<div dir="ltr">Thank you very much</div><br><div class="gmail_quote"><div dir="ltr">Le mer. 5 déc. 2018 à 06:36, Gavin Abo <<a href="mailto:gsabo@crimson.ua.edu">gsabo@crimson.ua.edu</a>> a écrit :<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
  
    
  
  <div text="#000000" bgcolor="#FFFFFF">
    <p>I believe:</p>
    <p>delta_n=n_zz-n_xx</p>
    <p>However, you may check it for yourself:</p>
    <p>Birefringence := delta_n=n_e-n_o [1,2]</p>
    <p>Orthorhombic ɛ_xx and <span class="m_-7919827869244143092st">ɛ_yy perpendicular and </span><span class="m_-7919827869244143092st"><span class="m_-7919827869244143092st">ɛ_zz parallel [3] a bit similar to
          tetragonal that has </span></span><span class="m_-7919827869244143092st"><span class="m_-7919827869244143092st">ɛ_xx = <span class="m_-7919827869244143092st">ɛ_yy and </span></span></span><span class="m_-7919827869244143092st"><span class="m_-7919827869244143092st"><span class="m_-7919827869244143092st"><span class="m_-7919827869244143092st"><span class="m_-7919827869244143092st">ɛ_zz tensor (Table 1.1) [4]<br>
              </span></span></span></span></span></p>
    <p>n_x = sqrt(ɛ_xx/ɛ_o) and n_z = sqrt(ɛ_zz/ɛ_o) [5,6]</p>
    <p>Section 1.4 of [4]:</p>
    <p>n_e = n_z (or n_zz) and n_o = n_x (or n_xx)<br>
    </p>
    [1] <a class="m_-7919827869244143092moz-txt-link-freetext" href="https://en.wikipedia.org/wiki/Birefringence#Uniaxial_materials" target="_blank">https://en.wikipedia.org/wiki/Birefringence#Uniaxial_materials</a><br>
    [2]
<a class="m_-7919827869244143092moz-txt-link-freetext" href="http://shodhganga.inflibnet.ac.in/bitstream/10603/4722/13/13_chapter%203.pdf" target="_blank">http://shodhganga.inflibnet.ac.in/bitstream/10603/4722/13/13_chapter%203.pdf</a>
    (Equation 3.24)<br>
    [3] <a class="m_-7919827869244143092moz-txt-link-freetext" href="https://pubs.acs.org/doi/abs/10.1021/jp410786w" target="_blank">https://pubs.acs.org/doi/abs/10.1021/jp410786w</a><br>
    [4]
<a class="m_-7919827869244143092moz-txt-link-freetext" href="http://www.physics.ucc.ie/fpetersweb/FrankWeb/courses/PY4118/Notes/Symmetry%20of%20Tensor%202.pdf" target="_blank">http://www.physics.ucc.ie/fpetersweb/FrankWeb/courses/PY4118/Notes/Symmetry%20of%20Tensor%202.pdf</a><br>
    [5] <a class="m_-7919827869244143092moz-txt-link-freetext" href="https://www.as-photonics.com/book_page/book-preview.pdf" target="_blank">https://www.as-photonics.com/book_page/book-preview.pdf</a>
    (Equations 2.13 and 2.15)<br>
    [6]
<a class="m_-7919827869244143092moz-txt-link-freetext" href="https://nanoed.tul.cz/pluginfile.php/1598/mod_resource/content/1/Optick%C3%A9%20vlastnosti%20krystal%C5%AF.pdf" target="_blank">https://nanoed.tul.cz/pluginfile.php/1598/mod_resource/content/1/Optick%C3%A9%20vlastnosti%20krystal%C5%AF.pdf</a>
    (slide 5)
    <p><br>
    </p>
    <div class="m_-7919827869244143092moz-cite-prefix">On 12/4/2018 5:54 PM, Wien2k User
      wrote:<br>
    </div>
    <blockquote type="cite">
      
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        <div dir="ltr">
          <div dir="ltr">
            <div dir="ltr">Dear Wien2k users;<br>
              <br>
              <span class="m_-7919827869244143092gmail-tlid-translation m_-7919827869244143092gmail-translation"><span title="" class="m_-7919827869244143092gmail-">for a tetragonal material, the
                  birefringence is given by :<br>
                </span></span></div>
            <div><span class="m_-7919827869244143092gmail-tlid-translation m_-7919827869244143092gmail-translation"><span title="" class="m_-7919827869244143092gmail-">delta_n=n_xx-n_zz <br>
                  or </span></span><br>
              <span class="m_-7919827869244143092gmail-tlid-translation m_-7919827869244143092gmail-translation"><span title="" class="m_-7919827869244143092gmail-"><span class="m_-7919827869244143092gmail-tlid-translation m_-7919827869244143092gmail-translation"><span title="" class="m_-7919827869244143092gmail-"><span class="m_-7919827869244143092gmail-tlid-translation m_-7919827869244143092gmail-translation"><span title="" class="m_-7919827869244143092gmail-">delta_n=</span></span>n_zz-n_xx<br>
                    </span></span></span></span></div>
          </div>
        </div>
      </div>
    </blockquote>
    <blockquote type="cite"></blockquote>
  </div>

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