Coherent combination of ultrashort pulse beams using two diffractive optics

Area of Science:

• Optics and Photonics
• Ultrafast Lasers
• Diffractive Optics

Background:

• Combining multiple femtosecond laser pulses is crucial for high-intensity applications.
• Existing methods face challenges with pulse distortion and scalability.
• Minimizing pulse front tilt and dispersion is essential for coherent beam combination.

Purpose of the Study:

• To present a novel coherent beam combiner using diffractive optics.
• To demonstrate the cancellation of pulse front tilt and minimization of uncorrected dispersions.
• To analyze the scalability and efficiency of the proposed beam combining technique.

Main Methods:

• Development of a novel coherent beam combiner utilizing a pair of diffractive optics.
• Numerical modeling and experimental validation of the beam combiner with four femtosecond pulse beams.
• Analytical scaling of the system to combine a larger number of beams.

Main Results:

• Experimental demonstration of combining four 120 fs pulses without pulse width degradation.
• Numerical modeling confirmed the effectiveness of the diffractive optic pair in correcting pulse front tilt.
• Analytical results indicate minimal combining loss (few percent) for approximately 200 beams with 130 fs pulses.

Conclusions:

• The presented diffractive optic beam combiner is effective for combining large numbers of femtosecond pulses.
• The system successfully mitigates pulse front tilt and minimizes dispersion-induced losses.
• This technology offers a scalable solution for high-power ultrafast laser systems.