Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Monochromatic to Polychromatic Laser beam

  1. Jul 29, 2010 #1
    Is it possible to widen the spectral FWHM of a laser beam.

    Any ideas?

    I understand the lasing process leads to the monochromaticity, but such a intense light source can have other uses.

  2. jcsd
  3. Jul 29, 2010 #2
  4. Jul 30, 2010 #3
    There isn't anything is the wiki article about laser halfwidths.
    I'm talking about a laser with a few nm halfwidth.
  5. Jul 30, 2010 #4


    User Avatar
    Science Advisor

    What you could do, is let the beam pass through a gas that fluoresces at the laser's wavelength, which would lead to some pressure/collision broadening, which you could control with temperature/pressure of the gas.
  6. Jul 30, 2010 #5
    If you can deal with laser pulses instead of continuous beams, you can then shorten the pulses to the femtosecond regime.

    In this range, the shorter the pulse, the wider its spectral FWHM.
  7. Aug 5, 2010 #6
    I like the idea of using a gas for collisional broadening. Any ideas on the type of gas? Maybe for a green Nd:yag(532nm) laser. Would anything be wrong have the beam pass through a coloumn, which contains the gas and controls the pressure.

    A concern would be that there are alot of different spectral broadening effects, http://en.wikipedia.org/wiki/Spectral_line#Spectral_line_broadening_and_shift". so to either control or predict the amount of broadening would be a task.

    Anyone have any ideas of similar research or key search words for the process described.

    Last edited by a moderator: Apr 25, 2017
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook