1. Forum
  2. Usenet
  3. SCI.ELECTRONICS.COMPONENT

  • Long shot: operating high power laser modules in vacuum

    From [email protected]@21:1/5 to All on Thu Mar 28 16:06:09 2019
    Dudes of all flavours;

    I have an itch: I wish to run a 10W laser module in a vacuum chamber (UHV: 10^-6mbar or so).

    Anyone got any direct experience of the 'fun' in keeping the diode cool?
    And any tips on doing so?
    <heat pipes, lots of copper, lowered duty cycles etc.>

    Cheers;

    -James G.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From James Garry@21:1/5 to All on Fri Mar 29 11:56:18 2019
    Jon,

    Aye, I've cooled lamps (tiddly 10Watt deuterium lamps, of all things) inside vacuum chambers with fluid lines on KF flanges in the past.

    But the suggestion of mating that to the chamber wall's a good one - I suspect I'll have to remake the mount that the laser diode sits in.

    <mind, I've yet to acquire the laser module so I suspect that there'll be some entertainment ahead to remove the diode, fabricate a new mount, and reassemble>

    Thanks!

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Jon Elson@21:1/5 to jrcgarry on Fri Mar 29 13:36:18 2019
    On Thu, 28 Mar 2019 16:06:09 -0700, jrcgarry wrote:

    Dudes of all flavours;

    I have an itch: I wish to run a 10W laser module in a vacuum chamber
    (UHV: 10^-6mbar or so).

    Anyone got any direct experience of the 'fun' in keeping the diode cool?
    And any tips on doing so?
    <heat pipes, lots of copper, lowered duty cycles etc.>
    Water cooling loops will work, but that is pretty complicated. In
    vacuum, metal surfaces that are pressed together conduct heat very poorly.
    You need some sort of thermal conductor (either loaded silicone grease or gap-pads) to carry the heat across. If your laser can be attached to the chamber by some structure, that can conduct the heat out.

    Jon

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From James Garry@21:1/5 to All on Fri Mar 29 17:02:34 2019
    Thanks Phil.

    A solid recommendation - Indium foil is known to me - as is Grafoil.

    Still prevaricating over the laser module choice.

    Cheers.

    -JG

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Phil Hobbs@21:1/5 to Jon Elson on Fri Mar 29 19:40:57 2019
    On 3/29/19 2:36 PM, Jon Elson wrote:
    On Thu, 28 Mar 2019 16:06:09 -0700, jrcgarry wrote:

    Dudes of all flavours;

    I have an itch: I wish to run a 10W laser module in a vacuum chamber
    (UHV: 10^-6mbar or so).

    Anyone got any direct experience of the 'fun' in keeping the diode cool?
    And any tips on doing so?
    <heat pipes, lots of copper, lowered duty cycles etc.>
    Water cooling loops will work, but that is pretty complicated. In
    vacuum, metal surfaces that are pressed together conduct heat very poorly. You need some sort of thermal conductor (either loaded silicone grease or gap-pads) to carry the heat across. If your laser can be attached to the chamber by some structure, that can conduct the heat out.

    Jon


    Heat sinking to the wall is the way to go, for sure. However, grease
    and polymers are verboten in UHV on account of outgassing. You can't
    even use soft solder because it outgasses during bakeout.

    I'd recommend using indium foil as a thermal interface between the
    module and the chamber wall. If you compress it enough, it'll seal in
    the incidental gas it accumulates at ambient pressure pretty reliably. Otherwise it'll probably outgas like a screw with no vent hole.

    Cheers

    Phil Hobbs

    --
    Dr Philip C D Hobbs
    Principal Consultant
    ElectroOptical Innovations LLC / Hobbs ElectroOptics
    Optics, Electro-optics, Photonics, Analog Electronics
    Briarcliff Manor NY 10510

    http://electrooptical.net
    http://hobbs-eo.com

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)