Luminescence effects:
Luminescence (Latin word lumen = light) is a body’s ability to emit light when illuminated by a light source.
Scientifically speaking, luminescence is the optical radiation of a physical system produced during the transfer from an excited condition to a basic condition. Light emission is triggered by excitation in the UV, IR or visible light range.
Phosphorescence and fluorescence:
Luminescence can be divided into two phenomenons: phosphorescence and fluorescence. In phosphorescence,
the body continues to light up even if it is no longer illuminated.
Fluorescence is the ability of certain chemical substances to absorb shortwave light energy and reflect it seemingly simultaneously as longwave light: for example, invisible, short-wave, high-energy daylight portions (e.g. UV light or X-rays), are absorbed first and then stored for a more or less long period of time; they then excite electrons for quantum leaps into a higher energy level and finally emit light of less energy and greater wavelength in the visible range when these electrons return to their previous, lower energy level.
Luminescence and illumination are closely related: if the body is no longer illuminated, luminescence will disappear.
Autofluorescence, primary and secondary fluorescence are variations of fluorescence. Fluorescence is sometimes called photoluminescence.
When a chemical reaction releases energy, it can also appear as light: in other words, chemoluminescence or chemical light. One familiar example of this is luminol, used by police departments, that lights up bluish green in the presence of blood.
One particular type of chemoluminescence is bioluminescence, i. e. the ability of living creatures to produce light either on their own or with the help of symbionts.
Coral fluorescence in close-up
This video shows various scleractinian corals under narrow-bandwidth blue light, which excites the fluorescent proteins in the epidermis of the animals. Fluorescence is a phenomenon where an object absorbs light of a particular wavelength (colour), and emits it at another wavelength (colour). It is still not clear why corals produce fluorescent proteins, but it seems to protect them from harmful UV-radiation and excess (sun)light.
Using time-lapse, the contractile and expansion behaviour of coral polyps is also visualized in this video.
Arizona Bark Scorpion (Centruoides sculpturatus) under UV light
The Arizona Bark Scorpion, Centruoides sculpturatus, illuminated by UV light while filmed with a UV filtered Sony DCR-TRV80. Night shot was not used; the green color is the fluorescent emmission.
Underwater fluorescence disco - Oceans - BBC
Using a yellow filter as "band pass filter"
Phillipe Coustaeau and the team dive in the Red Sea, one of the warmest seas in the world. Despite the warm temperatures, coral reefs flourish with their flourescent pigmentation putting on an amazing show of technicolour. Fantastic clip taken from the BBC Oceans series.
AEQUOREA
Water Jellies Fluorescing Under Black Light
The water jelly (Aequorea sp.) glows green because it has a protein called the green fluorescent protein (GFP). This protein produces fluorescence, which occurs when we shine one colour of light (usually UV or black light) on a protein or organism and see another colour come out (in this case, green).