Energy scaling beyond the gas ionization threshold with divided-pulse nonlinear compression

Area of Science:

• Laser Physics
• Nonlinear Optics
• Fiber Optics

Background:

• Gas ionization in hollow-core fibers limits output pulse energy.
• Current methods struggle to scale pulse energy beyond these limitations.
• High pulse energy is crucial for many advanced laser applications.

Purpose of the Study:

• To demonstrate a method for scaling pulse energy beyond gas ionization limits in hollow-core fibers.
• To overcome the limitations of single-pulse energy delivery.
• To enable significant increases in laser pulse energy without increasing system size.

Main Methods:

• Utilizing divided-pulse nonlinear compression to split a single laser pulse into multiple lower-energy pulses.
• Propagating these divided pulses through a hollow-core fiber.
• Comparing the output pulse energy and ionization effects of single versus divided pulses.

Main Results:

• Single-pulse energy was limited to 2.7 mJ due to ionization at 4 mJ input.
• Dividing the pulse into four low-energy pulses eliminated ionization.
• Achieved a 2.5x increase in pulse energy, reaching 6.6 mJ at 10 mJ input.
• The new threshold for gas ionization was not reached, indicating potential for further scaling.

Conclusions:

• Divided-pulse nonlinear compression effectively bypasses gas ionization limitations in hollow-core fibers.
• This technique offers a scalable solution for achieving high pulse energies.
• The method is applicable to state-of-the-art laser systems for significant energy scaling without size increase.