What is Fluorescence?
Fluorescence is the emission of light by a substance that has absorbed light or other electromagnetic radiation. It's a form of luminescence, typically visible and initiated by ultraviolet radiation.
History of Fluorescence
The phenomenon of fluorescence was first observed by Sir George Stokes in 1852. He named it after the mineral fluorite, which exhibited a distinct glow when exposed to ultraviolet light.
Fluorescence vs. Phosphorescence
Unlike fluorescence, where emission ceases almost immediately after the excitation source is removed, phosphorescence can continue for minutes to hours due to a delayed quantum transition.
Biological Fluorescence
Some organisms exhibit biofluorescence. Corals and jellyfish use fluorescent proteins for protection and communication. These proteins have been pivotal in biomedical imaging and research.
Applications of Fluorescence
Fluorescence has diverse applications, including mineralogy, forensic science, and art restoration. It's instrumental in detecting counterfeits and analyzing chemical and biological substances.
Quantum Yield of Fluorescence
Quantum yield measures the efficiency of fluorescence, defined by the ratio of photons emitted to photons absorbed. Higher quantum yield indicates a more efficient fluorescent material.
Fluorescent Lighting Technology
Fluorescent lights function by emitting UV light when electricity excites mercury vapor. The UV light then excites a phosphor coating inside the bulb, emitting visible light.Diamonds Fluoresce Under UV
Approximately 30% of diamonds exhibit fluorescence, glowing blue under ultraviolet light, affecting their perceived color and value.
What initiates fluorescence typically?
Visible light absorption
Ultraviolet radiation exposure
Infrared radiation exposure
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