journals Генерация высших гармоник при распространении предельно короткого оптического импульса в среде углеродных нанотрубок с нелинейным поглощением

2020 ◽  
Vol 128 (4) ◽  
pp. 535
Author(s):  
Н.Н. Конобеева ◽  
М.Б. Белоненко
Keyword(s):  
Carbon Nanotubes ◽  
Absorption Coefficient ◽  
Nonlinear Absorption ◽  
Optical Pulse ◽  
Pulse Field ◽  
Published Data ◽  
Linear Absorption Coefficient ◽  
Linear Absorption ◽  
Calculated Dependence ◽  
Short Optical Pulse

The problem of the propagation of an extremely short optical pulse in a medium of carbon nanotubes with nonlinear absorption and amplification is considered. Nonlinear absorption is described phenomenologically based on published data. The mode in which the gain is higher than the linear absorption coefficient is considered. This mode is also described phenomenologically. The extremely short optical pulse is considered on the basis of Maxwell's equations, with a microscopically calculated dependence of the current on the pulse field. The possibility of efficient generation of higher harmonics that are not initially present in the pulse is shown.

scholarly journals Methotrexate Detection Based On The Optical Properties Of Carbon Nanotubes And Silver Nano Particles Nanocomposites

2021 ◽  
Vol 7 (3) ◽  
pp. 1323
Author(s):  
Fida Mohammad Mohammadi
Keyword(s):  
Carbon Nanotubes ◽  
Refractive Index ◽  
Nonlinear Refractive Index ◽  
Nano Particles ◽  
Optical Measurements ◽  
Carbon Electrode ◽  
Linear Absorption Coefficient ◽  
Linear Absorption ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

<p>In this experiment, glassy carbon electrode with multi walled carbon nanotubes<br />nanocomposites have been prepared in different concentration in order to see if<br />methotrexate is anticancer drug. For the purpose of characterizing the structures,<br />nanocomposites were analyzed by scanning electron microscope. Optical measurements of different concentrations were conducted by z-scan method and the results show that by rising the concentration, nonlinear refractive index and linear absorption coefficient increases. The values of nonlinear refractive index are in orders of 𝟏𝟎−𝟖 𝒄𝒎𝟐 𝒘.</p>

Peculiarities of extremely short optical pulses propagation in carbon nanotube medium with nonlinear absorption

2020 ◽  
Vol 34 (31) ◽  
pp. 2050358
Author(s):  
Natalia N. Konobeeva ◽  
Eduard G. Fedorov ◽  
Mikhail B. Belonenko
Keyword(s):  
Carbon Nanotubes ◽  
Nonlinear Absorption ◽  
Piezoelectric Effect ◽  
Pulse Field ◽  
Heavy Nuclei ◽  
Optical Pulses ◽  
Effective Equation ◽  
Electromagnetic Pulses ◽  
The Stability ◽  
Extremely Short Optical Pulses

In this paper, we study the propagation of extremely short electromagnetic pulses in a medium with zig–zag carbon nanotubes taking into account pumping and nonlinear absorption introduced phenomenologically. Based on Maxwell’s equations, we obtain an effective equation for the vector potential of the electromagnetic field, which takes into account the dissipation of the pulse field under the conditions of the piezoelectric effect associated with the vibrations of heavy nuclei of the medium, pumping by an external electromagnetic wave, and nonlinear absorption of carbon nanotubes. We demonstrate the stability of the electromagnetic pulse shape on a time scale that is significantly longer than the pulse duration but not exceeding the relaxation time.

Optical Absorption In Hg1−xCdxTe

1997 ◽  
Vol 484 ◽  
Author(s):  
Vaidya Nathan
Keyword(s):  
Experimental Data ◽  
Optical Absorption ◽  
Band Structure ◽  
Absorption Coefficient ◽  
Numerical Results ◽  
Recent Experimental Data ◽  
Narrow Gap ◽  
Interband Transitions ◽  
Linear Absorption Coefficient ◽  
Linear Absorption

AbstractThe theory of optical absorption due to interband transitions in direct-gap semiconductors is revisited. A new analytical expression for linear absorption coefficient in narrow-gap semiconductors is obtained by including the nonparabolic band structure due to Keldysh and Burstein-Moss shift. Numerical results are obtained for Hg1−xCdxTe for several values of x and temperature, and compared with recent experimental data. The agreement is found to be good.

scholarly journals Determination of the quasi-TE mode (in-plane) graphene linear absorption coefficient via integration with silicon-on-insulator racetrack cavity resonators

2014 ◽  
Vol 22 (15) ◽  
pp. 18625 ◽  
Author(s):  
Iain F Crowe ◽  
Nicholas Clark ◽  
Siham Hussein ◽  
Brian Towlson ◽  
Eric Whittaker ◽  
...  
Keyword(s):  
Absorption Coefficient ◽  
Silicon On Insulator ◽  
Linear Absorption Coefficient ◽  
Linear Absorption ◽  
Cavity Resonators ◽  
Te Mode

scholarly journals Effect of egg white, perlite, gypsum and fly ash in environment friendly insulation materials

2018 ◽  
Vol 16 (3) ◽  
pp. 329-342
Author(s):  
Hanifi Binici ◽  
Orhan Aksogan ◽  
Rifat Resatoglu
Keyword(s):  
Thermal Conductivity ◽  
Fly Ash ◽  
Absorption Coefficient ◽  
Egg White ◽  
Radiation Hazard ◽  
Binding Property ◽  
Insulation Material ◽  
Linear Absorption Coefficient ◽  
Linear Absorption ◽  
Insulation Materials

In this study, engineering features of insulation materials produced from egg white, perlite, gypsum and fly ash were investigated. Densities, water absorption ratios, ultrasonic velocities and thermal conductivity coefficients of samples were determined. Furthermore, linear absorption coefficient were measured by gamma ray saturation levels at 17.7, 26 and 60 keV energies. Thermal conductivity coefficients of the produced composites were found to be in the range 0.0882- 0.0995 Kcal/mh?C. Egg white decreased the linear absorption coefficients. Unit weights of samples were found to be dependent on their contents. As gypsum rate increased, unit weight also increased. As perlite rate increased thermal conductivity coefficient decreased. As egg white decreased the linear absorption coefficient decreased, also. The most important benefits of these types of materials are their being impermeable and perfectly compatible with the environment. These lighter type materials were/are compatible with Turkey and the Middle East environment. Egg white has been resistant to radiation. Hence, it is highly compatible with the environment. The compressive and flexural strengths of mortars decreased with the use of egg whites in mortar. So, egg white enhances the binding property of samples. In most cases, some organic and/or inorganic additives are used as well, to improve the physical and mechanical properties of mortar, such as egg whites and others. Finally, this study shows that it is possible to produce an insulation material resistant to sound and radiation by using egg white, perlite and fly ash. It is seen that the samples incorporating egg white could be used at hospitals, military and industrial facilities and shelters which are under radiation hazard. Furthermore, this insulation materials will be put to use in industry in Turkey after many experiments have been done on laboratory.

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