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Entry  Wed Jul 24 18:13:05 2013, Chloe, Notes, ECDL, Current Driver 
    Reply  Thu Jul 25 18:13:11 2013, Chloe, Notes, ECDL, Current Driver/TEC thermistor_temperature-resistance.xlsx
       Reply  Fri Jul 26 17:51:02 2013, Chloe, Notes, ECDL, Current Driver/TEC 
          Reply  Mon Jul 29 19:06:31 2013, Chloe, Notes, ECDL, Current Driver/TEC 
             Reply  Tue Jul 30 17:55:21 2013, Chloe, Notes, ECDL, Current Driver/TEC working!.jpg
Message ID: 1268     Entry time: Tue Jul 30 17:55:21 2013     In reply to: 1262
Author: Chloe 
Type: Notes 
Category: ECDL 
Subject: Current Driver/TEC 

I fixed the solder joints on the TEC by using heat shrink to make sure nothing short circuits. I figured it would be cautious to go ahead and do to avoid future problems. 

Tara worked with me for a bit trying to improve our temporary setup. We trimmed the legs on the laser diode so it will fit snugly into the socket. Then, we used a mirror mount adapter to fix the laser diode securely so there is less movement from this part. 

We found a collimator and used it in combination with another lens (planar/convex). We were able to line this up so that the beam spot is comparable to a handheld laser output, but this has a large cavity. Instead, we need to find (or order?) a very short focal length lens (something on the order of several mm). This is because the beam diverges way too fast to use any of the lenses we have been trying in the lab. From Thorlabs and Newport, it seems like it's difficult to find lenses with focal length <10mm. 

I also used a visible handheld laser pointer to determine the orientation of the blazing on the grating. There is an arrow marked, which is standard and points in the direction from the normal of the grating surface to the next trough in the blazing. This means that there are 2 possible orientations the grating will operate at - it is better to have the blazing point away from the laser diode. See: http://gratings.newport.com/library/technotes/technote7.asp This is good to know so that we won't have to reattach the grating to the diode mount if we do it wrong the first time. 

The machined parts should be done tomorrow so we can begin some construction. Today's setup is pictured, with the output beam on the IR card. 

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