Photon upconversion

  1. I suppose this is a 2 part question.

    I saw a neodymium YAG laser being used for UV experiments at University of Portland a long time ago. They put the yellow-green light of the YAG through a piece of (I believe if memory serves me well enough) calcite crystal and it emerged as UV. Does the calcite crystal also work for 478nm wavelength?

    and

    Is there a relatively common material that will give photon upconversion in the 478nm wavelength region?
     
  2. jcsd
  3. DrDu

    DrDu 4,349
    Science Advisor

    I am not quite sure what you want: Double 478 nm or get 478 nm by frequency doubling?
    In the second case you might want to check the article on laser pointers in wikipedia, especially on blue laser pointers:
    http://en.wikipedia.org/wiki/Laser_pointer#Green
     
  4. I am looking to simply bring IR photons into the visible or uv wavelengths.
     
  5. Cthugha

    Cthugha 1,702
    Science Advisor

    In principle any material with significant birefringence can achieve that. I guess simple second harmonic generation is what you are looking for. As that is a non-linear effect, you may need high intensities and therefore need some balance between reasonable birefringence and a good optical damage threshold.

    Typical materials used for that purpose are lithium niobate, calcite and beta barium borate. KTP and LBO work just as well. The last few materials should be easy to get. It works at 478 nm. However, the key to second harmonic generation is phase matching inside the crystal, so you need a crystal which is cut in a certain way.
     
    Last edited: Jun 30, 2014
  6. UltrafastPED

    UltrafastPED 1,918
    Science Advisor
    Gold Member

    You may have seen a Continuum Minilite:
    http://www.quantronixlasers.com/ind...ent&view=article&id=648&Itemid=576#liintroTab

    The YAG generates 1064 nm light; by inserting the appropriate crystals and dichroic mirrors it can be shifted to 532 nm, 355 nm, or 266 nm. There is loss of power with each conversion.

    I used one of these a few years ago; I don't recall what type of crystals were used. On earlier projects I used BBO to shift from 780 nm to 390 nm, and a second crystal to convert that to 260 nm.

    You can contact any of the optics houses for guidance on selecting appropriate crystals for a particular type of laser; for example: http://www.redoptronics.com/BBO-crystal.html
     
  7. The answers you both have provided, answered my question very well. Thank you.
    390nm would be great. 450 nm would be ideal.

    Of the options mentioned, which provides the greatest efficiency?
     
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