What does od mean?

OD is short for optical density, which stands for optical density. OD means that when light passes through a sample, some light will be absorbed. Therefore, in physics or chemistry, people prefer to use absorbance to represent phenomena; In spectroscopy, transmittance is the ratio of the intensity of outgoing light to the intensity of incident light.

Measure the ability of refractive index medium or optical element to slow down or delay light transmission. It measures the speed of light of matter, which is mainly influenced by the given wavelength of light. The slower the speed of light passing through a given medium, the higher the optical density of the medium.

Extended data:

Although both optical density (OD) and absorbance can measure the absorption of light when it passes through an optical element, these two terms are different. Optical density measures the attenuation or loss of light intensity when light passes through an optical element. Optical density focuses on detecting the attenuation of light after scattering, while absorbance only considers the absorption rate of light in optical elements or media. Optical density and absorbance (absorbance) can be detected by using a spectrometer.

Optical equipment plays an important role in various modern technologies. Such as CD, DVD and Blu-ray players, optical fiber cable boxes and optical components. They are even useful in some biological laboratories and can be seen in some microscopes and spectrometers. When studying the science behind these devices, it is easy to confuse optical density and absorption rate, because they both measure the amount of light "absorbed" when light passes through optical elements, but there are some subtle differences between these two terms.