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<ol class="chapter"><li><a href="../polsim.html"><strong aria-hidden="true">1.</strong> polsim</a></li><li><a href="../installation.html"><strong aria-hidden="true">2.</strong> Installation</a></li><li><a href="../usage.html"><strong aria-hidden="true">3.</strong> Usage</a></li><li><a href="../simulations.html"><strong aria-hidden="true">4.</strong> Simulations</a></li><li><ol class="section"><li><a href="../format.html"><strong aria-hidden="true">4.1.</strong> File Format</a></li><li><a href="../beams.html"><strong aria-hidden="true">4.2.</strong> Beams</a></li><li><ol class="section"><li><a href="../beams/linear.html"><strong aria-hidden="true">4.2.1.</strong> Linearly Polarized</a></li><li><a href="../beams/circular.html"><strong aria-hidden="true">4.2.2.</strong> Circularly Polarized</a></li><li><a href="../beams/elliptical.html"><strong aria-hidden="true">4.2.3.</strong> Elliptically Polarized</a></li></ol></li><li><a href="../elements.html"><strong aria-hidden="true">4.3.</strong> Elements</a></li><li><ol class="section"><li><a href="../elements/polarizer.html"><strong aria-hidden="true">4.3.1.</strong> Polarizer</a></li><li><a href="../elements/rotator.html"><strong aria-hidden="true">4.3.2.</strong> Rotator</a></li><li><a href="../elements/retarder.html"><strong aria-hidden="true">4.3.3.</strong> Retarder</a></li><li><a href="../elements/qwp.html"><strong aria-hidden="true">4.3.4.</strong> Quarter-Wave Plate</a></li><li><a href="../elements/hwp.html"><strong aria-hidden="true">4.3.5.</strong> Half-Wave Plate</a></li></ol></li></ol></li><li><a href="../examples.html"><strong aria-hidden="true">5.</strong> Examples</a></li><li><ol class="section"><li><a href="../examples/one_polarizer.html"><strong aria-hidden="true">5.1.</strong> One Polarizer</a></li><li><a href="../examples/crossed_polarizers.html"><strong aria-hidden="true">5.2.</strong> Crossed Polarizers</a></li><li><a href="../examples/circular_polarizer.html" class="active"><strong aria-hidden="true">5.3.</strong> Circular Polarizer</a></li></ol></li><li><a href="../reference.html"><strong aria-hidden="true">6.</strong> Quick Reference</a></li><li><a href="../conventions.html"><strong aria-hidden="true">7.</strong> Conventions</a></li></ol>
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<h1 class="menu-title">polsim Documentation</h1>
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<main>
<a class="header" href="#circular-polarizer" id="circular-polarizer"><h1>Circular Polarizer</h1></a>
<p>If you have a linearly polarized beam you can convert it into a circularly polarized beam with a polarizer and a QWP. Here's what that looks like:</p>
<pre><code class="language-toml">[beam]
polarization = "linear"
angle = 90
angle_units = "degrees"
[[elements]]
element_type = "polarizer"
angle = 45
angle_units = "degrees"
[[elements]]
element_type = "qwp"
angle = 0
angle_units = "degrees"
</code></pre>
<p>The key here is that the QWP and the polarizer need to be at 45 degrees relative to on another. If this angle is off, you'll end up with elliptical polarization. Here's what the output looks like:</p>
<pre><code>$ polsim circular_polarizer.toml
intensity: 5.00000e-1
x_mag: 5.00000e-1
x_phase: 0.00000e0
y_mag: 5.00000e-1
y_phase: 1.57080e0
</code></pre>
<p>If you go back through the previous two examples, you'll see that the phases (<code>x_phase</code> and <code>y_phase</code>) are zero for both examples. This time, however, <code>y_phase</code> is not zero, it's <code>pi/2</code>! That tells us that there is a delay between the x- and y-components.</p>
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