InGaN-diode-pumped AlGaInP VECSEL with sub-kHz linewidth at 689 nm

Area of Science:

• Optics and Photonics
• Quantum Technology

Background:

• Vertical-cavity surface-emitting lasers (VECSELs) are crucial for various applications.
• Developing compact, stable, and tunable laser sources is essential for advancing quantum technologies.

Purpose of the Study:

• To design, grow, and characterize an AlGaInP-based VECSEL.
• To achieve stable, single-mode emission around 689 nm using optical pumping.
• To assess the suitability of this VECSEL for quantum applications, specifically those involving strontium atoms.

Main Methods:

• Optical pumping of an AlGaInP VECSEL using a blue InGaN diode laser.
• Characterization of output power, tunability, and mode properties (TEM00, single longitudinal mode).
• Intensity stabilization of the pump diode and frequency stabilization of the VECSEL resonator using the Pound-Drever-Hall technique.

Main Results:

• Achieved up to 140 mW output power in a circularly-symmetric single transverse mode.
• Demonstrated tunability from 683 to 693 nm.
• Measured sub-kHz linewidth and relative intensity noise (RIN) below -130 dBc/Hz above 100 kHz.

Conclusions:

• The developed VECSEL is a compact and stable laser source.
• Its performance characteristics are well-suited for applications in quantum technologies.
• Specifically recommended for laser-cooled and trapped strontium atom experiments.