Two Photon Absorption Calculator

Two-Photon Absorption (Intensity)

Estimate peak intensity for pulsed lasers (simplified).

2026-05-06T10:07:27.573Z
mW
MHz
fs
μm

Peak Intensity (I₀)

3.9789e+13 W/m²

I₀ = P_avg / (f × τ × π w₀²)

About Two-Photon Absorption

Two-photon absorption (TPA) is a non-linear process where two photons are absorbed simultaneously. The probability of TPA is proportional to the square of the light intensity, making it highly localized in the focal volume of a laser beam.

How to use

Provide average power, repetition rate, pulse width, and spot radius to estimate peak intensity for pulsed lasers. This is a simplified estimate.

Example

100 mW, 80 MHz, 100 fs, 10 μm → I₀ on the order of 1e12–1e14 W/m² (example depends on parameters).

FAQs

Q: Is this the TPA cross-section? A: No — this is peak intensity. Q: Use in experiments? A: This is an order-of-magnitude estimate; consult material data for true cross-sections.

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