Nonlinear absorption in silicon nanocrystals

The nonlinear absorption of light in silicon nanocrystals suspended in glycerol is studied by the Z-scan method. The experimental data are used for calculating the nonlinear absorption coefficient {beta}{sub Si-gl} for silicon nanocrystals in glycerol (with a volume filling factor f=2x10{sup -4}), a...

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Bibliographic Details
Published inQuantum electronics (Woodbury, N.Y.) Vol. 31; no. 9; pp. 817 - 820
Main Authors Korovin, S B, Orlov, A N, Prokhorov, A M, Pustovoi, V I, Konstantaki, M, Couris, S, Koudoumas, E
Format Journal Article
LanguageEnglish
Published United States IOP Publishing 30.09.2001
Subjects
ABSORPTION
ALCOHOLS
CARRIERS
CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY
DATA
ELECTRIC FIELDS
ELECTROMAGNETIC RADIATION
ELECTRONS
ELEMENTARY PARTICLES
ELEMENTS
EXPERIMENTAL DATA
FERMIONS
GLYCEROL
HYDROXY COMPOUNDS
INFORMATION
LASER RADIATION
LEPTONS
NANOSCIENCE AND NANOTECHNOLOGY
NANOSTRUCTURES
NONLINEAR PROBLEMS
NUMERICAL DATA
ORGANIC COMPOUNDS
PULSES
RADIATIONS
RAMAN EFFECT
SEMIMETALS
SILICON
SORPTION
SPECTRA
WAVELENGTHS
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Summary:The nonlinear absorption of light in silicon nanocrystals suspended in glycerol is studied by the Z-scan method. The experimental data are used for calculating the nonlinear absorption coefficient {beta}{sub Si-gl} for silicon nanocrystals in glycerol (with a volume filling factor f=2x10{sup -4}), and the coefficient {beta}{sub Si} for pure silicon with a hypothetical volume filling factor f{approx}1. For the laser radiation wavelength {lambda}=497 nm and the pulse duration {tau}=0.5 ns, these coefficients are {beta}{sub Si-gl}=1.2x10{sup -8} cm W{sup -1} and {beta}{sub Si} =7.36x10{sup -5} cm W{sup -1}, while the corresponding values for {lambda}=532 nm and {tau}=10 ns are {beta}{sub Si-gl}=5.36x10{sup -5} cm W{sup -1} and {beta}{sub Si} =0.25 cm W{sup -1}. Experiments with 540-nm, 20-ps laser pulses performed for two different filling factors equal to 2x10{sup -4} and 3x10{sup -3} gave nonlinear absorption coefficients {beta}{sub Si-gl}=2x10{sup -7} and 3.6x10{sup -6} cm W{sup -1}, respectively. Optical absorption and Raman scattering spectra of silicon nanocrystals are also studied. A theoretical analysis of the experimental results shows that optical absorption can be related to the localisation of photoexcited carriers in the conduction band. The localisation is caused by the action of strong static electric fields on an electron in a nanoparticle. (nonlinear optical phenomena)
ISSN:1063-7818
1468-4799
DOI:10.1070/QE2001v031n09ABEH002052