Ultrafast and short pulse optical nonlinearity in isolated, sparingly sulfonated water soluble graphene

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• 作者：Sreekanth Perumbilavil^a ; ¹ ; Kishore Sridharan^b ; ^{kishore@nitk.edu.in" class="auth_mail" title="E-mail the corresponding author} ; ^{sridharankishore@gmail.com" class="auth_mail" title="E-mail the corresponding author} ; Dibyashree Koushik^a ; Pranitha Sankar^a ; ^b ; V.P. Mahadevan Pillai^c ; Reji Philip^a ; ^{reji@rri.res.in" class="auth_mail" title="E-mail the corresponding author}
• 刊名：Carbon
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：111
• 期：Complete
• 页码：283-290
• 全文大小：2592 K

文摘

We report the nonlinear optical properties of graphene oxide (GO), reduced graphene oxide (rGO), sulfonated graphene oxide (S-rGO), and sparingly sulfonated water soluble graphene (WSG), measured under ultrafast (100 fs) and short pulse (300 ps, 50 ns) laser excitations at 800 nm, employing the open aperture Z-scan technique. The samples exhibit typical third order nonlinear optical behaviour including two-photon absorption (2 PA), reverse saturable absorption (RSA), and saturable absorption (SA). A significant variation in the nature of nonlinear absorption is seen when the laser pulse duration is changed. For example, RSA is prominent under nanosecond (ns) excitation, 2 PA is prevalent under femtosecond (fs) excitation, and SA is dominant under picosecond (ps) excitation. For comparison purposes the measurements are repeated using 5 ns laser pulses at 532 nm. RSA is enhanced in WSG in the nanosecond excitation domain, which can be attributed to the covalent bonding between p-phenyl-SO₃H groups and sp² graphitic planes. WSG exhibits a switching behaviour from SA to RSA upon increasing the excitation intensity under fs excitation. Results show that these graphene derivatives are potentially useful for saturable absorber and optical limiter device applications.