Simple high-coherence rapidly tunable external-cavity diode laser

Area of Science:

• Optics and Photonics
• Laser Physics
• High-Speed Electronics

Background:

• External-cavity diode lasers (ECDLs) are crucial for tunable laser sources.
• Achieving high-speed and high-coherence tuning simultaneously remains a challenge.
• Existing methods often compromise spectral purity for tuning speed.

Purpose of the Study:

• To present a novel electro-optically activated external-cavity diode laser.
• To demonstrate high-speed, high-coherence frequency tuning capabilities.
• To introduce a new method for characterizing phase coherence during rapid tuning.

Main Methods:

• Design and construction of a simple electro-optically activated ECDL.
• High-speed frequency tuning measurements up to 23 GHz/µs.
• Coherence characterization using self-heterodyne, cross-correlation techniques.
• Analysis of laser linewidth and chirp properties.

Main Results:

• Demonstrated gigahertz frequency tuning ranges.
• Achieved tuning speeds as high as 23 GHz/µs.
• Observed transform-limited laser linewidth in extended observation windows (~100 µs).
• Confirmed transform-limited frequency chirps during high-speed operation.

Conclusions:

• The developed ECDL offers a unique combination of speed and coherence.
• The laser is suitable for applications requiring rapid, spectrally pure frequency sweeps.
• The novel coherence diagnostic effectively characterizes phase coherence in dynamic laser systems.