CEP-controlled supercontinuum generation during filamentation with mid-infrared laser pulse

Area of Science:

• Nonlinear Optics
• Ultrafast Laser Physics

Background:

• Carrier-envelope phase (CEP) stabilization is crucial for precise control of ultrashort laser pulses.
• Supercontinuum generation in optical materials is a key phenomenon in ultrafast optics.

Purpose of the Study:

• To investigate the influence of CEP on supercontinuum generation in fused silica.
• To determine the optimal conditions for observing CEP-controlled supercontinuum generation.

Main Methods:

• Experimental generation of supercontinuum using CEP-stabilized mid-infrared laser pulses.
• Numerical simulations to model the underlying physical processes.
• Varying laser focus position relative to the fused silica surface.

Main Results:

• CEP-controlled supercontinuum generation observed within a narrow focal range near the fused silica exit surface.
• The CEP effect diminishes with increasing focal distance from the surface.
• Numerical simulations confirm CEP's role originates from tunneling ionization but is observable only when self-phase modulation and self-steepening dominate.

Conclusions:

• The spatial confinement of the laser focus is critical for observing CEP effects in supercontinuum generation.
• Supercontinuum generation dynamics, specifically self-phase modulation and self-steepening, are essential for manifesting CEP control.
• Excessive electron generation can obscure the observable CEP effect.