Abstract
The nonlinear optical absorption properties of Au-Ag nanoparticles (NPs) were studied using an open-aperture Z-scan under a nanosecond pulsed laser with wavelengths of 450 nm, 510 nm, 550 nm, and 600 nm. The experimental results demonstrated that, when the laser intensity was 1.04 × 1013 W/m2, the Au-Ag NPs showed saturated absorption (SA). When the laser intensity was increased to 3.03 × 1013 W/m2, the switch from SA to reverse saturation absorption (RSA) occurred. The nonlinear absorption and its transformation were analyzed by using local surface plasmon resonance (LSPR) effect, bleaching of ground state plasmon, and free carrier absorption theory.
Highlights
The surface plasmon resonance (SPR) effect can cause metal NPs to have enhanced nonlinearity [1], which may be suitable for many prospective applications such as biosensors [2,3], biomedical applications [4,5], optical switching, optical limiting, nanophotonics [6], three-dimensional imaging [7], and antibacterial agents [8]
The core-shell nanostructure is a new type of nanostructure with particular properties that are entirely different from the single-component nanostructure, which were widely used in many fields [29]
Most of the known investigations on the optical nonlinearity of Au-Ag NPs were conducted under a single laser wavelength
Summary
The surface plasmon resonance (SPR) effect can cause metal NPs to have enhanced nonlinearity [1], which may be suitable for many prospective applications such as biosensors [2,3], biomedical applications [4,5], optical switching, optical limiting, nanophotonics [6], three-dimensional imaging [7], and antibacterial agents [8]. Most of the known investigations on the optical nonlinearity of Au-Ag NPs were conducted under a single laser wavelength. It is of great significance to investigate the optical nonlinearity of NPs by using different laser wavelengths. Of all the nonlinear optical properties, saturated absorption (SA) and reverse sa2tuorfa7tion absorption (RSA) have important research values. This phenomenon indicates that the sample exhibited SA. Under the excitation energy of 760 μJ, when the sample cuvette moved gradually to the focus, the normalized transmittance increased first and decreased, which indicates that the sample exhibited SA at first, and switched to RSA.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
