Shot-noise-limited laser power stabilization with a high-power photodiode array

Area of Science:

• Laser Physics
• Optical Engineering
• Gravitational Wave Detection

Background:

• High-power lasers are crucial for sensitive scientific instruments.
• The Advanced Laser Interferometer Gravitational-Wave Observatory (LIGO) requires exceptional laser power stability.
• Previous methods struggled to meet the stringent noise requirements for gravitational wave detection.

Purpose of the Study:

• To stabilize the output power of a continuous-wave Nd:YAG laser.
• To achieve power stability meeting the demands of the Advanced LIGO detector.
• To demonstrate a novel feedback loop for laser power stabilization.

Main Methods:

• Utilized a direct current (dc)-coupled feedback loop.
• Incorporated a low-noise multiphotodiode detector.
• Employed an electro-optic amplitude modulator for power control.
• Operated within the 1 Hz to 1 kHz frequency band.

Main Results:

• Achieved an independently measured relative power noise of 2.4 x 10(-9) Hz(-1/2) at 10 Hz.
• This represents a significant advancement in laser power stabilization.
• The achieved stability meets the requirements for Advanced LIGO.

Conclusions:

• The developed feedback loop effectively stabilizes Nd:YAG laser power.
• This stabilization technique is critical for enhancing gravitational wave detection sensitivity.
• The results pave the way for more precise astrophysical observations.