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   Message 141,659 of 143,102   
   Phil Hobbs to Cursitor Doom   
   Re: Driving Lasers   
   13 Dec 25 14:10:55   
   
   From: pcdhSpamMeSenseless@electrooptical.net   
      
   Cursitor Doom  wrote:   
   > On Sat, 13 Dec 2025 11:09:08 -0000 (UTC), Phil Hobbs   
   >  wrote:   
   >   
   >> Gerhard Hoffmann  wrote:   
   >>> Am 13.12.25 um 05:47 schrieb Bill Sloman:   
   >>>   
   >>>> One thing to keep in mid with your constant current source is that the   
   >>>> lasing region is very compact, and even a very brief over-current can   
   >>>> burn it out.   
   >>>>   
   >>>   
   >>> Yes, it is usually the frequency-selective optical reflector grid   
   >>> that dies in ms. Faster than we are used from semiconductors.   
   >>>   
   >>> Gerhard   
   >>>   
   >>>   
   >>   
   >> A nice juicy carpet shock can blow the front facet off much faster than   
   >> that (although the fragments will still be moving for awhile afterwards.   
   >>   
   >> Cheers   
   >>   
   >> Phil Hobbs   
   >   
   > No one seems to have come up with a viable solution, so I've been   
   > giving it some extra thought. I considered the use of a semi-silvered   
   > mirror at 45 degrees to the plane of the beam and sampling the light   
   > level off that reflection, but then realized the loss through the   
   > mirror would be unacceptable. The only other idea I can think of is to   
   > use a mirror just off the plane of the beam which can swivel around   
   > for a split second every few seconds to deflect the beam into the path   
   > of the diode. That seems cumbersome and clunky but it's the only thing   
   > I can come up with, not being a designer of any description.   
   >   
      
   You’re very likely to blow up more lasers trying to do constant power.   
   Start with constant current, then wrap a constant power loop around it.   
      
   Cheers   
      
   Phil Hobbs   
      
   --   
   Dr Philip C D Hobbs  Principal Consultant  ElectroOptical Innovations LLC /   
   Hobbs ElectroOptics  Optics, Electro-optics, Photonics, Analog Electronics   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)   

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