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Two photon absorption in silicon

  1. May 18, 2006 #1
    How does work the two-photon absorption ?

    Does it exist a Beer-Lambert law for this kind of process?
    If yes, does someone know where i could find the order of magnitude of two-photons absorption coefficient for silicon at 1500 nm ?

  2. jcsd
  3. May 18, 2006 #2

    Claude Bile

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    Nonlinear absorption of this sort occurs for very high laser intensities, typically, for the infrared at least, one needs to blast silica with at least a nanojoule femtosecond pulse to observe these effects.

    The two-photon absorption in silica at the kind of intensities you are likely to find from a 1500nm source, the TPA would be negligibly small.

    Last edited: May 18, 2006
  4. May 19, 2006 #3
    The source we are using is the "classic" Tsunami-Opal femtosecond line. We then have at 1500nm a relatively high peak intensity, that's why i would like to evaluate two-photon absorptions.
  5. May 19, 2006 #4


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    2 photon absorption coeff in Si : 0.45 cm/GW at 1540 nm

    Tsang et al, App Phys Lett, 80, 416 (2001)
  6. May 21, 2006 #5
    Thanks a lot
  7. May 21, 2006 #6

    Claude Bile

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    Fair enough :blushing: . I never considered 1500 nm to be within your typical window of femtosecond pulse generation, but it appears I was wrong.

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