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@@ -305,12 +305,12 @@ advantage is based on a broad range of optical nonlinearities, strong
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two-photon absorption, as well as a possibility of the photo-induced
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two-photon absorption, as well as a possibility of the photo-induced
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EHP excitation~\cite{leuthold2010nonlinear}. Furthermore, silicon
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EHP excitation~\cite{leuthold2010nonlinear}. Furthermore, silicon
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nanoantennas demonstrate a sufficiently high damage threshold due to
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nanoantennas demonstrate a sufficiently high damage threshold due to
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-the large melting temperature ($\approx$1690~K), whereas its nonlinear
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+the large melting temperature ($\approx 1690$K), whereas its nonlinear
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optical properties have been extensively studied during last
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optical properties have been extensively studied during last
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decays~\cite{Van1987, Sokolowski2000, leuthold2010nonlinear}. High
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decays~\cite{Van1987, Sokolowski2000, leuthold2010nonlinear}. High
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silicon melting point typically preserves structures formed from this
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silicon melting point typically preserves structures formed from this
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material up to the EHP densities on the order of the critical value
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material up to the EHP densities on the order of the critical value
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-$n_{cr} \approx 5\cdot{10}^{21}$ cm$^{-3}$ \cite{Korfiatis2007}. At
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+$N_{cr} \approx 5\cdot{10}^{21}$ cm$^{-3}$ \cite{Korfiatis2007}. At
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the critical density and above, silicon acquires metallic properties
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the critical density and above, silicon acquires metallic properties
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($Re(\epsilon) < 0$) and contributes to the EHP reconfiguration during
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($Re(\epsilon) < 0$) and contributes to the EHP reconfiguration during
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ultrashort laser irradiation.
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ultrashort laser irradiation.
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@@ -410,7 +410,7 @@ written as
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\begin{equation} \label{Dens}
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\begin{equation} \label{Dens}
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\displaystyle{\frac{\partial{N_e}}{\partial t} =
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\displaystyle{\frac{\partial{N_e}}{\partial t} =
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\frac{N_a-N_e}{N_a}\left(\frac{\sigma_1I}{\hbar\omega} +
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\frac{N_a-N_e}{N_a}\left(\frac{\sigma_1I}{\hbar\omega} +
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- \frac{\sigma_2I^2}{2\hbar\omega}\right) + \alpha{I}n_e -
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+ \frac{\sigma_2I^2}{2\hbar\omega}\right) + \alpha{I}N _e -
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\frac{C\cdot{N_e}^3}{C\tau_{rec}N_e^2+1},} \end{equation} where
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\frac{C\cdot{N_e}^3}{C\tau_{rec}N_e^2+1},} \end{equation} where
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$I=\frac{n}{2}\sqrt{\frac{\epsilon_0}{\mu_0}}\left|\vec{E}\right|^2$
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$I=\frac{n}{2}\sqrt{\frac{\epsilon_0}{\mu_0}}\left|\vec{E}\right|^2$
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is the intensity, $\sigma_1 = 1.021\cdot{10}^3$ cm$^{-1}$ and
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is the intensity, $\sigma_1 = 1.021\cdot{10}^3$ cm$^{-1}$ and
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@@ -424,12 +424,12 @@ $\alpha = 21.2$ cm$^2$/J is the avalanche ionization coefficient
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\cite{Pronko1998} at the wavelength $800$ nm in air. As we have noted,
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\cite{Pronko1998} at the wavelength $800$ nm in air. As we have noted,
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free carrier diffusion is neglected during and shortly after the laser
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free carrier diffusion is neglected during and shortly after the laser
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excitation \cite{Van1987, Sokolowski2000}. In particular, from the
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excitation \cite{Van1987, Sokolowski2000}. In particular, from the
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-Einstein formula $D = k_B T_e \tau/m^*$ $\approx$ (1-2)10$^5$ m/s
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-(k$_B$ is the Boltzmann constant, T$_e$ is the electron temperature,
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-$\tau$=1~\textit{fs} is the collision time, $m^*$ = 0.18$m_e$ is the effective
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-mass), where T$_e$ $\approx$ 2*10$^4$~K for N$_e$ close to N$_cr$. It
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+Einstein formula $D = k_B T_e \tau/m^* \approx (1-2){10}^5$ m/s
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+($k_B$ is the Boltzmann constant, $T_e$ is the electron temperature,
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+$\tau=1$~\textit{fs} is the collision time, $m^* = 0.18 m_e$ is the effective
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+mass), where $T_e \approx 2*{10}^4$ K for $N_e$ close to $N_{cr}$. It
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means that during the pulse duration ($\approx$ 50~\textit{fs}) the diffusion
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means that during the pulse duration ($\approx$ 50~\textit{fs}) the diffusion
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-length will be around 5--10~nm for N$_e$ close to N$_cr$.
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+length will be around 5--10~nm for $N_e$ close to $N_{cr}$.
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\begin{figure}[ht!]
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\begin{figure}[ht!]
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\centering
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\centering
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@@ -618,7 +618,7 @@ license.
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is, the higher the NP asymmetry $G_{N_e}$ is achieved.
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is, the higher the NP asymmetry $G_{N_e}$ is achieved.
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\textit{'Stage 2'} corresponds to further electric field oscillations
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\textit{'Stage 2'} corresponds to further electric field oscillations
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- (t$\approx$2--15) leading to unstationery nature of the EHP evolution
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+ ($t \approx 2--15$) leading to unstationery nature of the EHP evolution
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with a maximum of the EHP distribution on the front side of the Si NP
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with a maximum of the EHP distribution on the front side of the Si NP
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owing to starting excitation of MD and MQ resonances, requiring more
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owing to starting excitation of MD and MQ resonances, requiring more
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time to be excited. At this stage, density of EHP ($< 10^{20}$cm$^2$)
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time to be excited. At this stage, density of EHP ($< 10^{20}$cm$^2$)
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@@ -668,7 +668,7 @@ license.
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achieved below the magnetic dipole resonant conditions for $R < 100$
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achieved below the magnetic dipole resonant conditions for $R < 100$
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nm. Thus, the EHP distribution in Fig.~\ref{fig2}(c) is optimal for
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nm. Thus, the EHP distribution in Fig.~\ref{fig2}(c) is optimal for
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symmetry breaking in Si NP, as it results in the larger asymmetry
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symmetry breaking in Si NP, as it results in the larger asymmetry
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- factor $G_{N_e}$ and higher electron densities $n_e$. We stress here
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+ factor $G_{N_e}$ and higher electron densities $N_e$. We stress here
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that such regime could be still safe for NP due to the very small
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that such regime could be still safe for NP due to the very small
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volume where such high EHP density is formed.
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volume where such high EHP density is formed.
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