The nature of light has been a subject of inquiry since antiquity. In the seventeenth century, Isaac Newton performed experiments with lenses and prisms and was able to demonstrate that white light consists of the individual colors of the rainbow combined together. Newton explained his optics findings in terms of a "corpuscular" view of light, in which light was composed of streams of extremely tiny particles traveling at high speeds according to Newton's laws of motion.

Photoluminescence is a process where a molecule absorbs light energy and re-emits it in the form of light. This phenomenon occurs when a substance absorbs photons, promoting its electrons to higher energy level excited states, followed by a relaxation process in which the electrons return to their original ground state energy levels and emit light. Photoluminescence is widely observed in various materials, including semiconductors, and organic and inorganic compounds.
A pair of electrons in a...

Total internal reflection fluorescence microscopy or TIRF is an advanced microscopic technique used to visualize fluorophores in samples close to a solid surface with a higher refractive index, such as a glass coverslip. TIRF only allows fluorophores in proximity to the solid surface to be excited. When light from a medium with a lower refractive index (such as air) hits the glass coverslip at a critical angle, the light undergoes total internal reflection stead of passing through the glass.

Constrained by limited energy and resources, organisms must compromise between offspring quantity and parental investment. This trade-off is represented by two primary reproductive strategies; K-strategists produce few offspring but provide substantial parental support, whereas r-strategists produce much progeny that receives little care. These strategies are related to an organism’s survival likelihood across its lifespan, which is represented by a survivorship curve. Three general types of...

The energy required to carry out photosynthesis is light— typically electromagnetic radiation from the sun. The range of all possible wavelengths is known as the electromagnetic spectrum.
Photons
A photon is a discrete electromagnetic particle or bundle of energy. Photons are characterized by their frequency, wavelength, and amplitude, similar to the properties of a wave. Waves with higher frequencies transmit more energy and have shorter wavelengths than longer wavelengths that transmit less...

Fluorometers and spectrofluorometers are two types of instruments used for measuring molecular fluorescence. These instruments differ in how they select excitation and emission wavelengths and the type of light sources they utilize. Fluorometers use absorption interference filters to choose excitation and emission wavelengths. The excitation source in a fluorometer is typically a low-pressure mercury vapor lamp that emits intense lines distributed throughout the ultraviolet and visible regions.