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KAGRA MIR (Polarization)
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MarcEisenmann - 23:10, Tuesday 09 November 2021 (2731)Get code to link to this report
TAMA 1 (Shinkosha) birefringence measurement

This entry reports the birefringence measurement of TAMA #1 with 1.5cm radius, 0.25 mm step size, 0.5s wait time and 0.488mW input power.

Due to time constraints only 3 measurements were possible.

Note that the AC and DC was realigned before input polarization calibration and with sample and that here 0 deg polarization angle corresponds to s polarization.

The analysis code was checked using the Shinkosha7 data and produced identical results.

The main result is that polarization, theta and delta_n are quite uniform but the main variation corresponds also to the maximum absorption (see entries 2723 or 2672) while the triangular patterns does not seem to affect significantly these parameters.

Images attached to this report
2731_20211109150808_xsi0deg.png 2731_20211109150815_xsi30deg.png 2731_20211109150823_xsi60deg.png 2731_20211109150831_s0.png 2731_20211109150845_s1.png 2731_20211109150852_meandntheta.png 2731_20211109150858_deltan.png 2731_20211109150906_theta.png
Comments related to this report
SimonZeidler - 16:57, Wednesday 10 November 2021 (2733)

That looks very good, indeed!
What you can do in addition is to check for the second (negative) solution according to theory, as I reported last meeting.

An important point is also to be very precise with all input parameters. For example, it isn't enough to set the thickness to just 6cm or so but to take into account the refraction due to the inclination and the hence extended beam path.