What is the difference between spontaneous emission and stimulated emission

Therefore, more electrons tend to absorb energy and excite themselves. But after this process of excitation, as mentioned above, electrons cannot be in the excited states forever as any system favours being in a lower energy stable state rather than being in a high energy unstable state.

Therefore, excited electrons tend to release their energy and return back to the ground levels. It is solely a measure of bringing the system to a more stable state. When a spontaneous emission occurs, as the electron transitions between the two energy states, an energy packet to match the energy gap between the two states is being released as a wave.

Therefore, a spontaneous emission can be projected in two main steps; 1 Electron in an excited state comes down to a lower excited state or ground state 2 The simultaneous release of an energy wave carrying energy that matches the energy gap between the two transitioning states.

Fluorescence and thermal energy are released this way. This is the other method in which emission takes place when an electron transitions from a higher energy level to a lower energy level or to the ground state. However, as the name suggests, this time emission takes place under the influence of external stimuli such as an external electromagnetic field.

Radiations are in random direction , phase and wavelength Radiations are coherent , monochromatic and in same direction.

Independent of outside circumstances Dependent of outside circumstances No metastable state exist Metastable state exist Number of photons emitted are less Number of photons emitted are more.

Like 0 like. What is lowest current at which stimulated emission exceeds spontaneous emission in a semiconductor laser called? Stimulated emission takes place only when the gain medium is pumped strongly enough and population inversion is created, while spontaneous emission takes place no matter population inversion exists or not.

Figure 1: Spontaneous and stimulated emission. Properties of photons Properties of photons generated by spontaneous and stimulated emission are quite different.