Wavelength-Dependent Nonlinear Absorption in Palladium Nanoparticles

Chunyu Chen,Yachen Gao,Jun Wang

doi:10.3390/app11041640

Chunyu Chen, Yachen Gao + Show 1 more

Open Access

https://doi.org/10.3390/app11041640

Copy DOI

Abstract

This paper aims to study the nonlinear absorption characteristics of palladium nanoparticles (PdNPs) at off-resonant wavelengths. For this purpose, multi-wavelength (500–650 nm) nanosecond Z-scan technique was used. The experimental results indicate that saturated absorption (SA) and the transition from SA to reverse saturated absorption (RSA) can occur, and depends on the excitation wavelength and energy. When the excitation wavelength is constant, with the increase of excitation energy, PdNPs change from SA to RSA. When the excitation energy is constant, with the excitation wavelength approaching surface plasmon resonance (SPR), PdNPs change from SA to RSA. This phenomenon of SA and RSA under multi-wavelength excitation in the off-resonant region provides a supplement for the systematic study of the nonlinear absorption of PdNPs.

Highlights

When the light is not strong, the optical response of a material usually scales linearly with the amplitude of the optical electric field
Nonlinear absorption is of importance since the nonlinearities considerably change the propagation of intense light through the medium, which can induce novel applications in optoelectronics, optical switchers and limiters
The absorption with the absorption coefficient increasing with the increase of incident light intensity is called reverse saturated absorption (RSA)

Summary

Introduction

When the light is not strong, the optical response of a material usually scales linearly with the amplitude of the optical electric field. At high optical powers, the optical properties of material are no longer linearly related to the intensity of the incident light. Nonlinear absorption is of importance since the nonlinearities considerably change the propagation of intense light through the medium, which can induce novel applications in optoelectronics, optical switchers and limiters. Nonlinear absorption includes saturated absorption (SA) and reverse saturated absorption (RSA). The absorption with the absorption coefficient decreasing with the increase of incident light intensity is called SA.

Objectives

Methods

Conclusion