<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<meta name="Generator" content="Microsoft Word 14 (filtered medium)">
<!--[if !mso]><style>v\:* {behavior:url(#default#VML);}
o\:* {behavior:url(#default#VML);}
w\:* {behavior:url(#default#VML);}
.shape {behavior:url(#default#VML);}
</style><![endif]-->
<title>Physics and Astronomy Colloquium This Thursday</title>
<style><!--
/* Font Definitions */
@font-face
{font-family:Helvetica;
panose-1:2 11 6 4 2 2 2 2 2 4;}
@font-face
{font-family:"Cambria Math";
panose-1:2 4 5 3 5 4 6 3 2 4;}
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
@font-face
{font-family:Tahoma;
panose-1:2 11 6 4 3 5 4 4 2 4;}
@font-face
{font-family:Consolas;
panose-1:2 11 6 9 2 2 4 3 2 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0in;
margin-bottom:.0001pt;
font-size:12.0pt;
font-family:"Times New Roman","serif";}
h2
{mso-style-priority:9;
mso-style-link:"Heading 2 Char";
mso-margin-top-alt:auto;
margin-right:0in;
mso-margin-bottom-alt:auto;
margin-left:0in;
font-size:18.0pt;
font-family:"Times New Roman","serif";
font-weight:bold;}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:blue;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{mso-style-priority:99;
color:purple;
text-decoration:underline;}
p.MsoPlainText, li.MsoPlainText, div.MsoPlainText
{mso-style-priority:99;
mso-style-link:"Plain Text Char";
margin:0in;
margin-bottom:.0001pt;
font-size:10.5pt;
font-family:Consolas;}
p
{mso-style-priority:99;
mso-margin-top-alt:auto;
margin-right:0in;
mso-margin-bottom-alt:auto;
margin-left:0in;
font-size:12.0pt;
font-family:"Times New Roman","serif";}
p.MsoAcetate, li.MsoAcetate, div.MsoAcetate
{mso-style-priority:99;
mso-style-link:"Balloon Text Char";
margin:0in;
margin-bottom:.0001pt;
font-size:8.0pt;
font-family:"Tahoma","sans-serif";}
p.MsoNoSpacing, li.MsoNoSpacing, div.MsoNoSpacing
{mso-style-priority:1;
margin:0in;
margin-bottom:.0001pt;
font-size:12.0pt;
font-family:"Times New Roman","serif";}
span.Heading2Char
{mso-style-name:"Heading 2 Char";
mso-style-priority:9;
mso-style-link:"Heading 2";
font-weight:bold;}
span.PlainTextChar
{mso-style-name:"Plain Text Char";
mso-style-priority:99;
mso-style-link:"Plain Text";
font-family:Consolas;}
span.BalloonTextChar
{mso-style-name:"Balloon Text Char";
mso-style-priority:99;
mso-style-link:"Balloon Text";
font-family:"Tahoma","sans-serif";}
p.Body, li.Body, div.Body
{mso-style-name:Body;
mso-style-priority:99;
margin:0in;
margin-bottom:.0001pt;
font-size:12.0pt;
font-family:"Helvetica","sans-serif";
color:black;}
p.justified, li.justified, div.justified
{mso-style-name:justified;
mso-style-priority:99;
mso-margin-top-alt:auto;
margin-right:0in;
mso-margin-bottom-alt:auto;
margin-left:0in;
font-size:12.0pt;
font-family:"Times New Roman","serif";}
span.EmailStyle26
{mso-style-type:personal;
font-family:"Calibri","sans-serif";
color:#1F497D;}
span.EmailStyle27
{mso-style-type:personal;
font-family:"Calibri","sans-serif";
color:#1F497D;}
span.EmailStyle28
{mso-style-type:personal;
font-family:"Calibri","sans-serif";
color:#1F497D;}
span.Affiliation
{mso-style-name:Affiliation;
font-family:"Times New Roman","serif";}
span.Separator
{mso-style-name:Separator;}
span.EmailStyle31
{mso-style-type:personal;
font-family:"Calibri","sans-serif";
color:#1F497D;}
span.EmailStyle32
{mso-style-type:personal;
font-family:"Calibri","sans-serif";
color:#1F497D;}
span.EmailStyle33
{mso-style-type:personal;
font-family:"Calibri","sans-serif";
color:#1F497D;}
span.EmailStyle34
{mso-style-type:personal;
font-family:"Calibri","sans-serif";
color:#1F497D;}
span.EmailStyle35
{mso-style-type:personal;
font-family:"Calibri","sans-serif";
color:#1F497D;}
span.EmailStyle36
{mso-style-type:personal;
font-family:"Calibri","sans-serif";
color:#1F497D;}
span.EmailStyle37
{mso-style-type:personal;
font-family:"Calibri","sans-serif";
color:#1F497D;}
span.EmailStyle38
{mso-style-type:personal;
font-family:"Calibri","sans-serif";
color:#1F497D;}
span.EmailStyle39
{mso-style-type:personal;
font-family:"Calibri","sans-serif";
color:#1F497D;}
span.EmailStyle40
{mso-style-type:personal;
font-family:"Calibri","sans-serif";
color:#1F497D;}
span.EmailStyle41
{mso-style-type:personal;
font-family:"Calibri","sans-serif";
color:#1F497D;}
span.EmailStyle42
{mso-style-type:personal-reply;
font-family:"Calibri","sans-serif";
color:#1F497D;}
.MsoChpDefault
{mso-style-type:export-only;
font-size:10.0pt;}
@page WordSection1
{size:8.5in 11.0in;
margin:1.0in 1.0in 1.0in 1.0in;}
div.WordSection1
{page:WordSection1;}
--></style><!--[if gte mso 9]><xml>
<o:shapedefaults v:ext="edit" spidmax="1027" />
</xml><![endif]--><!--[if gte mso 9]><xml>
<o:shapelayout v:ext="edit">
<o:idmap v:ext="edit" data="1" />
</o:shapelayout></xml><![endif]-->
</head>
<body lang="EN-US" link="blue" vlink="purple">
<div class="WordSection1">
<p class="MsoNormal"><b><span style="font-size:26.0pt;color:#0070C0">Fall 2014 Colloquium
</span></b><span style="color:#0070C0"><o:p></o:p></span></p>
<p class="MsoNormal" style="margin-bottom:12.0pt"><img width="369" height="83" id="_x0000_i1025" src="cid:image001.jpg@01CFF1C7.DB911CA0"><br>
<b><span style="color:red">Nov. 20, </span><span style="color:#00B050">Thursdays, 4-5pm in Science 127 (coffee and cookies served at 3:50pm)<br>
</span><i>All students currently enrolled in Physics 401 and 501 are required to attend all colloquia<o:p></o:p></i></b></p>
<p class="MsoNormal"><b><span style="font-size:28.0pt;color:#005A9E">Nonlinear optics of graphene and topological insulators<o:p></o:p></span></b></p>
<p class="MsoNormal"><b><span lang="EN" style="font-size:28.0pt;color:#860000">Prof. Alexey Belyanin, Texas A&M University<o:p></o:p></span></b></p>
<p class="MsoNormal"><b><span lang="EN" style="font-size:13.5pt"><br>
</span></b><!--[if gte vml 1]><v:shapetype id="_x0000_t75" coordsize="21600,21600" o:spt="75" o:preferrelative="t" path="m@4@5l@4@11@9@11@9@5xe" filled="f" stroked="f">
<v:stroke joinstyle="miter" />
<v:formulas>
<v:f eqn="if lineDrawn pixelLineWidth 0" />
<v:f eqn="sum @0 1 0" />
<v:f eqn="sum 0 0 @1" />
<v:f eqn="prod @2 1 2" />
<v:f eqn="prod @3 21600 pixelWidth" />
<v:f eqn="prod @3 21600 pixelHeight" />
<v:f eqn="sum @0 0 1" />
<v:f eqn="prod @6 1 2" />
<v:f eqn="prod @7 21600 pixelWidth" />
<v:f eqn="sum @8 21600 0" />
<v:f eqn="prod @7 21600 pixelHeight" />
<v:f eqn="sum @10 21600 0" />
</v:formulas>
<v:path o:extrusionok="f" gradientshapeok="t" o:connecttype="rect" />
<o:lock v:ext="edit" aspectratio="t" />
</v:shapetype><v:shape id="Picture_x0020_1" o:spid="_x0000_s1026" type="#_x0000_t75" alt="r. Alexey Belyanin" style='position:absolute;margin-left:302.25pt;margin-top:15.05pt;width:140.25pt;height:140.25pt;z-index:251658240;visibility:visible;mso-wrap-style:square;mso-width-percent:0;mso-height-percent:0;mso-wrap-distance-left:9pt;mso-wrap-distance-top:0;mso-wrap-distance-right:9pt;mso-wrap-distance-bottom:0;mso-position-horizontal:absolute;mso-position-horizontal-relative:text;mso-position-vertical:absolute;mso-position-vertical-relative:text;mso-width-percent:0;mso-height-percent:0;mso-width-relative:page;mso-height-relative:page'>
<v:imagedata src="cid:image004.jpg@01D00243.CE880730" o:title="r" />
<w:wrap type="square"/>
</v:shape><![endif]--><![if !vml]><img width="187" height="187" src="cid:image002.jpg@01D00244.7BE018A0" align="left" hspace="12" alt="r. Alexey Belyanin" v:shapes="Picture_x0020_1"><![endif]><span lang="EN">Dr.
Alexey Belyanin is Professor of Physics and Astronomy at Texas A&M University. He
</span>received his PhD in Physics in 1995 from the Russian Academy of Sciences, where he did research on high-energy astrophysics, cosmology, and quantum optics.<span lang="EN"> </span>His current research focuses on ultrafast, nonlinear, and quantum optics
of semiconductors, nanostructures, and novel materials. <span lang="EN">He has coauthored over 110 articles in refereed journals and 5 patents. Professor Belyanin has served
</span>as chair of international conferences and received a number of awards for research. His research was featured in news articles in Nature, Science, Nature Photonics, Laser Focus World, Optoelectronics Magazine, and other media.<span lang="EN"> He is a
Fellow of the American Physical Society. More information about Prof. Belyanin and his research can be found at </span><a href="http://people.physics.tamu.edu/belyanin/">http://people.physics.tamu.edu/belyanin/</a>
<o:p></o:p></p>
<p class="MsoNormal"><b><span lang="EN" style="font-size:13.5pt"><o:p> </o:p></span></b></p>
<p class="MsoNormal" style="text-align:justify"><b><i><span lang="EN">Abstract:</span></i></b><br>
Recently there has been a surge of interest in emergent 2D materials with chiral symmetry and gapless linear spectrum of free carriers near the Dirac point where the energy bands form a cone in the momentum space. Most notable examples include graphene and
surface states in topological insulators such as Bi<sub>2</sub>Se<sub>3</sub>. So far the main effort was directed at studying their topological properties and carrier transport. In this talk we show that the systems with massless Dirac electrons possess a
giant mid/far-infrared optical nonlinearity, perhaps the highest among known materials. Giant optical nonlinearity enables generation of coherent mid-infrared and terahertz radiation through resonant difference-frequency generation, four-wave mixing, and Raman
scattering. Another interesting application is the generation of polarization-entangled light. Unique nonlinear properties of Dirac fermions enable schemes with a high signal to noise ratio and high generation rate of entangled photons. They also open an interesting
possibility of detection and control of electron states near the Dirac point by means of nonlinear optics.<span lang="EN"><br>
<b><i>References:</i></b> <br>
</span>[1] X. Yao and A. Belyanin, Phys. Rev. Lett. 108, 255503 (2012).<o:p></o:p></p>
<p class="MsoNormal" style="text-align:justify">[2] M. Tokman, X. Yao and A. Belyanin, Phys. Rev. Lett. 110, 0774904 (2013).<o:p></o:p></p>
<p class="MsoNormal" style="text-align:justify">[3] X. Yao, M. Tokman, and A. Belyanin, Phys. Rev. Lett. 112, 055501 (2014).<o:p></o:p></p>
<p class="MsoNoSpacing"><b><span style="font-size:26.0pt;color:#1F497D"><o:p> </o:p></span></b></p>
</div>
</body>
</html>