Final answer:
Immediate emission of light under stimulation refers to 'stimulated emission,' a process where an excited atom or molecule emits a photon in response to encountering a photon of the same frequency, leading to laser technology. Different from stimulated emission, 'fluorescence' is when a material emits light at a different wavelength after being excited.
Step-by-step explanation:
The immediate emission of light under stimulation is an interesting phenomenon in physics called stimulated emission. When a material or atom is in an excited state and is stimulated by a photon of the same frequency, it can emit a second photon, which has the same wavelength, phase, and polarization as the stimulating photon. This principle is at the core of laser technology. Materials that exhibit this behavior are used in various applications, including scientific research and medical devices. In contrast, if the material emits light at a different energy level in multiple smaller steps, the process is called fluorescence, which is also stimulated by energy inputs like UV photons but results in the emission of light at a different wavelength. Both stimulated emission and fluorescence are essential in understanding light-matter interactions and have vast applications in modern technology.