Narrowband diode laser pump module for pumping alkali vapors.

Area of Science:

• Atomic, Molecular, and Optical Physics
• Laser Engineering
• Materials Science

Background:

• Diode laser stacks are crucial for Diode Pumped Alkali Lasers (DPALs).
• Broadband diode lasers exhibit wide line widths (e.g., 3 THz), limiting their efficiency in DPALs.
• Precise frequency control is essential for resonant pumping of alkali atoms.

Purpose of the Study:

• To develop a method for line narrowing and frequency-locking a diode laser stack.
• To adapt the narrowed diode laser stack as an efficient pump module for DPALs.
• To achieve a narrow spectral line width for improved laser performance.

Main Methods:

• Utilized a 600 W antireflection coated diode laser stack in an external cavity configuration.
• Introduced a narrowband polarization filter based on the magneto-optical Faraday effect into the external cavity.
• The filter selectively transmitted frequencies resonant with the 6²S_1/2 → 6²P_3/2 transition of Cesium (Cs) atoms.

Main Results:

• Successfully narrowed the diode laser stack line width from 3 THz to 10 GHz.
• The line-narrowed pump module achieved an output power of 518 Watts.
• This represents 80% of the power generated by the original broadband diode laser stack.

Conclusions:

• The magneto-optical Faraday effect filter effectively narrows the diode laser stack's spectral line width.
• The developed pump module demonstrates high efficiency and suitability for DPAL applications.
• This method offers a viable solution for enhancing DPAL performance through precise laser frequency control.