With an emission bandwidth approaching an octave, titanium-doped sapphire lasers are important tools for producing solid-state laser radiation across visible and near-infrared bands. However, existing titanium-doped sapphire laser systems require high pumping power. They usually rely on expensive tabletop components, limiting them to lab environments.

A team of researchers has developed the first chip-scale titanium-doped sapphire laser – a breakthrough with applications ranging from atomic clocks to quantum computing and spectroscopic sensors. This is the world’s first titanium-doped sapphire (Ti:Sa) laser integrated with a chip-scale photonic circuit.

It offers the widest gain spectrum ever seen on a chip, paving the way for a host of new applications.

The accessibility of the laser is key. The Tang lab’s system has a threshold of about 6.5 milliwatts, while standard titanium-doped sapphire lasers had a threshold of more than 100 milliwatts. With some adjustments, they think they can lower it further to 1 milliwatt. Their method is also compatible with the gallium nitride optoelectronics family, which is commonly used in blue LEDs and lasers.

Scientists noted, “We demonstrate Ti:Sa lasing from 730 nm to 830 nm by tightly confining the pump and laser modes to a single microring resonator, reducing the laser threshold by orders of magnitude to 6.5 mW compared to free space Ti:Sa Lasers.”

“Because of the low-threshold, ready-to-use Ti:Sa laser operation is achieved by using a commercially available indium gallium nitride pump diode. Our prototype photonic-circuit-integrated Ti:Sa laser opens a reliable path for broadband tunable lasers in the next generation of active-passive-integrated visible photonics.”

Magazine reference:

  1. Wang, Y., Holguín-Lerma, JA, Vezzoli, M. et al. Photonic circuit-integrated titanium: sapphire laser. Wet. Photon. (2023). DOI: 10.1038/s41566-022-01144-2