Power and noise dynamics in SESAM modelocked GHz-class SWIR solid-state lasers

Area of Science:

• Laser Physics
• Optoelectronics
• Materials Science

Background:

• Gigahertz (GHz)-class femtosecond lasers in the short-wave infrared (SWIR) are critical for advanced spectroscopy and nonlinear optics.
• Semiconductor saturable absorber mirror (SESAM) mode-locking is a proven method for stable GHz laser generation.
• Understanding SESAM and cavity parameter effects in SWIR lasers is essential for performance optimization.

Purpose of the Study:

• Investigate power and noise dynamics in a 1-GHz SESAM mode-locked Cr:ZnS laser.
• Determine the relationship between SESAM/cavity parameters and relaxation oscillations.
• Establish a framework for optimizing SWIR lasers for specific applications.

Main Methods:

• Experimental investigation of a 1-GHz SESAM mode-locked Cr:ZnS laser.
• Engineering SESAM modulation depth to study power-noise trade-offs.
• Numerical simulations to support experimental findings.

Main Results:

• A direct link between SESAM/cavity parameters and relaxation oscillations was identified.
• Higher SESAM modulation depth yielded lower noise (0.05% RIN, 62 fs jitter) at 93 mW average power.
• Lower SESAM modulation depth allowed power scaling to 0.8 W but increased noise (0.94% RIN, 187 fs jitter).

Conclusions:

• SESAM modulation depth fundamentally governs the power-noise performance of GHz SWIR lasers.
• Results provide a practical guide for tailoring SWIR laser performance.
• Optimized SESAM and cavity parameters are key for high-precision spectroscopy and nonlinear conversion.