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Message ID: 2014     Entry time: Tue Feb 9 00:00:11 2016
Author: KojiN 
Type: Misc 
Category: PD QE 
Subject: Measurement of a beam profile 

For measuring  a current beam profile, the setup as shown in Fig. 1 was prepared.

At first, laser powers at Point 1 and 2 were measured and the results were

* at Point 1: 17.71 mW

* at Point 2: 16.15 mW

The difference may be come from the loss of HWP #2 and the beam damped by Iris.

(Laser power just in front of the Iris cannot be measured because of the space constraint.)

Then the beam profile was measured as shown in Fig. 2.

The measurement was perfomed from 0 cm to 25.4 cm (11 points) and in the measurement the angles of HWP #1 and #2 were 48.1 degree and 22.4 degree, repsectively.

(The zero point is set after the PBS as shown in Fig. 1.)

As shown in Fig. 2, the beam profile, in especially y-direction, seems to be a bit strange.

This is condiered to be an effect of a kind of saturation, but this is a just guess.

The measured data and the fitted curves are shown in Fig. 3. 

Fig. 1 Current setup.
Fig. 2 Beam profile measurement.
Fig. 3. Measured data and fitted curves.

 

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BeamAfterPBS.pdf
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