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Entry  Tue Aug 17 16:31:55 2010, Aidan, Things to Buy, Laser, Bought a laser diode from Thorlabs for HWS 
    Reply  Mon Aug 23 08:43:16 2010, Aidan, Things to Buy, Laser, Bought a laser diode from Thorlabs for HWS 
Message ID: 93     Entry time: Mon Aug 23 08:43:16 2010     In reply to: 90
Author: Aidan 
Type: Things to Buy 
Category: Laser 
Subject: Bought a laser diode from Thorlabs for HWS 

It arrived on Friday.

Quote:

http://www.thorlabs.com/thorProduct.cfm?partNumber=CPS180

I bought this laser diode from Thorlabs today to try the current modulation trick Phil and I discussed last Friday. 

That is:

  1. Accept that there will be interference fringes on the Hartmann sensor probe beam with a laser diode source (especially if the probe beam is the retro-reflection from a Michelson interferometer with a macroscopic arm length difference)
  2. Modulate the current of the laser diode source to vary its wavelength by a few hundreds on nm. Do this on a time scale that is much faster than the exposure time for a Hartmann sensor measurement
  3. The contrast of the interference fringes should average out and the exposure should appear to be the sum of two incoherent beams.

 

 

 

 

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