From 58a5425154d4d7eec55463e5e2a89b7ade067781 Mon Sep 17 00:00:00 2001 From: Blaise Thompson Date: Sun, 15 Apr 2018 17:04:18 -0500 Subject: 2018-04-15 17:04 --- spectroscopy/auto/chapter.el | 3 +- spectroscopy/chapter.tex | 152 +++++++++++++++++++++---------------------- 2 files changed, 76 insertions(+), 79 deletions(-) (limited to 'spectroscopy') diff --git a/spectroscopy/auto/chapter.el b/spectroscopy/auto/chapter.el index 731ac34..41829c0 100644 --- a/spectroscopy/auto/chapter.el +++ b/spectroscopy/auto/chapter.el @@ -3,7 +3,6 @@ (lambda () (LaTeX-add-labels "cha:spc" - "spc:eqn:E" - "spc:fig:ranges")) + "spc:eqn:E")) :latex) diff --git a/spectroscopy/chapter.tex b/spectroscopy/chapter.tex index 819fe94..805bce8 100644 --- a/spectroscopy/chapter.tex +++ b/spectroscopy/chapter.tex @@ -38,7 +38,7 @@ many photons. % The basics of light matter interaction have been covered in many texts. % For a beginners introduction I recommend ``How a Photon is Created or Absorbed'' by -\textref{HendersonGiles1994a}. % +\textcite{HendersonGiles1994a}. % Here I present a very minimal overview. % Consider a two state system: ``a'' and ``b''. % @@ -61,8 +61,8 @@ For simplicity, we consider a single transition dipole, $\mu$. % The Hamiltonian which controls the coupling of or simple system to the electric field described in \autoref{spc:eqn:E} can be written. % \begin{eqnarray} - H &=& H_{0} - \mu \cdot E \\ - &=& H_{0} - \mu \cdot \frac{E^0}{2}\left[ \me^{i(kz-\omega t)} + \me^{-i(kz-\omega t)} \right] + H &=& H_{0} + \mu \cdot E \\ + &=& H_{0} + \mu \cdot \frac{E^0}{2}\left[ \me^{i(kz-\omega t)} + \me^{-i(kz-\omega t)} \right] \end{eqnarray} Solving for the time-dependent coefficients, then: @@ -79,15 +79,11 @@ Where $\omega_a$ and $\omega_b$ are the fast (and familiar) Bohr frequencies and In Dirac notation \cite{DiracPaulAdrienMaurice1939a}, an observable (such as $\mu(t)$) can be written simply: % \begin{equation} - \mu(t) = \left< c_aa + c_bb \left| \hat{H} \right| c_aa + c_bb \right> + \mu(t) = |c_a(t)|^2 \langle \phi_a | \mu | \phi_a \rangle + |c_b(t)|^2 \langle \phi_b | \mu | \phi_b \rangle + c_a(t) c_b^*(t) \langle \phi_b | \mu | \phi_a \rangle + + c_b(t) c_a^*(t) \langle \phi_a | \mu | \phi_b \rangle \end{equation} The complex wavefunction is called a \emph{ket}, represented $\left|b\right>$. % The complex conjugate is called a \emph{bra}, represented $\left + - \left -\end{equation} The first two terms are populations and the final two terms are coherences. % The coherent terms will evolve with the rapid Bohr oscillations, coupling the dipole observable with the time-dependent electric field. % @@ -146,18 +142,19 @@ These are workhorse experiments, like absorbance, reflectance, FTIR, UV-Vis, and ordinary Raman spectroscopy (COORS). % These experiments are incredibly robust, and are typically performed using easy to use commercial desktop instruments. % -There are now even handheld Raman spectrometers for use in industrial settings. [CITE] % +There are now even handheld Raman spectrometers for use in industrial settings. \cite{nanoram} % Multidimensional spectroscopy contains a lot more information about the material under investigation. % In this work, by ``multidimensional'' I mean higher-order spectroscopy. % -I ignore ``correlation spectroscopy'' [CITE], which tracks linear spectral features against -non-spectral dimensions like lab time, pressure, and temperature. % +I ignore ``correlation spectroscopy'' (otherwise known as covariance spectroscopy), which tracks +linear spectral features against non-spectral dimensions like lab time, pressure, and +temperature. % So, in the context of this dissertation, multidimensional spectroscopy is synonymous with nonlinear spectroscopy. % Nonlinear spectroscopy relies upon higher-order terms in the light-matter interaction. In a generic -system, each term is roughly ten times smaller than the last. % TODO: cite? +system, a rule of thumb states that each term is roughly ten times smaller than the last. % This means that nonlinear spectroscopy is typically very weak. % Still, nonlinear signals are fairly easy to isolate and measure using modern instrumentation, as this dissertation describes. % @@ -261,67 +258,68 @@ space. % Since signal goes as $N^2$, signal decays much faster in homodyne-collected experiments. % If signal decays as a single exponential, the extracted decay is twice as fast for homodyne vs heterodyne-detected data. % -[CITE DARIEN CORRECTION] - -\section{Instrumentation} % ====================================================================== - -In this section I introduce the key components of the MR-CMDS instrument. % -This also serves to introduce the reader to the particular components used in my research. % - -\subsection{LASER} % ----------------------------------------------------------------------------- - -Light Amplified by Stimulated Emission of Radiation (LASER) light sources are absolutely crucial -components of the modern MR-CMDS instrument. % -The first laser was built in 1960 by \textcite{MaimanTheodore1960a}, and pulsed lasers were -invented soon after. % -Today, ultrafast light sources are relatively cheap and reliable. % -Our SpectraPhysics ``Tsunami'' oscillator uses passive Kerr-lens mode-locking to generate $\sim$35 -fs seed pulses at $\sim$80 MHz (one pulse every 12.5 nanoseconds). \cite{Tsunami} % -This seed is split and fed into two 1 KHz amplifiers, a picosecond ``Spitfire Ace'' -\cite{SpitfireAce} and a femtosecond ``Spitfire Pro'' \cite{SpitfirePro}. % -These amplifiers each output several watts of ultrafast pulses at 1 KHz (one pulse per -millisecond). % - -\subsection{Optical parametric amplifiers} % ----------------------------------------------------- - -Optical Parametric Amplifiers (OPAs) are arguably the most crucial component of modern MR-CMDS, as -they provide the frequency tunable light sources that we require. \cite{CerulloGiulio2003a} % -OPAs provide tunability through three-wave sum and difference frequency generation processes. % -``Fundamental'' tunability is achieved by splitting the 800 nm photons into two lower energy -photons, with a splitting ratio determined by motorized optics. % -These split photons are called ``signal'' and ``idler'', with signal being the higher energy and -idler the lower energy photon. % - -% TODO: paragraph about phase matching conditions and polarization - -Signal and idler are then either used directly, or amplified through sum or difference frequency -processes to provide broadband tuneability. % -All available optical processes for the TOPAS-C OPAs \cite{TOPAS-C} used on the femtosecond table -are shown in \autoref{spc:fig:ranges}. % -Amazingly, these OPAs offer tunability from the mid-infrared to the ultraviolet. % -Currently we do not have proper automated filters to make it possible to continuously scan between -regions, but such things are possible. % - -On the picosecond table we have three separate kinds of OPAs, including one TOPAS-800 -\cite{TOPAS-800} and two OPA-800 models that have been modified with precision micro control -\cite{PMC} servo motors to provide automated tunability. % - -\subsection{Delay stages} % ---------------------------------------------------------------------- - -Delay stages are simple, one-motor devices which are used to control the relative arrival time of -pulses at the sample. % -The Wright Group currently owns four models of delay stage: 1. Newport MFA-CC [CITE], 2. Aerotech -... [CITE], 3. Thorlabs LTS300 [CITE]. % -The fourth ``model'' are actually homemade stages that are driven using PMC motors. % - -\subsection{Spectrometers} % --------------------------------------------------------------------- - -Spectrometers... - -\begin{figure} - \includegraphics[width=\linewidth]{spectroscopy/ranges} - \caption{ - CAPTION TODO - } - \label{spc:fig:ranges} -\end{figure} \ No newline at end of file +This fact is often forgotten, and papers have been corrected for forgetting this factor of +two. \cite{KoivistoinenJuha2017a} % + +% \section{Instrumentation} % ====================================================================== + +% In this section I introduce the key components of the MR-CMDS instrument. % +% This also serves to introduce the reader to the particular components used in my research. % + +% \subsection{LASER} % ----------------------------------------------------------------------------- + +% Light Amplified by Stimulated Emission of Radiation (LASER) light sources are absolutely crucial +% components of the modern MR-CMDS instrument. % +% The first laser was built in 1960 by \textcite{MaimanTheodore1960a}, and pulsed lasers were +% invented soon after. % +% Today, ultrafast light sources are relatively cheap and reliable. % +% Our SpectraPhysics ``Tsunami'' oscillator uses passive Kerr-lens mode-locking to generate $\sim$35 +% fs seed pulses at $\sim$80 MHz (one pulse every 12.5 nanoseconds). \cite{Tsunami} % +% This seed is split and fed into two 1 KHz amplifiers, a picosecond ``Spitfire Ace'' +% \cite{SpitfireAce} and a femtosecond ``Spitfire Pro'' \cite{SpitfirePro}. % +% These amplifiers each output several watts of ultrafast pulses at 1 KHz (one pulse per +% millisecond). % + +% \subsection{Optical parametric amplifiers} % ----------------------------------------------------- + +% Optical Parametric Amplifiers (OPAs) are arguably the most crucial component of modern MR-CMDS, as +% they provide the frequency tunable light sources that we require. \cite{CerulloGiulio2003a} % +% OPAs provide tunability through three-wave sum and difference frequency generation processes. % +% ``Fundamental'' tunability is achieved by splitting the 800 nm photons into two lower energy +% photons, with a splitting ratio determined by motorized optics. % +% These split photons are called ``signal'' and ``idler'', with signal being the higher energy and +% idler the lower energy photon. % + +% % TODO: paragraph about phase matching conditions and polarization + +% Signal and idler are then either used directly, or amplified through sum or difference frequency +% processes to provide broadband tuneability. % +% All available optical processes for the TOPAS-C OPAs \cite{TOPAS-C} used on the femtosecond table +% are shown in \autoref{spc:fig:ranges}. % +% Amazingly, these OPAs offer tunability from the mid-infrared to the ultraviolet. % +% Currently we do not have proper automated filters to make it possible to continuously scan between +% regions, but such things are possible. % + +% On the picosecond table we have three separate kinds of OPAs, including one TOPAS-800 +% \cite{TOPAS-800} and two OPA-800 models that have been modified with precision micro control +% \cite{PMC} servo motors to provide automated tunability. % + +% \subsection{Delay stages} % ---------------------------------------------------------------------- + +% Delay stages are simple, one-motor devices which are used to control the relative arrival time of +% pulses at the sample. % +% The Wright Group currently owns four models of delay stage: 1. Newport MFA-CC [CITE], 2. Aerotech +% ... [CITE], 3. Thorlabs LTS300 [CITE]. % +% The fourth ``model'' are actually homemade stages that are driven using PMC motors. % + +% \subsection{Spectrometers} % --------------------------------------------------------------------- + +% Spectrometers... + +% \begin{figure} +% \includegraphics[width=\linewidth]{spectroscopy/ranges} +% \caption{ +% CAPTION TODO +% } +% \label{spc:fig:ranges} +% \end{figure} \ No newline at end of file -- cgit v1.2.3