Results 1 to 10 of 10

Thread: Intel Fair Project

  1. #1
    Join Date
    Jan 2007
    Location
    Cupertino, California
    Posts
    2,130

    Default Intel Fair Project

    As some of you may know, I am a high school student. Next year I am planning on entering the Intel Science Fair. I was thinking of making a LED pumped Dye laser. My problem is not the construction, I have a full CNC shop at my disposal and basically unlimited funds, I am wondering if I can actually get to the threshold needed. While I cannot tell you exactly what LEDs I will be using, I can tell you that it will be about 220W of optical light at the required pump wavelength. That is not the input power, but rather the optical power out of the LEDs. I was planning on having a flowing system for the dye in addition to water cooling the dye and LEDs.

    What's your input on this? Can it get to the threshold for lasing with that?
    CLICKY!!!

    Admin: In the immortal words of Captain Planet: YOU HAVE THE POWER
    Admin: (To quit being a bitch)

  2. #2
    Join Date
    Jan 2007
    Location
    Sheepsville, Wales, UK
    Posts
    3,372

    Default

    Hey ben
    I cant offer any advice but that sounds like a cool project - make sure you show us your results - and I know you cant say which LEDs you intend to use but I think we can guess where the source is - did your dad just shout you for dinner then

    Rob
    If you need to ask the question 'whats so good about a laser' - you won't understand the answer.
    -----------------------------------------------------------------------------------------------
    Laserists do it by the nanometre.

    Stanwax Laser is a Corporate Member of Ilda

    Stanwax Laser main distributor of First Contact in UK - like us on Facebook http://www.facebook.com/FirstContactPolymerCleaner
    www.photoniccleaning.co.uk

  3. #3
    mixedgas's Avatar
    mixedgas is online now Creaky Old Award Winning Bastard Technologist
    Infinitus Excellentia Ion Laser Dominatus
    Join Date
    May 2007
    Location
    A lab with some dripping water on the floor.
    Posts
    9,021

    Default

    What's your input on this? Can it get to the threshold for lasing with that?[/QUOTE]

    The only papers on dye lasers pumped by non laser sources used 6 kW of mercury arc.
    PM me and i'll get you the paper as a pdf, if I can find it in scitation. The problem is, can you flow the dye fast and smooth enough to get a optical grade dye jet. I can help you with that, I have some dye jets. Its a valid project, but you'll need to match the focused energy density of 6 kW of short arc lamps. Look up the term etendue, and if you can match the etendue that the arc lamp guys achived, you'll get a few mW of lasing. Your other problem is that the dye needs to be excited and the energy dumped in less then 200 nanoseconds, this means a flowing dye! If you leave it in the excitation region, you'll get triplett states, and these will quench lasing.

    Threshold for a coherent 590 dye laser in Rhodamine 6G is ~350 mW of all lines argon pump in a .6mm diameter beam.

    I just thought of something. You may have to work at it to borrow a rod, but how about green leds pumping alexandrite or yag? YAg has pump bands in the green and violet regions as well as IR. lower threshold then the dye and would run CW> Also dont count out showing "single pass gain". A common test used to teach students about lasers is to set up a hene tube (or diode pumped yag rod) with brewster windows at both ends but NO mirrors, you shine a chopped hene beam from another laser down the bore, and measure with a photodiode on a scope the difference between the bore light when the beam is chopped off, and the gain when the beam is on, plus measure the tube losses with the plasma off, and the difference is the single pass gain. If you can show single pass gain, your half way to lasing, and even if the LEDS are below lasing threshold, you might see some gain or amplification even if YOU DONT GET LASING!

    we have a single pass gain setup in SAM'S LASER FAQ. (I edit and write the gas laser chapters)

    I dont know if you could do it in the linear flashlamp pumped dye laser configuration, 220W is not anywhere near the number of joules, you'd have to pulse it. And in my experience, luxeon products dont hold up well to being overdrive pulsed, when your dad's company rates something for 350 mA, they usually mean it. Although with a good driver they do turn on in ~100 nS. I used to be a chief design engineer at a LED flashlamp company (1 patent) I'd build both flashlamp pumped (easy, plans were even published in scientific american) and led versions and try them both.


    Now, having sponsered about 30 students for Intel in the past few years, I know Intel will reward you for failure, if you do the project, spend the time and fail, and CAN EXPLAIN WHY< that is just as acceptable as a "successful" project. My sponsered kids have brought back over 250K$ in scholarships and prizes, so I know what I'm talking about. My boss lets me throw the resources of the university at the project, and we mentor the hell out of them, and they do well.

    How about 220 W of leds being used to look for minute amounts of water flow dye tracers, or leak detection. Might save a few fish.

    I have R6G, DCM, and kiton red if you need some.

    Start here: www.exciton.com they make dyes at reasonable prices.

    BTW, Ebay rhodamine and the big bottles from science suppliers are usually factory seconds, with lots of impurities, you need the pure laser grade stuff.

    Steve Roberts
    Last edited by mixedgas; 03-13-2008 at 08:25. Reason: I think too much as I type. or I cant type as fast as I thunk.

  4. #4
    Join Date
    Nov 2007
    Location
    Bend Oregon USA
    Posts
    3,348

    Default

    Quote Originally Posted by Laser Ben View Post
    As some of you may know, I am a high school student. Next year I am planning on entering the Intel Science Fair. I was thinking of making a LED pumped Dye laser. My problem is not the construction, I have a full CNC shop at my disposal and basically unlimited funds, I am wondering if I can actually get to the threshold needed. While I cannot tell you exactly what LEDs I will be using, I can tell you that it will be about 220W of optical light at the required pump wavelength. That is not the input power, but rather the optical power out of the LEDs. I was planning on having a flowing system for the dye in addition to water cooling the dye and LEDs.

    What's your input on this? Can it get to the threshold for lasing with that?

    You are correct...your problem is not the construction...its physics... LED's are a huge hurdle...I would start with laser diodes emitting green pumping r6g in a cell not a jet. IMHO If you want to enter it next year...better get started now. I am not saying you cant do it, but it will not be an easy quick project.

  5. #5
    mixedgas's Avatar
    mixedgas is online now Creaky Old Award Winning Bastard Technologist
    Infinitus Excellentia Ion Laser Dominatus
    Join Date
    May 2007
    Location
    A lab with some dripping water on the floor.
    Posts
    9,021

    Default

    Ben, here is a argon pumped 1064 nm YAG laser design, that should prove out the ND:YAG green adsorbtion bands.
    Its actually a bit stronger pumping then I thought, using green pumps. still keep in mind alexandrite, dye, yag, and maybe
    the red laser diode pumped near IR dyes. Also single pass gain seems like a winner to me.

    attachment is posted under the "educational use clause" for Ben's science project, and will be removed shortly.

    STEVE
    Attached Thumbnails Attached Thumbnails argonpmpdyag.pdf  

    Last edited by mixedgas; 03-13-2008 at 14:12.

  6. #6
    mixedgas's Avatar
    mixedgas is online now Creaky Old Award Winning Bastard Technologist
    Infinitus Excellentia Ion Laser Dominatus
    Join Date
    May 2007
    Location
    A lab with some dripping water on the floor.
    Posts
    9,021

    Default

    nice yag adsorption curve. I dont know if the mid red adsorption will lead to lasing, but I know the 808, blue-violet and green will.

    see here:

    http://www.vloc.com/PDFs/YAGBrochure.pdf

    Steve

  7. #7
    mixedgas's Avatar
    mixedgas is online now Creaky Old Award Winning Bastard Technologist
    Infinitus Excellentia Ion Laser Dominatus
    Join Date
    May 2007
    Location
    A lab with some dripping water on the floor.
    Posts
    9,021

    Default

    Not in pure yag, but here is a 671 nm pumped nd dopant laser

    see us patent 5200972

    Steve

  8. #8
    Join Date
    Nov 2007
    Location
    Bend Oregon USA
    Posts
    3,348

    Default

    if you have basically unlimited funds...start with this....almost everything you need...

    http://cgi.ebay.com/Spectra-Physics-...QQcmdZViewItem

  9. #9
    mixedgas's Avatar
    mixedgas is online now Creaky Old Award Winning Bastard Technologist
    Infinitus Excellentia Ion Laser Dominatus
    Join Date
    May 2007
    Location
    A lab with some dripping water on the floor.
    Posts
    9,021

    Default

    I will give you a dye jet, and have a friend who can sell you the resivoir, hp guages, dye cooling block and pump cheap from a CR590.

    If that quantaray includes the pump laser, thats a steal @ 2500

    Steve

  10. #10
    Join Date
    Jan 2007
    Location
    Florida
    Posts
    4,382

    Default

    Ben,
    Dye lasers require an extremely fast pump rise/fall time. That's why you cant use camera xenon flashlamps to pump them. A nitrogen laser will do.. I'm just wondering what the specs on the LEDs are?
    -BTW I PM'd you about the melles griot module-did you get it yet?
    Steve- I'm thinking about running the G-124s single polarity for simplicity..
    How much current can they take in the 4 ohm config?
    -Sorry i didnt mean to hi-jack this thread--
    Good luck Ben on the LED pumped Dye Laser--you might have invented something there..Good Luck

Posting Permissions

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