Two-Photon Absorption Calculator
Calculate Two-Photon Absorption
About Two-Photon Absorption
Two-photon absorption (TPA) is a nonlinear optical process where two photons are simultaneously absorbed by a molecule, promoting it to an excited state. It's widely used in microscopy and photonics.
Two-Photon Cross-Section:
σ₂ = (I × τ × A) / (E² × N)
Absorption Coefficient:
β = σ₂ × C × I
Fluorescence Rate:
R_fluor = σ₂ × Φ × I² × C
Where:
- σ₂ = Two-photon cross-section (GM)
- I = Light intensity (W/cm²)
- τ = Pulse duration (s)
- A = Beam area (cm²)
- E = Pulse energy (J)
- N = Number of molecules
- Φ = Fluorescence quantum yield
Applications:
• Two-photon microscopy
• Photodynamic therapy
• Optical data storage
• Nonlinear optics
Advantages:
• Deep tissue penetration
• Reduced photodamage
• High spatial resolution
• 3D imaging capability
Two-photon absorption is crucial in modern microscopy techniques, enabling deep tissue imaging with minimal damage.