WHAT IS FLUORESCENCE
Welcome to the fascinating world of fluorescence. The invisible ultraviolet rays can turn a dull piece of stone in an explosion of light in every color of the rainbow. How is this magical process ossible I will try to explain in this chapter. We will elaborate on how this can happen, talk about the everyday applications of fluorescence hazards, causes, lights and of course you can see some minerals in the photo gallery on this site.
What is Fluorescence? Fluorescence is light emission by certain substances when are activated by ultraviolet energy. The emission disappears if the activation (lightsource) is removed. Fluorescence comes from the mineral fluorite, which in early 1850 was observed that the blue glow was caused by the sun. (Sir George Stokes)
What is light? To understand fluorescense, it is necessary that we first see what light is. Light is a type of electromagnetic radiation emitted by the sun. Electromagnetic radiation which occurs in various wavelengths. The wavelength is measured in nanometers (nm. = 1 / millionth of a millimeter). In the figure below, you can find a schedule. We will identify the types of radiations from right to left.
Radio waves are similar to light only is their wavelength longer. After them come the Microwaves, which are commonly used in radar and, for example, in the microwave to heat the food from the inside. Then you get Infrared radiation, which is used in the remote control. Infrared is abbreviated as IR, people feel it as heat.
Next is the the visible light, this means that we humans can see this light with our eyes, all colors so. Light is made up of different colors. All colors have different wavelengths. With wavelength means the distance between two crests of waves, as you see in water. The color of an object is determined by the frequency (wavelength) of the electromagnetic radiation that reflects it back. A black object absorbs all wavelengths of visible light. A red object absorbs all but the red radiation.
Then comes the ultraviolet light called UV light, thereby we become brown as we lie in the sun. The ozone layer that largely keeps to, but the attack is more and more UV inside, and it can be harmful, so it is unhealthy to lie long in the sun. The X-rays, these are widely used in medical science. Last come the gamma rays, these rays are harmful to all living beings, and among others is released by nuclear power plants and uranium from, for example, gamma rays have the shortest wavelength, so the highest energy value. ultraviolet light Ultraviolet radiation is in the above scheme, therefore, for the visible light. Thus, the energy value is higher.
The wavelengths range from 100 nm. to 400 nm. We can divide ultraviolet light into four areas, as can be seen in the following figure. The long wave radiation in the range of 315 to 400 nm. (Also referred to as UV-A).
The radiation around the 300-310 nm. (UV-B) causes a photochemical reaction in the skin, which we experienced as sunburn. The production of vitamin D also is done under the influence of this radiation. The short wave radiation is the range of 200 to 280 nm. (UV-C) but will not achieve under normal circumstances. This radiation is stopped by the atmosphere. It is also this radiation (from below 300 nm.), Which has a bactericidal effect, so that it is frequently used in the food industry. Vacuum ultraviolet light is the last area, and not of importance for use in minerals. It must be applied under vacuum because ordinary air already retaining the radiation.