Probing Surfaces and Interfaces of Solid Materials with Linear and Nonlinear Optical Techniques
朱教授曾報告線性光學技術部分，本次報告重點介紹非線性光學技術部分。
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時間：
10月31日（周三）下午3：00
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地點：
物理大樓西312會議室
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朱湘東教授簡曆：
現任加州大學戴維斯分校物理系教授。1982年本科畢業于beat365物理系。1981年入加州大學伯克利分校攻讀實驗凝聚态物理。1989年獲物理博士。同年受聘于加州大學戴維斯分校物理系做助教授。1993年升副教授。1998年升正教授。2001年起任中科院物理所光學實驗室客座教授。2007年選入美國物理學會會士（Fellow
of American Physical Society）。2011年選入美國光學學會會士（Fellow of Optical Society
of America）。
多年從事表面物理和光學物理方面的工作。從2000年開始生物物理方面的工作。主要發明了一種特殊的橢偏測量方法（光反射差法）并以此為基礎開發了一個高通量，無标記的生物化學反應測量平台。此平台被用于分子生物物理和生物化學方面的基本研究和小分子及生物醫藥開發。最近兩年發明了斜入射Sagnac光幹射方法，并開始用這個實驗方法研究非常态固體材料包括拓撲絕緣體裡表征固體相的磁特征磁和微磁測量。
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Abstract：
Surfaces and interfaces of solid materials that consist of only a few
atomic or molecular layers are a unique class of materials by
themselves. Understanding properties of surfaces and interfaces is
crucial from a number of standpoints. All forms of material synthesis
and processing start at a solid surface, they are thus controlled by
atomistic and molecular processes that occur at the surface. As physical
dimensions of building blocks of solid-state devices continue to
decrease down to a few nanometers, properties of the devices made of
these nano-materials are significantly influenced by structural,
electronic and transport properties of the surface that are distinct
from those of the bulk. This is because the surface possesses different
symmetries as required by its distinct physical setting. Furthermore, an
interface separating two materials often hosts localized states with
properties not found in either of the bulk materials such as classical
surface plasmon polaritons in the vicinity of a metal surface, surface
states on a topological insulator (driven by abrupt change in
topological order parameter), and conducting states at the interface
between polar and non-polar insulators (driven by polarization
catastrophe).
Measuring various properties of a solid surface by analyzing rich
information in light reflection from the solid has many advantages such
as non-invasiveness, in-situ detection (seeing it as it happens), access
to deeply buried interfaces, being immune to volatile material synthesis
and processing environments such as under high pressures and in liquid.
Yet optical reflection from a solid surface contains an overwhelmingly
large contribution from the bulk of the solid that needs to be
suppressed. In this presentation, I show how one can characterize a
solid surface or an interface with light reflection by taking advantage
of various symmetry-breaking effects that dramatically reduces the
contribution from the bulk. The symmetries include point-group symmetry,
translational symmetry, time-reversal symmetry, and even
s/p-polarization symmetry.
