Photon Upconversion: Neodymium YAG Laser & 478nm Wavelength

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Discussion Overview

The discussion revolves around photon upconversion using a neodymium YAG laser, specifically focusing on the potential for achieving UV light from a 478nm wavelength. Participants explore materials and methods for frequency doubling and the characteristics of various crystals suitable for this purpose.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant recalls observing a neodymium YAG laser used for UV experiments and questions whether calcite crystals can also convert 478nm light to UV.
  • Another participant seeks clarification on whether the goal is to double the 478nm wavelength or achieve it through frequency doubling.
  • A participant expresses a desire to convert IR photons into visible or UV wavelengths.
  • It is suggested that materials with significant birefringence can achieve second harmonic generation, requiring high intensities and careful phase matching within the crystal.
  • Common materials for this purpose mentioned include lithium niobate, calcite, beta barium borate, KTP, and LBO, with a note that these can work at 478nm.
  • A participant provides information about the Continuum Minilite laser, detailing how it generates 1064nm light and can be converted to shorter wavelengths using specific crystals, although they do not recall the exact crystals used.
  • One participant expresses satisfaction with the responses received and inquires about which mentioned options provide the greatest efficiency for achieving 390nm or 450nm wavelengths.

Areas of Agreement / Disagreement

Participants have not reached a consensus on the most efficient method or material for achieving photon upconversion at 478nm, and multiple competing views and approaches remain in the discussion.

Contextual Notes

There are unresolved considerations regarding the specific requirements for phase matching in crystals and the efficiency of different materials in achieving the desired wavelength conversions.

BernieM
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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?
 
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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
 
I am looking to simply bring IR photons into the visible or uv wavelengths.
 
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.
 
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You may have seen a Continuum Minilite:
http://www.quantronixlasers.com/index.php?option=com_content&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
 
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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