Page 2 of 2 FirstFirst 12
Results 11 to 13 of 13

Thread: Tiny 2.4mm diameter lens with 1.45mm FL, what application might a lens so small have?

  1. #11
    Join Date
    Aug 2014
    Location
    Doha, Qatar
    Posts
    379

    Default

    I have the mirrors to do that just found it more difficult perhaps i should reconsider. Thanks for your help again.

  2. #12
    Join Date
    Apr 2011
    Location
    CT
    Posts
    34

    Default

    Hey Guys,

    I've done some quick beam size measurements with this lens.

    As a quick note first i took the lens out of its Copper mount Which i dont recommend anyone try unless you are OK with the possible chance of breaking the lens while doing it because its really glued in there with 2 little tiny drops of this really strong adhisive. Anyway i got it out and mounted it in a little aluminum lenses holder that i made to hold the lens that slides into a standard 6.35mm lens barrel. You would be better off getting the lens from Thorlabs already unmounted if you plan to not use it with the copper mount:



    This lenses focus Just fine for every diode i have tried it on and that includes both normal can and long can red diodes in 3.8mm or 5.6mm and ill just say make sure your diode protrudes some when your looking inside your module through the lens threaded side as i do have one module that the diode can sits flush and it doesn't focus but that was a custom module i made myself and most of the module people make have the diodes protruding out some but its just a thought to remember.. Just tried it on a Blue 9mm Can Package and its a No go. Wont focus. But on the Array 3.5W De-canned 9mm blue diodes it works just fine. So if one want to buy the A-Coated ones that are coated for Blue/Green just note that it wont work on 9mm canned diodes unless you decap them.

    Info:
    -P73 diode running at 700mA with Output power 580mW

    -A Density filter to drop the intensity of the beam and block most of the unwanted scatter.

    Quick setup as i was in the middle of another project so its a little messy:

    At the Aperture "~15mm from the Lens" Beam size measured 1.8mm x .65mm




    At 8 meters beam size measured 190.50mm (7.5") x 3.7mm



    Andy was right this lens and mount was original designed to go in a single mode lab laser module. Something along the lines like a Coherent Cube. Diode lab lasers typically usually only need a very thin tight beam for at least a few feet because what they are being used for only matters in that short distance so depending on the application the shorter the FL the better.. Most diode lab laser that i know of and own are like this. Although this lens with copper mount was designed to go in a Single mode lab laser that doesn't mean you can only use it for Single mode diodes. This lens and or lens mount setup will work just fine for Multi-mode diodes of course. I was just referring to the entire mount lens setup and what its initial use was for. Talking about just the lens for a second, a lens is a Lens and can be used for whatever SM/MM diode you choose as long as the application calls for such lens. Thats the way i see it.

    The Application i see this kind of lens being used for most is anywhere from beam collimation,fiber coupling and pumping of a Crystal.

    I just got in some even shorter FL lens with .70mm FL 3mm dia and id say these would be used also for the same thing but more so Fiber coupling.

    IMO what it really boils down to is what your application is. If the lens works for your needs then use it. Doesn't matter what they where intended for. But thats just my thought on it.

    The lens was designed to be in a HL63133DG 638nm 170mW lab laser diode module. Not sure which head it actual is because the head that i did get with all the lenses i bought was not complete and only the diode, lens and a couple prisms where on the laser block. So id say the coating is more specified closer to the 640nm range rather then the IR.

    As a side note though For Type B "Red coated lenses" typically the darker the blue tint coating is the more its for the visible red range IE ~600nm-690nm. The "Lighter blue" coatings are usually more specified for the IR "Red" range. IE 700nm-1050nm. Although both dark and Light blue Type B coated lenses will work just fine for the typical 600nm-1050nm I just noticed that the Darker Blue coated lenses are usually for the Visible end of the Red.

    Eric, If you want ill send you a lens in the copper mount if you like to do some testing on it if that would help everyone out. I don't have alot of C-lens here to try out right now otherwise i would do it. I only have a set of Lava Ones left that are loose and iam weeks away from placing another order for some more Edmund ones. Iam not sure if those would be a good example to use now adays.(have not really keeped up with what everyone is using now as iam still using the Edmunds and the ones Dave sells)

    I have used these 1.45mm FL lenses sometime ago during testing when we where all searching to find the best lens to use form the G71/P73 but i cant remember my numbers from then. But if i recall results where comparable to the 2mm lens we are all use to using now i just cant remember if i tested this 1.45mm FL lens fully to get an answer if it was better or worse. I think what happend was everyone settled for the 2mm FL lens and so did i and i dint finish my testing at that time...something along those lines.

    I could have sworn though that you tested this lens? I thought i read somewhere "Along time ago i think" you mentioned 1.45mm FL before. Maybe in the big P73 thread but i could have sworn you tried this lens before or something similar?

    Anyway id say if you would rather not have it in the mount as iam guessing you would rather mount it in a lens barrel your better off getting it straight from Thorlabs unmounted double the price then the ones in the listed in the copper mount its still a good deal IMO.
    https://www.thorlabs.com/thorproduct...umber=354140-B

    Let me know and ill send you one if you like.
    Last edited by Lazeerer; 05-25-2015 at 02:23.

  3. #13
    Join Date
    Feb 2011
    Location
    New Hampshire
    Posts
    3,513

    Default

    Lazeerer,

    I may have tested this lens back when. I may even have one in my drawer of odd bits. I'm not that interested in testing this lens because I agree with you that this lens will not result in a better path to moderate beam diameter/ low divergence projection than the existing 2mm lens I get from Dave or the 4mm lens that I get from Optima. A lens is a lens. The very short FL will make precise, aberration-free alignment difficult, but for short throw applications it has its role.

Posting Permissions

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