replace fs

main.tex

@@ -236,7 +236,7 @@ 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
 inhomogeneous carrier distribution. To reveal and study this effect, we
  perform a full-wave numerical simulation of the intense
-femtosecond (fs) 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)
 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
@@ -313,7 +313,7 @@ To account for the material ionization that is induced by a sufficiently intense
 % \begin{figure*}[ht!]
 % \centering
 % \includegraphics[width=120mm]{fig2.png}
-% \caption{\label{fig2} Free carrier density snapshots of electron plasma evolution inside Si nanoparticle taken a) $30$ fs b) $10$ fs before the pulse peak, c) at the pulse peak, d) $10$ fs e) $30$ fs after the pulse peak. Pulse duration $50$ fs (FWHM). Wavelength $800$ nm in air. Radius of the nanoparticle $R \approx 105$ nm, corresponding to the resonance condition. Graph shows the dependence of the asymmetric parameter of electron plasma density on the average electron density in the front half of the nanoparticle. $n_{cr} = 5\cdot{10}^{21}$ cm$^{-3}$ is the critical plasma resonance electron density for silicon.}
+% \caption{\label{fig2} Free carrier density snapshots of electron plasma evolution inside Si nanoparticle taken a) $30\:f\!s$  b) $10\:f\!s$ before the pulse peak, c) at the pulse peak, d) $10\:f\!s$ e) $30\:f\!s$  after the pulse peak. Pulse duration $50\:f\!s$ (FWHM). Wavelength $800$ nm in air. Radius of the nanoparticle $R \approx 105$ nm, corresponding to the resonance condition. Graph shows the dependence of the asymmetric parameter of electron plasma density on the average electron density in the front half of the nanoparticle. $n_{cr} = 5\cdot{10}^{21}$ cm$^{-3}$ is the critical plasma resonance electron density for silicon.}
 % \end{figure*}
 
 
@@ -456,7 +456,7 @@ relaxation time of high electron density in silicon is $\tau_{rec} =
 6\cdot{10}^{-12}$ s \cite{Yoffa1980}, therefore, the
 electron density will not have time to decrease significantly for
 subpicosecond pulse separations. In our simulations, we use $\delta{t}
-= 200$ fs pulse separation. The intensity distributions near the
+= 200\:f\!s$ pulse separation. The intensity distributions near the
 silicon nanoparticle of $R = 95$ nm, corresponding to maxima value of
 $K$ optimization factor, without plasma and with generated plasma are
 shown in Fig. \ref{fig4}. The intensity distribution is strongly
@@ -468,7 +468,7 @@ Fig. \ref{fig4}(b). Therefore, the generated nanoplasma acts like a quasi-metall
 % \begin{figure}[ht] \centering
 % \includegraphics[width=90mm]{fig4.png}
 % \caption{\label{fig4} a) Electron plasma distribution inside Si
-% nanoparticle $R \approx 95$ nm $50$ fs after the pulse peak; (Kostya: Is it scattering field intensity snapshot  XXX fs after the second pulse maxima passed the particle?) Intensity
+% nanoparticle $R \approx 95$ nm $50\:f\!s$ after the pulse peak; (Kostya: Is it scattering field intensity snapshot  $XXX\:f\!s$ after the second pulse maxima passed the particle?) Intensity
 % distributions around and inside the nanoparticle b) without plasma, c)
 % with electron plasma inside.}
 % \end{figure}
@@ -490,9 +490,8 @@ like this: Small size will give as a magnetic dipole b1 resonance with
 Q-factor (ratio of wavelength to the resonance width at half-height)
 of about 8, a1 Q approx 4, the larger particle will have b2 Q approx
 40. For large particle we will have e.g. at R=238.4 second order b4
-resonance with Q approx 800.  As soon as the period at WL=800nm is 2.6
-fs, we need about 25 fs pulse to pump dipole response, about 150 fs
-for quadrupole, and about 2000fs for b4. If we think of optical
+resonance with Q approx 800.  As soon as the period at WL=800nm is $2.6\:f\!s$, we need about $25\:f\!s$ pulse to pump dipole response, about $150\:f\!s$
+for quadrupole, and about $2000\:f\!s$ for b4. If we think of optical
 switching applications this is a rise-on time.
 
 TODO Kostya: Add discussion about mode selection due to the formation