Effect of Au coating on optical properties of CdS nanoparticles and their optical limiting studies

Facile one-step fabrication of upconversion fluorescence carbon quantum dots anchored on graphene with enhanced nonlinear optical responses

“…For QDs, the generally accepted underlying OL mechanisms are two-photon and/or multiphoton absorption for pico-to femtosecond laser pulses and free-carrier absorption and/or NLS for nanosecond laser pulses. [19][20][21][35][36][37][38] By the closed-aperture Z-scan techniques, which can conveniently and effectively distinguish between NLA and NLR, it was conrmed that NLR made no contribution to the observed NLO and OL behavior of the CQD/GO hybrid in response to nanosecond laser irradiation in our experiments. To separate the contributions of NLA and NLS, we used a Z-scan setup following Joudrier and Rao 45,46 and the results are shown in Fig.…”

“…3 Extensive research has been performed on optical limiters in the past 20 years, and the strong OL properties of a wide range of materials have been intensively studied, from organic dyes (phthalocyanine, porphyrin, fullerene), [4][5][6][7][8][9] carbon nanomaterials (carbon black, carbon nanotubes, graphene) [10][11][12][13][14][15] to noble metal nanoparticles (NPs) [16][17][18] and quantum dots. [19][20][21] Typically, the occurrence of OL effects in materials arises from three main classes of mechanisms: nonlinear absorption (NLA), nonlinear scattering (NLS), and nonlinear refraction (NLR).…”

Influence of yttrium doping on the nonlinear optical limiting properties of cadmium molybdate nanostructures

“…[44][45][46] Similar work on the optical limiting properties and PA of Au coated CdS nanoparticles was reported by Mathew et al and it was concluded that coupling of the local eld effect by surface plasmon resonance (SPR) and excitonic oscillator strength of the CdS nanoparticles contributes to an enhancement in the optical nonlinearity. 47 In our case, the enhancement in nonlinearity is due to the generation of impurity energy levels and creation of oxygen defects caused by substitution of Y 3+ ions into the CdMoO 4 matrix. The formation of oxygen vacancies can introduce dopant energy levels, which extract the photogenerated electrons from the conduction band, thereby increasing the photo-absorption and separation rate of charge carriers.…”

Interferometry Method as a Way to Find Nonlinear Optical Responses of Nanoparticles

“…In last few decades, the optical properties of nanoparticles have received considerable attention around the world [1][2][3]. There are different methods for evaluation of optical properties of nanoparticles.…”