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small modif

Tatiana Itina 8 years ago
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commit
1dabee0e25
1 changed files with 24 additions and 15 deletions
  1. 24 15
      main.tex

+ 24 - 15
main.tex

@@ -215,11 +215,11 @@ baranov2016nonlinear, baranov2016tuning} and
 metasurfaces~\cite{iyer2015reconfigurable, shcherbakov2015ultrafast,
 metasurfaces~\cite{iyer2015reconfigurable, shcherbakov2015ultrafast,
 yang2015nonlinear}.
 yang2015nonlinear}.
 
 
-In all this works on all-dielectric nonlinear nanostructures, the
+In these works on all-dielectric nonlinear nanostructures, the
 building blocks (nanoparticles) were considered as objects with
 building blocks (nanoparticles) were considered as objects with
 dielectric permittivity homogeneously distributed over
 dielectric permittivity homogeneously distributed over
-nanoparticle. Therefore, in order to manipulate by propagation angle
-of transmitted light it is necessary to use complicated nanostructures
+nanoparticle. Therefore, in order to manipulate the propagation angle
+of the transmitted light it is necessary to use complicated nanostructures
 with reduced symmetry~\cite{albella2015switchable, baranov2016tuning,
 with reduced symmetry~\cite{albella2015switchable, baranov2016tuning,
 shibanuma2016unidirectional}.
 shibanuma2016unidirectional}.
 
 
@@ -236,16 +236,16 @@ In this Letter, we show that ultra-short laser-based EHP photo-excitation in
 a spherical semiconductor (e.g., silicon) nanoparticle leads to a strongly
 a spherical semiconductor (e.g., silicon) nanoparticle leads to a strongly
 inhomogeneous carrier distribution. To reveal and study this effect, we
 inhomogeneous carrier distribution. To reveal and study this effect, we
  perform a full-wave numerical simulation of the intense
  perform a full-wave numerical simulation of the intense
-femtosecond ($f\!s$) laser pulse interaction with a silicon
+femtosecond ($\,f\!s$) laser pulse interaction with a silicon
 nanoparticle supporting Mie resonances and two-photon free carrier generation. In particular, we couple finite-difference time-domain (FDTD)
 nanoparticle supporting Mie resonances and two-photon free carrier generation. In particular, we couple finite-difference time-domain (FDTD)
 method used to solve  Maxwell equations with kinetic equations describing
 method used to solve  Maxwell equations with kinetic equations describing
 nonlinear EHP generation.  Three-dimensional transient variation of the material dielectric permittivity is calculated for nanoparticles of several sizes. The obtained results propose a novel strategy to create
 nonlinear EHP generation.  Three-dimensional transient variation of the material dielectric permittivity is calculated for nanoparticles of several sizes. The obtained results propose a novel strategy to create
 complicated non-symmetrical nanostructures by using  photo-excited
 complicated non-symmetrical nanostructures by using  photo-excited
-single spherical silicon nanoparticles. Moreover, we show that dense EHP can
+single spherical silicon nanoparticles. Moreover, we show that a dense EHP can
 be generated at deeply subwavelength scale
 be generated at deeply subwavelength scale
-($\approx$$\lambda$$^3$/100) supporting formation of small metalized
-parts inside the nanoparticle, which transforms all-dielectric
-nanoparticle to a hybrid one that extends functionality of the ultrafast
+($\approx$$\lambda$$^3$/100) supporting the formation of small metalized
+parts inside the nanoparticle. In fact, such effects transform an all-dielectric
+nanoparticle to a hybrid one strongly extending functionality of the ultrafast
 optical nanoantennas.
 optical nanoantennas.
 
 
 
 
@@ -272,7 +272,7 @@ optical nanoantennas.
 \section{Modeling details}
 \section{Modeling details}
  
  
 
 
-We focus out attention on silicon because this material is promising
+We focus attention on silicon because this material is promising
 for the implementation of numerous nonlinear photonic devices. This advantage is based on a broad
 for the implementation of numerous nonlinear photonic devices. This advantage is based on a broad
 range of optical nonlinearities, strong two-photon absorption, as well as a possibility of the photo-induced EHP
 range of optical nonlinearities, strong two-photon absorption, as well as a possibility of the photo-induced EHP
 excitation~\cite{leuthold2010nonlinear}. Furthermore, silicon
 excitation~\cite{leuthold2010nonlinear}. Furthermore, silicon
@@ -309,7 +309,7 @@ where $\theta$ is the temporal pulse width at the half maximum (FWHM), $t_0$ is
 
 
 \subsection{Material ionization}
 \subsection{Material ionization}
 
 
-To account for the material ionization that is induced by a sufficiently intense laser field inside the particle, we couple Maxwell's equations with the kinetic equation for the electron-hole plasma as follows
+To account for the material ionization that is induced by a sufficiently intense laser field inside the particle, we couple Maxwell's equations with the kinetic equation for the electron-hole plasma as described below.
 % \begin{figure*}[ht!]
 % \begin{figure*}[ht!]
 % \centering
 % \centering
 % \includegraphics[width=120mm]{fig2.png}
 % \includegraphics[width=120mm]{fig2.png}
@@ -331,10 +331,22 @@ where $I=\frac{n}{2}\sqrt{\frac{\epsilon_0}{\mu_0}}\left|\vec{E}\right|^2$ is th
 \begin{tabular*}{0.76\textwidth}{ c@{\extracolsep{\fill}} c@{\extracolsep{\fill}} c@{\extracolsep{\fill}} c@{\extracolsep{\fill}} c}
 \begin{tabular*}{0.76\textwidth}{ c@{\extracolsep{\fill}} c@{\extracolsep{\fill}} c@{\extracolsep{\fill}} c@{\extracolsep{\fill}} c}
 $-80\:f\!s$&$-60\:f\!s$&$-30\:f\!s$&$ -20\:f\!s$&$ -10\:f\!s$\\
 $-80\:f\!s$&$-60\:f\!s$&$-30\:f\!s$&$ -20\:f\!s$&$ -10\:f\!s$\\
 \end{tabular*}
 \end{tabular*}
+{\setlength\topsep{-1pt}
+\begin{flushleft}
+$R=75$~nm
+\end{flushleft}}
 \includegraphics[width=0.9\textwidth]{2nm_75}
 \includegraphics[width=0.9\textwidth]{2nm_75}
+{\setlength\topsep{-1pt}
+\begin{flushleft}
+$R=100$~nm
+\end{flushleft}}
 \includegraphics[width=0.9\textwidth]{2nm_100}
 \includegraphics[width=0.9\textwidth]{2nm_100}
+{\setlength\topsep{-1pt}
+\begin{flushleft}
+$R=115$~nm
+\end{flushleft}}
 \includegraphics[width=0.9\textwidth]{2nm_115}
 \includegraphics[width=0.9\textwidth]{2nm_115}
-\caption{\label{plasma-105nm} Evolution of lectron density $n_e$ (using $10^{\,20} \ {\rm cm}^{-3}$ units) for  (a--e)~$R=75$, (f--j)~$R=100$~nm, and (k--o)~$R=115$~nm. Gaussian pulse duration $80\:f\!s$, snapshot are taken before the pulse maxima, the corresponding time-shifts are shown in the top of each column.}
+\caption{\label{plasma-105nm} Evolution of electron density $n_e$ (using $10^{\,20} \ {\rm cm}^{-3}$ units) for  (a$\,$--$\,$e)~$R=75$~nm, (f$\,$--$\,$j$\,$)~$R=100$~nm, and ($\,$k$\,$--$\,$o)~$R=115$~nm. Gaussian pulse duration $80\:f\!s$, snapshots are taken before the pulse maxima, the corresponding time-shifts are shown in the top of each column. Laser irradiation fluences are (a-e) $0.12$ J/cm$^2$, (f-o) $0.16$ J/cm$^2$.}
 \end{figure*}
 \end{figure*}
 
 
 The changes of the real and imaginary parts of the permittivity associated with the time-dependent free carrier response \cite{Sokolowski2000} can be derived from equations (\ref{Maxwell}, \ref{Drude}) and are written as follows
 The changes of the real and imaginary parts of the permittivity associated with the time-dependent free carrier response \cite{Sokolowski2000} can be derived from equations (\ref{Maxwell}, \ref{Drude}) and are written as follows
@@ -384,10 +396,7 @@ electron densities $n_e$. We stress here that such regime
 could be still safe for nanoparticle due to the very small volume where such high
 could be still safe for nanoparticle due to the very small volume where such high
 EHP density is formed. 
 EHP density is formed. 
 
 
-TODO: need to discuss this -
-Of cause, this plasma is expected to diffuse after the considered time and turn to the homogeneously distributed one over the nanoparticle volume with a smaller density. Part of the electrons can also be ejected/injected into the surrounding medium, the process known to depend on the Shottky barrier at the particle border.
-
-\subsection{Effects of nanoparticle size/scattering efficiency factor
+\subsection{Effects of nanoparticle size and scattering efficiency factor
 on scattering directions}
 on scattering directions}
 
 
 % \begin{figure}[ht] \centering
 % \begin{figure}[ht] \centering