Total internal reflection
Reflection within a medium if the angle of incidence on the boundary surface of a ray of light is larger than the critical angle for total internal reflection.
Transparency of a medium to optical radiation. Designates the portion of the incident radiant flux that emerges again after traversing the sample. Transmission is quantified by the spectral internal transmittance.
Also called transparency. Property of liquid, solid or gaseous substances that enables light to pass through them partially or totally. The spectral internal transmittance is the ratio of transmitted radiant flux to the incident flux.
Also called transmittance. Property of liquid, solid or gaseous substances that enables light to pass through them partially or totally. The spectral internal transmittance is the ratio of transmitted radiant flux to the incident flux.
are used for fluorescence measurements. The cross-sectional area is triangular in shape. The excitation beam hits the hypotenuse area while the fluorescent light is detected at right angles to the incident ray of light.
Reduction of the optical range in a transparent medium by scatter radiation and absorption caused by optically denser inclusions, e.g. particles. This phenomenon is quantified by the turbidity value.
A measuring procedure to determine the concentration of suspended particles in a liquid medium. This procedure does not measure the intensity of the scattered light, but the intensity decrease of the primarily radiated light.
The turbidity value quantifies the qualitative phenomenon of turbidity. The objective of the turbidity measurement is to obtain information on the concentration of scattering particles.
“The intensity of light scattered at the particles is proportional to the number of particles in a unit volume and thus also proportional to their concentration.”