Terms for subject Optics

German	English
spektrale spezifische Lichtausstrahlung	spectral radiance (the radiance of a source may vary with wavelength and the spectral radiance is defined as the radiance per unit wavelength interval)
spezifische Lichtausstrahlung	L (luminous flux radiated per unit area of the surface in all directions)
spezifische Lichtausstrahlung	radiance (radiometric quantity; it is a measure of the brightness of a radiating surface; it is defined as the radiant energy emitted in a specified direction per unit time, per unit projected area of surface, per unit solid angle; it is measured in watts per steradian per square centimetre or square metre)
spezifische Lichtausstrahlung als Funktion der Wellenlänge	radiance as a function of wavelength (Nλ)