Synchronous acousto-optic tuning of free-space external-cavity lasers

Mechanically tuned external-cavity lasers in which the cavity and the mode filter are tuned synchronously are well known and commercially available. The synchronicity allows phase-continuous tuning to be obtained. Acousto-optic tuning has potential advantages in terms of speed, stability, and precision, but a method for synchronous tuning is required. We propose such a method and describe its experimental verification.