Advances in GaN laser diodes for quantum sensors and optical atomic clocks

Quantum technologies containing key GaN laser components will enable a new generation of precision sensors, optical atomic clocks and secure communication systems for many applications such as next generation navigation, gravity mapping and timing since the AlGaInN material system allows for laser diodes to be fabricated over a wide range of wavelengths from the u.v. to the visible. We report our latest results on a range of AlGaInN diode-lasers targeted to meet the linewidth, wavelength and power requirements suitable for optical clocks and cold-atom interferometry systems. This includes the [5s(2)S(1/2)-5p(2)P(1/2)] cooling transition in strontium(+) ion optical clocks at 422 nm, the [5s(2)(1)S(0)-5p(1)P(1)] cooling transition in neutral strontium clocks at 461 nm and the [5s(2)s(1/2) - 6p(2)P(3/2)] transition in rubidium at 420 nm. Several approaches are taken to achieve the required linewidth, wavelength and power, including an extended cavity laser diode (ECLD) system and an on-chip grating, distributed feedback (DFB) GaN laser diode.