Long-term stabilization of high power optical parametric chirped-pulse amplifiers

Area of Science:

• Ultrafast optics and laser science
• Nonlinear optics and photonics
• High-power laser systems

Background:

• Long-term stability of optical parametric chirped-pulse amplifiers (OPCPAs) is compromised by thermal path length drifts.
• These drifts critically affect the temporal overlap between the pump and signal pulses, limiting amplifier performance.
• Precise temporal synchronization is essential for generating ultrashort laser pulses with high energy and broad spectral bandwidth.

Purpose of the Study:

• To investigate and demonstrate methods for enhancing the long-term stability of kilowatt-pumped burst amplifiers.
• To achieve active and passive temporal synchronization between pump and signal pulses with femtosecond-level precision.
• To enable the generation of ultrabroadband pulses with durations supporting sub-7 femtosecond pulse durations.

Main Methods:

• Development and characterization of a kilowatt-pumped burst amplifier system.
• Implementation of active temporal overlap control using a balanced optical cross-correlator.
• Proposal and testing of passive pump-to-signal stabilization utilizing white-light continuum generation.

Main Results:

• The burst amplifier delivers broadband 1.4 mJ pulses with spectral bandwidth supporting sub-7 fs pulse durations.
• Active synchronization via optical cross-correlation achieved a residual pump-to-signal jitter of (46 ± 2) fs rms.
• Passive stabilization using white-light continuum generation demonstrated an intrinsic jitter of (7.0 ± 0.5) fs rms.

Conclusions:

• Both active and passive stabilization techniques significantly improve pump-to-signal synchronization in high-power burst amplifiers.
• Passive stabilization offers superior timing jitter performance, paving the way for highly stable ultrashort pulse generation.
• The demonstrated techniques address key limitations in OPCPAs, enabling advancements in ultrafast laser technology.