scholarly journals Wavelength-Dependent Optical Nonlinear Absorption of Au-Ag Nanoparticles

2021 ◽  
Vol 11 (7) ◽  
pp. 3072
Author(s):  
Jun Wang ◽  
Yabin Shao ◽  
Chunyu Chen ◽  
Wenzhi Wu ◽  
Degui Kong ◽  
...  
Keyword(s):  
Ag Nanoparticles ◽  
Nonlinear Absorption ◽  
Laser Intensity ◽  
Free Carrier Absorption ◽  
Ag Nps ◽  
Local Surface Plasmon Resonance ◽  
Reverse Saturation Absorption ◽  
Nonlinear Optical Absorption ◽  
Nanosecond Pulsed Laser ◽  
Carrier Absorption

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.

Nonlinear Absorption Properties of Spherical Gold Colloidal Nanoparticles

2012 ◽  
Vol 476-478 ◽  
pp. 923-927 ◽  
Author(s):  
Chan Zheng ◽  
Xiao Yun Ye ◽  
Xue Qing Xiao
Keyword(s):  
Nonlinear Absorption ◽  
Laser Pulses ◽  
Phase Method ◽  
Saturable Absorption ◽  
Reverse Saturable Absorption ◽  
Colloidal Nanoparticles ◽  
Free Carrier Absorption ◽  
Absorption Properties ◽  
Liquid Phase Method ◽  
Carrier Absorption

Spherical gold colloidal nanoparticles were prepared used traditional liquid phase method and the corresponding nonlinear absorption properties were investigated by open aperture Z-scan technique using 8 ns laser pulses of 532 nm. The gold colloidal nanoparticles exhibited a transform from saturable absorption (SA) to reverse saturable absorption (RSA) at relatively higher irradiation intensities. The SA behavior presumably owes to the bleach of ground-state surface plasmon resonance (SPR) absorption, while the RSA might result from high excited-stated free carrier absorption.

4-QAM OFDM Data Switching via Free Carrier Absorption in Si-Rich SiC Waveguide

2021 ◽  
Vol 27 (3) ◽  
pp. 1-11
Author(s):  
Yen-Wei Hsueh ◽  
Chih-Hsien Cheng ◽  
Cai-Syuan Fu ◽  
Huai-Yung Wang ◽  
Bo-Ji Huang ◽  
...  
Keyword(s):  
Free Carrier ◽  
Free Carrier Absorption ◽  
Carrier Absorption ◽  
Data Switching

scholarly journals Ag Nanoparticles Sensitized In2O3 Nanograin for the Ultrasensitive HCHO Detection at Room Temperature

2019 ◽  
Vol 14 (1) ◽  
Author(s):  
Shiqiang Zhou ◽  
Mingpeng Chen ◽  
Qingjie Lu ◽  
Yumin Zhang ◽  
Jin Zhang ◽  
...  
Keyword(s):  
Indoor Air ◽  
Ag Nanoparticles ◽  
Room Temperature ◽  
Unsolved Problem ◽  
Air Pollutant ◽  
Ag Nps ◽  
Performance Targets ◽  
Fabrication Cost ◽  
Low Concentrations ◽  
Stringent Performance

AbstractFormaldehyde (HCHO) is the main source of indoor air pollutant. HCHO sensors are therefore of paramount importance for timely detection in daily life. However, existing sensors do not meet the stringent performance targets, while deactivation due to sensing detection at room temperature, for example, at extremely low concentration of formaldehyde (especially lower than 0.08 ppm), is a widely unsolved problem. Herein, we present the Ag nanoparticles (Ag NPs) sensitized dispersed In2O3 nanograin via a low-fabrication-cost hydrothermal strategy, where the Ag NPs reduces the apparent activation energy for HCHO transporting into and out of the In2O3 nanoparticles, while low concentrations detection at low working temperature is realized. The pristine In2O3 exhibits a sluggish response (Ra/Rg = 4.14 to 10 ppm) with incomplete recovery to HCHO gas. After Ag functionalization, the 5%Ag-In2O3 sensor shows a dramatically enhanced response (135) with a short response time (102 s) and recovery time (157 s) to 1 ppm HCHO gas at 30 °C, which benefits from the Ag NPs that electronically and chemically sensitize the crystal In2O3 nanograin, greatly enhancing the selectivity and sensitivity.

Microscopic FCA System for Depth-Resolved Carrier Lifetime Measurement in SiC

2018 ◽  
Vol 924 ◽  
pp. 269-272 ◽  
Author(s):  
Shinichi Mae ◽  
Takeshi Tawara ◽  
Hidekazu Tsuchida ◽  
Masashi Kato
Keyword(s):  
Carrier Lifetime ◽  
Laser Light ◽  
Probe Laser ◽  
Free Carrier Absorption ◽  
Cross Sectional ◽  
Lifetime Measurements ◽  
Control Distribution ◽  
System A ◽  
Excitation Laser ◽  
Carrier Absorption

For high voltage SiC bipolar devices, carrier lifetime is an important parameter, and for optimization of device performance, we need to control distribution of the carrier lifetime in a wafer. So far, there have been limited systems for depth-resolved carrier lifetime measurements without cross sectional cut. In this study, we adopted a free carrier absorption technique and made local overlapping of the probe laser light with excitation laser light to develop depth-resolved carrier lifetime measurements. We named the developed system a microscopic FCA system and demonstrated measurement results for samples with and without intentional carrier lifetime distribution.

A study of vibrations of boron and phosphorus in silicon by infra-red absorption

1965 ◽  
Vol 287 (1408) ◽  
pp. 64-88 ◽  
Keyword(s):  
Second Harmonic ◽  
Force Constants ◽  
Published Data ◽  
Free Carrier Absorption ◽  
Local Modes ◽  
Pure Silicon ◽  
Infra Red ◽  
Carrier Absorption ◽  
Experimental Problem ◽  
Silicon Doped

The infra-red absorption spectrum of silicon doped with high densities of boron and phosphorus has been measured from 1 to 60 μm and at temperatures between 5 and 290 °K in order to observe the local and band mode vibrational absorption activated by these impurities. The major experimental problem, that of achieving a high degree of electrical compensation to eliminate free carrier absorption, was solved by using fast electron bombardment to introduce a controllable number of trapping centres. A series of experiments was conducted to eliminate the effects of these centres from the spectrum of the chemical impurities. The characteristic spectra of the substitutional boron and phosphorus have been analysed in detail in terms of the theory of Dawber & Elliott. For local modes activated by boron isotopes close agreement with theory has been found in number of lines, strength and frequency. From the latter it is estimated that the local force constants are weakened by less than 10 % on substituting boron for silicon in the lattice. Second harmonic lines are observed at a frequency 0.25 % less than twice that of the fundamentals. The band modes exhibit a striking in-band resonance at 0.0546 eV which was not theoretically predicted. This is attributed to phosphorus and analysis shows that the theory can give such a resonance but not with parameters associated with substitutional phosphorus and unchanged force constants. Most of the remaining features in the band modes can be interpreted satisfactorily in terms of substitutional boron but this requires some modification to published data on the density of states for pure silicon. Critical points for TO( L ), TO( X ) and LA( L ) phonons are clearly identified in the spectra.

Free carrier absorption in heavily doped silicon layers

2004 ◽  
Vol 84 (13) ◽  
pp. 2265-2267 ◽  
Author(s):  
Joerg Isenberg ◽  
Wilhelm Warta
Keyword(s):  
Free Carrier ◽  
Free Carrier Absorption ◽  
Doped Silicon ◽  
Carrier Absorption ◽  
Heavily Doped

Nonlinear Optical Absorption and Related Phenomena in Liquid Crystals

2001 ◽  
Vol 709 ◽  
Author(s):  
N.V. Tabiryan ◽  
U.A. Hrozhyk ◽  
H.L. Margaryan ◽  
M.J. Mora ◽  
S.R. Nersisyan ◽  
...  
Keyword(s):  
Phase Transition ◽  
Light Scattering ◽  
Optical Absorption ◽  
Nonlinear Absorption ◽  
Nonlinear Optical ◽  
Isotropic Phase ◽  
Nonlinear Optical Absorption ◽  
Critical Opalescence ◽  
Application Potential ◽  
Large Application

SUMMARYThus, in the present paper, we reported about several processes of nonlinear absorption and transmission in dye-doped NLC: nonlinear absorption due to light induced reorientation of NLC doped by highly dichroic dyes; nonlinear transmission due to nonlinear birefringence, and self-extinguishing of the beam due to”critical opalescence,” critically enhanced light scattering at the pre-transition region of nematic-isotropic phase transition. All these processes have large application potential for laser beam control and characterization techniques.

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