Relativistic light synthesis of femtosecond sawtooth pulses

TL;DR

This paper demonstrates a novel method for generating femtosecond sawtooth pulses using relativistic oscillating mirrors, enabling efficient control of harmonic intensities without phase manipulation, and enhances terahertz pulse generation.

Contribution

It introduces a new relativistic light synthesis scheme for femtosecond sawtooth pulses that improves control and efficiency over existing methods.

Findings

Efficient control of harmonic intensities via plasma density gradient.

Generation of millijoule femtosecond sawtooth pulses.

Enhanced terahertz pulse generation by an order of magnitude.

Abstract

Formation of femtosecond sawtooth pulses by high harmonic generation from relativistic oscillating mirrors is studied. For oblique incidence of $p$-polarized laser pulse, one can efficiently control the intensity of the first few harmonics by modifying the plasma density gradient at the plasma-vacuum interface. With appropriate choice of the laser amplitude and incidence angle, the generated harmonics can form a millijoule femtosecond sawtooth pulse. The scheme does not rely on phase manipulation and/or pulse synchronization as in the state-of-art methods. It is also shown that such a sawtooth pulse can boost the generation of ultrashort terahertz pulses in laser-plasma interaction by one order of magnitude, as compared with that from the conventional two-color laser pulse.