Amplified spontaneous emission

Amplified spontaneous emission (ASE) is a process where light naturally emitted by excited atoms or molecules within a material is amplified as it travels through, producing a stronger, more coherent beam. Unlike laser light, ASE doesn’t originate from a specific, controlled source, but from the random emission of photons in all directions. When the emitted light passes through a medium with a high enough gain, it stimulates more emissions, increasing the intensity. ASE is important in various optical devices, such as fiber amplifiers and laser systems, and can influence their performance by adding background noise or serving as a precursor to laser action.