750 nm direct emitting MECSELs and VECSELs towards isotope separation applications for nuclear medicine

A vertical-external-cavity surface emitting lasers (VECSEL) is a versatile laser type, which can deliver high-power, high-quality beam in an extremely broad wavelength range, from UV to mid-IR. VECSELs have been proven as eligible and reliable light sources meeting the strict requirements of applications in the atomic and molecular (AMO) physics. A recently invented method of magnetically activated and guided isotope separation (MAGIS) is a key solution for resolving the worldwide long-term radioisotope shortage in nuclear medicine. For each of the about 150 isotopes the MAGIS method can separate, it relies on one certain laser light source. A 750 nm VECSEL can be used for producing Technetium-99m radioisotope, which is considered to be the most common radioisotope and used in tens of millions diagnostic procedures annually.
Typical required power level for the VECSEL’s applications in the AMO and nuclear medicine lies in the multi-watt range. Conventional VECSELs are capable of delivering tens of watts. However, visible wavelength VECSELs suffer from a heat excess in the active region due to the pump light absorption in the DBR, which challenges achieving laser operation. The novel concept of a semiconductor membrane-external-cavity surface-emitting laser (MECSEL) is a promising solution overcoming the heat excess problem at the challenging visible wavelengths and allows further power scaling. Strategies to create gain structures for VECSELs and MECSELs aiming on direct laser emission at 750 nm will be presented.