Using the two-photon absorption calculator, you can find the amount of two-photon excitations per molecule given a Gaussian beam laser source.
In this short article, we will explain:
- What two-photon absorption is; and
- The two-photon absorption equation.
Keep reading to learn more!
What is two-photon absorption?
Two-photon absorption is a phenomenon discovered by Maria Goppert-Mayer in 1931. In this scenario, an atom or molecule absorbs two photons at once, taking the particle from the ground state ()to a higher virtual energy state ().
Two photon absorption equation
The two-photon absorption calculator finds the number of two-photon excitations per molecule by using the following formula:
- – Cross-section in GM. One GM is ;
- – Exposure time; and
- – Photon flux at the center of the Gaussian beam.
Finding two-photon excitations number without photon flux
You'll notice the two-photon absorption calculator has a few other parameters.
These come in handy if you don't know since you can calculate it with the following equation:
- and are the photon's frequency and wavelength, respectively;
- is the beam's intensity; and
- is the speed of light.
And we can write the intensity using its and beam radius as:
Lastly, we can replace the beam radius with the laser's full width at half-maximum (FWHM) value:
Using the two photon absorption calculator
Let's assume we have the following data:
- for a given laser.
This is all we need to find the number of two-photon excitations according to the two-photon absorption equation.
We can plug that information into the calculator to find that .