@Article{CL.2023.205.353,
AUTHOR = {P. Yadav, C. Tyagi, A. Devi, N. Gahlot},
TITLE = {Study of femtosecond nonlinear optical coefficients for Bi doped Se<sub>85-x</sub>Te<sub>15</sub>Bi<sub>x</sub> chalcogenide thin films},
JOURNAL = {Chalcogenide Letters},
VOLUME = {20},
YEAR = {2023},
NUMBER = {5},
PAGES = {353--365},
URL = {http://www.techscience.com/CL/v20n5/65287},
ISSN = {1584-8663},
ABSTRACT = {The present work reports the influence of selenium replacement by bismuth on the 
nonlinear optical parameters of ternary Se<sub>85-x</sub>Te<sub>15</sub>Bi<sub>x</sub> (x=0, 1, 2, 3, 4, 5 atomic %) 
chalcogenide thin films. Calculation of nonlinear refractive index (n<sub>2>/sub>), two-photon 
absorption coefficient (β<sub>2>/sub>) and third-order susceptibility (χ
<sup>(3)</sup>
) by well known Z-scan 
technique with femtosecond laser pulses were done. The Z-scan spectra for Se<sub>85-x</sub>Te<sub>15</sub>Bi<sub>x</sub> 
upto Bi= 4 atomic % results in self- focusing behavior of n<sub>2>/sub> is positive while for Bi=5 
atomic % n<sub>2>/sub> is negative. The behavior of n<sub>2>/sub> by using different physical parameters are 
exlpained. The comparison of experimental and theoretical values of n<sub>2>/sub> with pure silica are 
also studied. The presence of the valley at focus in open aperture Z-scan graph 
demonstrates strong reverse saturable absorption. The figure of merit (FOM) for the SeTe-Bi
chalcogenide thin films is found to be less than 1 and are beneficial for all-optical 
switch devices. },
DOI = {10.15251/CL.2023.205.353}
}