1. Infrared radiation sources

1.1 Radiation emission

Thermal emission from matter is one form of light-matter interaction. Using "Einstein coefficients" reasoning on a simple two-level system, E ₁ and E ₂ at temperature T, in the presence of a set of photons whose spectral volume energy distribution is characterized by Φ _eq (ν ₁₂ ,T) at frequency ν = ν ₁₂ (figure 1 a), we can place thermal emission in a framework common to three kinds of interaction: absorption,...