Strahlstärke

Strahlstärke, also known as radiant intensity, is a photometric measure of the amount of light radiated by a point light source in a particular direction. It quantifies the power emitted per unit solid angle. The SI unit for radiant intensity is watts per steradian (W/sr). In simpler terms, it tells you how bright a light source appears to be in a specific direction, taking into account both the total power output and how focused that power is.

The concept is crucial in understanding how light propagates from sources like LEDs, lasers, or even stars. A higher strahlstärke in a certain direction means more luminous power is being directed towards that area. It's distinct from luminous intensity, which is measured in candelas and accounts for the human eye's sensitivity to different wavelengths of light. Radiant intensity, on the other hand, deals with the physical power of the radiation itself, irrespective of perception.

Calculations of strahlstärke often involve integrating the spectral radiance over the relevant wavelength range and dividing by the solid angle. This measure is vital in fields such as optical engineering, lighting design, and astrophysics, where precise knowledge of light distribution is essential for performance and analysis.