That's why it's called spontaneous emission you cannot control it. But there is a kind of emission which is called stimulated emission emission. People use stimulated emission in lasers and it can be controlled.

Microwave Amplification by Stimulated Emission of Radiation

Laser is short of light amplification by stimulated emission of radiation.

stimulated emission causes due to the energy difference between the higher and lower energy level state, but it doesn't depends in the case of spontaneous emission . spontaneous emission causes without any stimulation .In stimulated emission energy transfer is twice the energy transfer of spontaneous emission.

LASER- light amplification by stimulated emission by radiation

SASER - sound amplification by stimulated emission by radiation