Reduced graphene oxides with varying degrees of reduction have been produced by hydrazine reduction of graphene oxide. The linear and nonlinear optical properties of both graphene oxide as well as the reduced graphene oxides have been measured by single beam Z-scan measurement in the picosecond region. The results reveal both saturable absorption and two-photon absorption, strongly dependent on...

Riju C. Issac S. S. Harilal Geetha K. Varier C. V. Bindhu V. P. N. Nampoori C. P. G. Vallabhan Cochin University of Science and Technology International School of Photonics Laser Division Cochin 682 022, India Abstract. Pulsed photoacoustic studies in solutions of C70 in toluene are made using the 532-nm radiation from a frequency-doubled Nd:YAG laser. It is found that contrary to expectation, ...

We report our experimental results of nonlinear absorption and excited state dynamics in Rhodamine B solutions at 532 nm, on resonance of the absorption band and 600 nm at the absorption edge, studied using the standard Z-scan and degenerate four wave mixing techniques. We observed saturable absorption at 532 nm and a transition from saturable absorption to reverse saturable absorption at 600 n...

Saturable absorbers (SAs) have been regarded as a low-cost yet robust and compact solution to pulse generation in different fiber solid-state ultrafast lasers. Following the development of artificial SAs semiconductor SA mirrors, carbon nanotube (CNT) graphene are discovered employed for well In past decade, growing number based on new materials like MXenes metal halide perovskites emerged, whi...

A high-speed all-optical modulator is a key device in next-generation communication systems. Due to easy fabrication and an effective modulation effect, two-dimensional (2D) material–microfiber structure modulators have aroused much attention. Graphdiyne (GDY) excellent nonlinear optical material expected be utilized modulators. In this work, we demonstrate GDY-coated temporal according its sat...

The reverse saturable absorption and the optical-limiting response of metal phthalocyanines can be enhanced by use of the heavy-atom effect. Phthalocyanines containing heavy-metal atoms, such as In, Sn, and Pb, show a nearly factor-of-2 enhancement in the ratio of effective excited-state to ground-state absorption cross sections compared with those containing lighter atoms, such as Al and Si. I...

Carrier lifetime reduction resulting from proton bombardment of InGaAs/InP-based semiconductor saturable absorbers was studied experimentally, using a standard degenerate, cross-polarized pump-probe technique. Proton bombardment reduced carrier lifetimes by as much as a factor of 40 at low optical excitation densities. For high fluences, significant induced absorption was observed. The recovery...

We report experimental results on a highly efficient optical limiter that uses a three-mirror, multipass ring configuration. The optical limiter's enhanced performance is based on the accumulative effect that is achieved when the laser beam passes through the sample several consecutive times. Its feasibility was demonstrated for media with different limiting action processes, namely, reverse sa...