Chapter 2
Electrodynamics at Interface
Abstract This chapter deals with electrodynamic aspects of the interfacial SFG
spectroscopy. In the SFG processes, two incident light fields generate nonlinear
polarization at the interface, which in turn emits the sum-frequency signal. We delineate the whole SFG processes from macroscopic viewpoint of electromagnetics.
This theory forms a basis of the SFG spectroscopy in order to establish quantitative
relation between the nonlinear polarization at interface and the observed light fields.
The SFG spectroscopy of interface probe essentially investigates the former through
observing the latter. The present overview of the SFG processes helps us with
comprehending the essential factors in observable SFG spectra.
Keywords Maxwell equations · Boundary conditions · Fresnel factor · Source
polarization
The fundamental theory of the SFG spectroscopy consists of two aspects. One is the
macroscopic description of electrodynamic SFG process, where the incident lights
induce the nonlinear polarization at the interface which in turn generates the sum
frequency signal. Since the SFG spectroscopy investigates the nonlinear polarization
of interfaces through measuring the incident and emitted lights outside the interface,
understanding of the relation between observed lights and the source polarization at
the interface is of crucial significance in the analysis of SFG spectroscopy. The other
aspect is the microscopic theory of material properties, particularly the frequencydependent nonlinear susceptibility χ (2) ((, ω 1 , ω 2 ). This theory is necessary to
connect the observed nonlinear polarization to the microscopic structure of interfaces. This chapter deals with the former, macroscopic theory of SFG mechanism,
while the theory of material properties will be treated in the following chapters.
© Springer Nature Singapore Pte Ltd. 2018
A. Morita, Theory of Sum Frequency Generation Spectroscopy,
Lecture Notes in Chemistry 97, https://doi.org/10.1007/978-981-13-1607-4_2
13
Electrodynamics at Interface
Abstract This chapter deals with electrodynamic aspects of the interfacial SFG
spectroscopy. In the SFG processes, two incident light fields generate nonlinear
polarization at the interface, which in turn emits the sum-frequency signal. We delineate the whole SFG processes from macroscopic viewpoint of electromagnetics.
This theory forms a basis of the SFG spectroscopy in order to establish quantitative
relation between the nonlinear polarization at interface and the observed light fields.
The SFG spectroscopy of interface probe essentially investigates the former through
observing the latter. The present overview of the SFG processes helps us with
comprehending the essential factors in observable SFG spectra.
Keywords Maxwell equations · Boundary conditions · Fresnel factor · Source
polarization
The fundamental theory of the SFG spectroscopy consists of two aspects. One is the
macroscopic description of electrodynamic SFG process, where the incident lights
induce the nonlinear polarization at the interface which in turn generates the sum
frequency signal. Since the SFG spectroscopy investigates the nonlinear polarization
of interfaces through measuring the incident and emitted lights outside the interface,
understanding of the relation between observed lights and the source polarization at
the interface is of crucial significance in the analysis of SFG spectroscopy. The other
aspect is the microscopic theory of material properties, particularly the frequencydependent nonlinear susceptibility χ (2) ((, ω 1 , ω 2 ). This theory is necessary to
connect the observed nonlinear polarization to the microscopic structure of interfaces. This chapter deals with the former, macroscopic theory of SFG mechanism,
while the theory of material properties will be treated in the following chapters.
© Springer Nature Singapore Pte Ltd. 2018
A. Morita, Theory of Sum Frequency Generation Spectroscopy,
Lecture Notes in Chemistry 97, https://doi.org/10.1007/978-981-13-1607-4_2
13