Non-linear absorption coefficient measurement of thin films by Z-scan in near- and mid-infrared range

Author(s):  
Stuart J. Flanders ◽  
James W. M. Chon
Author(s):  
ARTHUR W. SNOW ◽  
JAMES S. SHIRK ◽  
RICHARD G. S. PONG

A series of methyl-terminated oligooxyethylene ( CH 3( OCH 2 CH 2)n O , n = 8.8)-substituted phthalocyanines with peripheral substitution at four β positions, at four α positions and at the eight α positions was synthesized and structurally characterized. These compounds are isotropic liquids above 10 °C. Non-linear optical properties of the tetra-α- and tetra-β-substituted compounds were examined. Both are reverse saturable absorbers in the visible region of the spectrum, but the tetra-α-substituted compound has the larger non-linear absorption coefficient and can be a useful optical limiter in cases where a non-volatile liquid is desirable.


1997 ◽  
Vol 484 ◽  
Author(s):  
Vaidya Nathan

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.


2014 ◽  
Vol 22 (15) ◽  
pp. 18625 ◽  
Author(s):  
Iain F Crowe ◽  
Nicholas Clark ◽  
Siham Hussein ◽  
Brian Towlson ◽  
Eric Whittaker ◽  
...  

2018 ◽  
Vol 16 (3) ◽  
pp. 329-342
Author(s):  
Hanifi Binici ◽  
Orhan Aksogan ◽  
Rifat Resatoglu

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.


2019 ◽  
Vol 974 ◽  
pp. 429-434
Author(s):  
D.V. Cherkasov ◽  
V.V. Avdonin ◽  
Y.V. Yurkin

Results of scientific researches in the field of creation of self-adhesive radiation shielding materials on the basis of polymers are presented in this article. It is stated, that radiation shielding coverings on the basis of ethylene propylene rubber are more preferable than coverings on the basis of BSR and SBS. Materials on the basis of ethylene propylene rubber possess high hardness at scaling from metal (more than 600 N/m) and hardness at breakoff from concrete (more than 0,1 MPa), have a high linear absorption coefficient.


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