Two-Photon Absorption Spectroscopy

Two-photon absorption (TPA) is a third order nonlinear optical phenomenon in which a molecule absorbs two photons at the same time. The transition energy for this process is equal to the sum of the energies of the two photons absorbed. The probability that a molecules undergoes two-photon absorption depends on the square of the intensity of the incident light, if the two photons are from the same beam (in the case of two incident beams, the transition probability depends on the product of the beams intensities). This intensity dependence is at the origin of the interest in two-photon absorbing materials for use in microscopy and microfabrication applications.
For more information see the photonicswiki:
photonicswiki.o...

[@cmditr]

In our setup we use optical parametric amplifier (TOPAS-C) from Light Conversion. It is also possible to select desired wavelength from white-light supercontinuum using either liquid crystal dynamic filters or use narrowband filters mounted on a computer-controlled motorized filter wheel.

[@celestialruby888]

Might it be possible to construct a photon image of any picture? I am trying to construct affordable software that interacts with photon images and can interact with ones biological body using 2 way photon communication.

[@ashamonineog8295]

Is pulsed laser is necessary ?
Why do we use this?

[@A3racada3ra]

Because you need high photon densities for two-photon effects, which are easily achieved by using fs-pulses and focussing them on the sample.

[@aniksamiurrahman6365]

I'm wondering if there was any CoD fan in his lab.