Polarization purity for active stabilization of diode laser injection lock

Area of Science:

• Applied Physics
• Laser Technology
• Quantum Optics

Background:

• Diode laser injection locking amplifies light but is sensitive to current and temperature fluctuations.
• Active stabilization is crucial for maintaining injection lock quality and performance.
• Existing methods often require complex setups or are limited in bandwidth.

Purpose of the Study:

• To develop a robust active stabilization technique for diode laser injection locks.
• To utilize the polarization extinction ratio (PER) as a feedback signal for stabilization.
• To demonstrate the effectiveness of PER-based stabilization at 399 nm.

Main Methods:

• Monitoring the diode laser's polarization extinction ratio (PER) during injection locking.
• Using the PER as an error signal for a proportional-integral-derivative (PID) servo controller.
• Implementing the stabilization system without additional optical components beyond a standard isolator.

Main Results:

• The PER significantly increases upon successful injection locking, serving as a reliable indicator of lock quality.
• Robust active stabilization of the injection lock was achieved using the PER feedback signal.
• The technique demonstrated effective stabilization at 399 nm, a wavelength where injection locking is typically less stable.
• The PER-based feedback allowed for a large feedback bandwidth compatible with standard controllers.

Conclusions:

• The polarization extinction ratio (PER) is a viable and effective parameter for active stabilization of diode laser injection locks.
• PER-based stabilization offers a simple, robust, and high-bandwidth solution, particularly for challenging wavelengths like 399 nm.
• This technique enhances the reliability and performance of injection-locked diode lasers for various applications.