A class of nonlinear absorbers in which the excited state absorption is large compared to the ground state absorption can undergo a process called reverse saturable absorption (RSA), also known as reversible saturable absorption. In contrast with saturable absorption (SA), when the absorptive properties of SA material fade with increasing the intensity due to depletion of the ground state, RSA can result in large absorption by the nonlinear absorber at high incident laser energies and low absorption at low laser energies. The performance of such nonlinear materials can be limited by the accompanying linear absorption at low input energy. However, transparency at low input energy, but high absorption at high input energy can be achieved with multi-photon absorbers (MPA) in which two or more photons are absorbed simultaneously.

See also: Saturable absorption, Energy level, Energy level diagram, Single-photon absorption, Two-photon absorption, Three-photon absorption, Multi-photon absorption, Relaxation

SimphoSOFT logo SimphoSOFT® supports simulation of reverse saturable absorption. User can define an unlimited number of energy levels and absorption transitions (from the ground as well as excited states).

SimphoSOFT® can be purchased as a single program and can be also configured with Energy Transfer add-on ET add-on, Multi-Beam add-on Multi-beam add-on, Optimization add-on Optimization add-on, Z-scan add-on Z-scan add-on, and MPA Info+ add-on MPA Info+ add-on for an additional charge. Please, contact our sales staff for more information
  • e-mail
  • phone: +1 (973) 621-2340
You can request a remote evaluation of our software by filling out online form -- no questions asked to get it, no need to install it on your computer.