Jun 19 2014
Beam combining is done through a number of processes in order to scale up the power and radiance of laser sources. There are a number of techniques that allow the build up of high power laser sources that result in high beam quality and high brightness.
Beam combining incorporates the output of a number of laser sources so that a single, high-power laser output is achieved. Three main techniques that are used for laser beam combining are side-by-side beam combining, spectral techniques and phased array techniques. It is important to note that the geometric attributes of the multiple laser beams remains unaltered during beam combining.
Types of Beam Combining
The various techniques of beam combining are elaborated in the following sections.
Side-by-side combining – In this method, the array elements do not operate at the same wavelength. Conventional laser diodes fall into this category. This method, however, does not yield an output beam that has a higher radiance when compared to the input beams.
Coherent beam combining – Also called the phase array combining. In this method, all the array elements operate with the same spectrum and the relative phases are controlled by constructive interference.
Spectral beam combining – Often referred to as wavelength beam combining. The array elements operate at different wavelengths and a dispersive optical system is used to overlap beams in the near and far fields.
Applications
Combined laser beams are capable of producing tens to hundreds of watts of power. They are typically useful in military and long-distance optical applications.
Sources and Further Reading