In the process of stimulated emission, how are the emitted photons characterized?

In the process of stimulated emission, emitted photons are characterized by being in the same phase and of the same wavelength. This phenomenon is essential to the operation of lasers. When an excited atom or molecule returns to a lower energy state, it can stimulate the emission of a photon from another excited atom. The crucial aspect of this process is that both emitted photons will have identical properties, meaning they will have the same phase relationship and the same wavelength.

This uniformity is what gives laser light its coherence, allowing it to be concentrated into a narrow beam with low divergence. Coherence refers to the property where the emitted light waves maintain a constant phase relationship over time, which is a hallmark of laser light compared to the more random phases of light from other sources. The matching wavelength contributes to creating a monochromatic beam of light, essential for various applications of lasers, including telecommunications and medical procedures.