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Entry  Wed Jul 10 17:54:58 2013, Chloe, DailyProgress, ECDL, Solidworks Design base.SLDPRTdiode_mount.SLDPRTgrating_mount.SLDPRTlid.SLDPRTsketch_with_lid.PNG
    Reply  Thu Jul 11 17:51:12 2013, Chloe, DailyProgress, ECDL, Solidworks Design lid.PNGsketch_without_lid.PNG
       Reply  Fri Jul 12 15:25:56 2013, Chloe, DailyProgress, ECDL, Solidworks Design 
          Reply  Thu Jul 18 16:34:22 2013, Chloe, DailyProgress, ECDL, Solidworks Design 
             Reply  Mon Jul 22 18:30:20 2013, Chloe, DailyProgress, ECDL, Solidworks Design final_3d.PNGfinal_top.PNG
                Reply  Tue Jul 23 17:59:47 2013, Chloe, DailyProgress, ECDL, Solidworks Design 
Message ID: 1238     Entry time: Fri Jul 12 15:25:56 2013     In reply to: 1236     Reply to this: 1244
Author: Chloe 
Type: DailyProgress 
Category: ECDL 
Subject: Solidworks Design 




 Grating mount: I examined different ways to attach the grating to the grating mount. Our options are epoxy or some sort of actual mount the grating fits into. I finally decided that we should use epoxy for the following reasons:

  • Epoxy is much easier to align and attach than a mount would be, since a mount would rely on being machined extremely precisely
  • Epoxy has a much lower coefficient of thermal expansion (about 60 ppm/K) by about a factor of 4 than aluminum or any metal we would use to build the mount (about 230 ppm/K). This means that epoxy will be less affected by temperature, so it will affect our cavity length a lot less. 
  • It is impossible to design a stable mount that adjusts to clamp in the grating, while still being fixed solidly to the grating mount. I spent a long time brainstorming different designs, and looking at mounts from Thorlabs and Newport for ideas. Any mount that would clamp the grating in well would require some adjustability for small variations in the grating size, and as a result, cannot be fixed onto the grating mount without an excessive number of parts. 


Change of PZT: Our PZT choice relies on how much the PZT will need to be able to move. This changes the length of the cavity as well as the angle of the diffraction grating, and the screw on the PZT will be used to tune the angle. I calculated we will have a 400 nm change in wavelength per mm of the screw length changed, meaning we will only be making changes of less than a mm in the screw length. It made the choice of PZT from before seem a bit excessive. 

Instead, I was thinking of having a very short micrometer screw (http://eksmaoptics.com/opto-mechanical-components/adjustment-screws-870/micrometer-screws-870-0040/) with a chip piezoactuator (http://www.physikinstrumente.com/en/products/prdetail.php?sortnr=100800). I'm not sure how to build the threading into Solidworks or if this will be possible to mount, though. Need to keep looking into this... 

Shortening collimator tube: I have been corresponding with Thorlabs today about their collimator tube. It is made out of aluminum, and therefore we can probably saw off half of it and leave part of it threaded to mount in the collimator mount. Thorlabs also offers custom modifications, but this will likely take awhile and cost a lot more money. 


All of the changes I discuss above were implemented into the Solidworks figures. I just need to figure out the PZT and the parts should all be ready to be machined. I will also try to update the Wiki page this weekend since I haven't for a long time... 


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