Active intensity noise suppression for a broadband mid-infrared laser source

Area of Science:

• Laser physics
• Spectroscopy
• Optical engineering

Background:

• Relative intensity noise (RIN) is a significant limitation in laser-based spectroscopic techniques.
• Coherent mid-infrared (MIR) light sources are crucial for various spectroscopic applications.

Purpose of the Study:

• To develop and evaluate an active RIN suppression scheme for a MIR light source.
• To compare different stabilization concepts for noise reduction.

Main Methods:

• Intra-pulse difference frequency generation (DFG) was used to generate the MIR light.
• An acousto-optic modulator controlled the intensity of the driving near-infrared (NIR) pulse train.
• Error signals were generated using the wings of the NIR spectrum for feedback stabilization.

Main Results:

• A RIN suppression of up to a factor of 20 was achieved for the MIR pulse train.
• Suppression was effective in the frequency band between 1 Hz and 100 kHz.
• The total integrated RIN was reduced to 0.07%.

Conclusions:

• The proposed active RIN suppression scheme effectively reduces noise in MIR light sources.
• This advancement can significantly improve the performance of laser-based spectroscopic methods.
• The developed technique offers a practical solution for enhancing MIR light source stability.