Pulsed laser diodes with a homogeneous beam profile
Pulsed laser diodes are becoming more and more efficient and powerful and they represent a viable alternative to large and expensive laser systems. One advantage of solid-state lasers is the excellent beam profile. Achieving this with semiconductor laser diodes requires the use of external beam-shaping elements or homogenisers.
Diffusing lenses, diffractive elements, or long optical fibres can be used, however this always results in either a loss of power or too great a mechanical effort.
Laser Components developers in Canada have been successful in connecting powerful, multi-junction PLDs to a special fibre structure and allowing a homogeneous beam profile to be achieved after just a few centimetres. The picture shows the near-field distribution of a pulsed laser diode with three epitaxially-integrated emitters. After just 13mm, a significantly more homogeneous beam profile is visible.
The advantage of this assembly is that it is compact and robust and exhibits low losses at the same time as a higher peak power. Prototypes are currently being built.