Wuben        
Results 1 to 10 of 10

Thread: Laser and low temperature

  1. #1
    Flashaholic*
    Join Date
    Oct 2002
    Location
    Baden.at
    Posts
    4,488

    Default Laser and low temperature

    Finally temps here start to get into autumn/winter state.
    My cheap greenie pointer, while working acceptable inside or till now (warm temps),
    barely shows a dot at 15 deg. Celsius or below.
    It needs to be warmed up inside the hands quite some time.

    Unfortunately I planned to use it as a signaling device for hiking, having it not work 1/2 of the year makes a really unreliable tool.

    Anyone with a better model from one of the respected sellers in here, does this also happen to Your models?

    I m planning to get a better, maybe more powerful one in the 15 mW class.
    Same question for this --> working in the cold?

  2. #2

    Default Re: Laser and low temperature

    DPSS lasers are very temperature dependant. Without even considering the crystals, temperature will effect the pump diode itself. Too hot and the diode will red shift slithly beyond 808nm, to cold and it will blue shift towards 807nm. This slight variation in frequency will reduce the output of the laser as optimal lasing of the crystal occurs with 808nm. Temperature will also effect the crystal set as well, so add that to the mix and you can see it's not going to be easy to have a stable laser in cold climates. Now having said that, every laser is unique, so some will react differently then others. For example I have a laser that actually runs better when hot then at room temperature. Likewise I also have one or two that prefer the cold over room temperature.

    I've tested many many types of lasers (large, small, portable etc.), though since you are looking for a 15mW, there's only a few that you can choose from. The new Wicked model, CNI model or perhaps a modded leadlight. Any one of those will probably be fine, though having tested them I have found th new Wicked models to be much more stable then their previous CNI models. On the other hand a modded leadlight will probably be cheaper, so I guess it depends on your budget.

    Also I should point out that Atlasnova seems to have good deals on lasers in that output range.
    Last edited by Athoul; 11-09-2006 at 05:34 AM.
    cheers,
    Sean.

  3. #3
    Flashaholic
    Join Date
    Mar 2004
    Location
    Spokane, WA
    Posts
    202

    Popcorn Re: Laser and low temperature

    Quote Originally Posted by yellow
    Finally temps here start to get into autumn/winter state.
    My cheap greenie pointer, while working acceptable inside or till now (warm temps),
    barely shows a dot at 15 deg. Celsius or below.
    It needs to be warmed up inside the hands quite some time.

    Unfortunately I planned to use it as a signaling device for hiking, having it not work 1/2 of the year makes a really unreliable tool.

    Anyone with a better model from one of the respected sellers in here, does this also happen to Your models?

    I m planning to get a better, maybe more powerful one in the 15 mW class.
    Same question for this --> working in the cold?
    It is probable that your laser has the current to the diode set at its maximum or more. The MCA's on the cheapies are also very small. I cannot think of any complaints about low-temperature operation for my atlasnova's. Here is an interesting link that illustrates this:

    http://www.candlepowerforums.com/vb/...d.php?t=117349
    Best Regards,
    Arnold Beland
    Pleas Do Not post Spam

  4. #4
    Flashaholic
    Join Date
    Nov 2005
    Location
    fairbanks,North pole Alaska
    Posts
    236

    Default Re: Laser and low temperature

    well last winter and this winter ive used my lasers out side with out too much problems. with temps in the -50F range they of course got sapped pretty fast but -30F and colder they did surpringly well.


    its been in the -5F to -20Fs temps day and night all week so far and ive been playing with both my atlasnova 43mw and modded 105 from vital sprits outside with bearly any probelms with their power output

    energizer e2 lithium work great in the cold




    so basiclly from my expereince above -20F with good batteries your good to go

    im not sure how cold that is in Celsius?
    Last edited by alaskawolf; 11-09-2006 at 03:37 PM.

  5. #5
    Flashaholic*
    Join Date
    Oct 2002
    Location
    Baden.at
    Posts
    4,488

    Default

    found a link to a converter (down at the side)
    http://www.chemie.fu-berlin.de/chemi...nits.html#temp

    info:...............Celsius..Fahrenheit
    boiling water:.....100........212
    human body:.......37..........98
    Ice:....................0..........32

    So Your -20 is WAY much less than we have here in hardest winter.
    (laser not working temp was about 60 F)
    Last edited by yellow; 11-09-2006 at 03:51 PM.

  6. #6
    Flashaholic
    Join Date
    Nov 2005
    Location
    fairbanks,North pole Alaska
    Posts
    236

    Default Re: Laser and low temperature

    if your laser isnt working at just 60F i seriously think you might have a defective laser. it hasnt been in the 60s here in months


    time for a green laser pointer upgrade for you

  7. #7

    Default Re: Laser and low temperature

    The problem with greenies in the cold is the KTP crystal. This is what converts the infrared (1064nm) to green (532 nm). In cold weather the efficiency of this xtal goes way down. So less green until it warms up (works best at temp > 70F).

    Usually the pump diode will not be affected by cold - unless it's really cold (< -20C) - then it's wavelength may shift to the point where it no longer couples well with the xtal.

    For higher power greens (> 20 mW ??) used in the cold they tend to warm up quickly enough. For a lower power greenie your best option is to keep the pointer in a pocket close to your body so it stays warm until you need to use it.

  8. #8
    Flashaholic
    Join Date
    Aug 2006
    Location
    Vancouver , Washington USA
    Posts
    102

    Default Re: Laser and low temperature

    Quote Originally Posted by yellow
    found a link to a converter (down at the side)
    http://www.chemie.fu-berlin.de/chemi...nits.html#temp

    info:...............Celsius..Fahrenheit
    boiling water:.....100........212
    human body:.......37..........98
    Ice:....................0..........32

    So Your -20 is WAY much less than we have here in hardest winter.
    (laser not working temp was about 60 F)
    errrr.....actually -40F is equal to -40 celsius -20c is i remember right is about -4F The curve is not equal starting at 0 celsius both directions
    Last edited by livetofall; 11-12-2006 at 03:39 AM.

  9. #9
    Flashaholic*
    Join Date
    Oct 2002
    Location
    Baden.at
    Posts
    4,488

    Default

    * based on inserting Your -40 F into the converter in the link, You are right, thats -40 C.
    * alaskawolfs -20 F inserted is -29 C, so MUCH less (read: colder) than here in winter
    * -20 C is -4 F, You are right again

    I mean: what are You and Your smiley referring to?
    :Thinking:
    Last edited by yellow; 11-12-2006 at 09:17 AM. Reason: less = colder

  10. #10
    Flashaholic
    Join Date
    Nov 2005
    Location
    fairbanks,North pole Alaska
    Posts
    236

    Default Re: Laser and low temperature

    Quote Originally Posted by FloggedSynapse

    For higher power greens (> 20 mW ??) used in the cold they tend to warm up quickly enough. For a lower power greenie your best option is to keep the pointer in a pocket close to your body so it stays warm until you need to use it.
    i want to make a warm fur coat for mine

    -26F right now

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •