Attosecond pulses are extremely short bursts of light that last for a duration of one quintillionth of a second, or 10 to the power of 18 seconds. They are used in attosecond physics, a branch of physics that deals with light-matter interaction and aims to unravel dynamical processes in matter with unprecedented time resolution. Attosecond science mainly employs pump-probe spectroscopic methods to investigate the physical process of interest. The generation of attosecond pulses requires two key elements: bandwidth and central wavelength of the electromagnetic wave. Attosecond pulses are generated by high-order harmonic generation (HHG) in a laser field.
Attosecond pulses have many applications in physics, including the ability to create and manipulate extreme ultraviolet (XUV) and X-ray pulses, which are vital for imaging ultrafast processes at the atomic and molecular scale. With these attosecond pulses, scientists can "freeze" the motion of electrons within atoms and molecules, providing a real-time view of electron movement during chemical reactions. Attosecond pulses also allow scientists to observe the quantum mechanical nature of electrons and the intricate dance they perform during chemical reactions.
Recent advances in photonics have made it possible to generate attosecond pulses at a repetition rate of 100 kHz, which enables new types of experiments in attosecond science. In many attosecond experiments, it is beneficial to have isolated attosecond pulses instead of a train of multiple attosecond pulses. To enable the efficient generation of isolated attosecond pulses, the laser pulses driving the generation process should have pulse durations as close as possible to a single cycle of light. These high flux isolated attosecond pulses open the door for attosecond pump-probe spectroscopy studies at a repetition rate 1 or 2 orders of magnitude above current implementations.
