Laser‐Verstärker und Phasenunschärfe

Abstract

Extending recent calculations of G LASSGOLD and H OLLIDAY [3] the amplification process by means of a laser amplifier is treated theoretically in case of an arbitrary quantum mechanical state of the incident electromagnetic field. An explicit expression for G LAUBER 's P ‐function representing the state of the field after amplification, is found. Interpreting this function as a classical distribution function for the complex amplitude of the field, a distribution function W (φ; t ) for the phase is obtained by averaging over the real amplitude. With the help of W (φ; t ) the phase uncertainty (δφ) 2 for the amplified field is calculated. The result approximately agrees with the expression for(δφ) 2 following from the phase operator originally introduced by H EITLER if applying it to the incident field. Thus a connection between the phase operator and an experimental arrangement is established.