Institute of Applied Physics of RAS

New methods for the synthesis of highly localized configurations of the optical field using coherent beam combining

Aim: to develop and study methods for creating high-intensity, sharply focused laser fields using coherent beam addition in a fiber-optical system with many channels. As one of the promising concepts on the way to creating laser systems with ultra-high peak intensity, the idea is based on the coherent addition of beams from a large number (hundreds and thousands) of fiber amplifiers of chirped pulses. This concept allows you to get a revolutionary increase in the repetition rate of super-power systems due to the efficient distribution of thermal loads, while the existing systems currently operate in a one-time or rarely periodic mode, which is associated with the fundamental difficulties of removing heat from active elements.

1. Development of a multichannel frontend laser system with controllable channels
2. Development of a coherent combining system
3. Study of coherent combining of beams in a focusing system.
4. Investigation of the possibility of realizing and controlling the localized field structures using inhomogeneous distribution of polarization


A scheme for coherent combining of beams of fiber amplifiers in the far field is developed. An optoelectronic circuit has been developed for detecting and stabilizing the phase of several high-power laser beams relative to one reference beam, which maintains the phase at a level of l/100 in the frequency range up to ~ 1 kHz. The circuit is based on standard commercially available components.

A new effective method of coherent combining of many emitters located in one plane and having a low fill factor over the aperture (for example, radiation from an array of densely packed single-mode optical fibers) is proposed. The method makes it possible to obtain more than 98% efficiency of coherent combinig, which is unattainable in known schemes for a given configuration of optical sources.

A theoretical study of quantum features of coherent beam combining is carried out. The standard quantum noise limit for radiation resulting from coherent combining of beams with a feedback system is found.

 C.R. Muller, F. Sedlmeir, V.O. Martynov, Ch. Marquardt, A.V. Andrianov, G. Leuchs, “The standard quantum limit of coherent beam combining,” New Journal of Physics 21, 093047 (2019)