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Message ID: 2023     Entry time: Fri Feb 19 00:39:24 2016
Author: KojiN 
Type: Misc 
Category: PD QE 
Subject: First QE measurement with the reflector 

QEs (with the glass window) with the reflector were measured as shown in Fig. 1.

The radius of curvature of the reflector is 25 cm and the reflector was placed at a distance of 5 cm from the PD.

At the reflector position, the beam size is 403 um in x-direction and 391 um in y-direction.

And, at the PD position, the beam size of the light reflected by the reflector is 435 um in x-direction and 422 um in y-direction.

When Fig. 1 is observed, the QEs in S-pol are less enhanced than that in P-pol.

This is because there are a few lights which are reflected by the PD and have almost the same power, in other words in this measurement only one or two beams are re-input to the PD by reflector.

In fact, we can see the two peak output voltages of the PD when the reflector are rotated in the yaw direction.

Fig. 1 Measured enhenced and not enhanced QEs.

QE_enh.txt

Attachment 1: QE_enh.txt  345 Bytes  | Hide | Hide all
# angle(deg) enh.vol(V,P) error vol(V,P) error enh.vol(V.S) error vol(V,S) error
-15. 2.12    0.01    1.94    0.01    2.12    0.01    1.94    0.01
-30. 2.12    0.01    2.00    0.01    2.08    0.01    1.88    0.01
-45. 2.12    0.01    2.08    0.01    1.92    0.01    1.76    0.01
-60. 2.10    0.01    2.04    0.01    1.62    0.01    1.46    0.02
Attachment 2: QE_enh.pdf  6 kB  | Hide | Hide all
QE_enh.pdf
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