LASER BEAM QUALITY, ENTROPY AND THE LIMITS OF BEAM SHAPING

摘要

The paper presents a thermodynamical and quantum-statistical analysis of the electromagnetic field with the aim of deriving the entropy of partially coherent thermal and laser beams. Together with the second law of;thermodynamics the knowledge of the entropy allows the discussion of the limits of beam shaping. It will be shown that in many cases a multi-(transversal) mode laser beam can be shaped into a multi-(longitudinal) mode beam with M(2) = 1. [References: 18]