Attosecond science involves the study of ultrafast processes in matter using light pulses shorter than 100 attoseconds. These pulses, first produced in 2001, enable the observation of electron dynamics on timescales of attoseconds, such as photoionization delays and molecular dissociation. The generation of attosecond pulses relies on high harmonic generation (HHG), where an intense laser field causes an electron to be ejected, accelerated, and recombine with the ion, emitting a photon. The pulse duration is determined by the laser wavelength and intensity, with shorter wavelengths allowing for shorter pulses. The HHG process is sensitive to the electron wavefunction and can be used to generate isolated attosecond pulses through techniques like carrier-envelope phase control. Attosecond pulses are measured using methods such as RABBIT (Reconstruction of attosecond beating by interference of two-photon transitions) and streaking, which determine the temporal characteristics of the pulses. These techniques involve measuring the photoelectron energy spectrum and modulating it with an infrared field to extract phase and amplitude information. In situ measurements, such as petahertz optical oscilloscopes, allow for direct observation of the pulse shape and timing within the medium where the pulses are generated. Applications of attosecond science include measuring photoionization delays, where the time it takes to remove an electron from an atom or surface is determined. For example, 2s electrons in neon are removed 20 attoseconds after 2p electrons. Similarly, in argon, 3s electrons are removed before 3p electrons. Transient absorption spectroscopy using attosecond pulses allows for the study of molecular dynamics, such as the dissociation of dibromoethane, by observing changes in absorption as a function of time delay. The field of attosecond science has advanced significantly since its inception, with applications in understanding fundamental physical processes and molecular dynamics. Future developments are expected to expand the use of attosecond technology in various scientific domains.Attosecond science involves the study of ultrafast processes in matter using light pulses shorter than 100 attoseconds. These pulses, first produced in 2001, enable the observation of electron dynamics on timescales of attoseconds, such as photoionization delays and molecular dissociation. The generation of attosecond pulses relies on high harmonic generation (HHG), where an intense laser field causes an electron to be ejected, accelerated, and recombine with the ion, emitting a photon. The pulse duration is determined by the laser wavelength and intensity, with shorter wavelengths allowing for shorter pulses. The HHG process is sensitive to the electron wavefunction and can be used to generate isolated attosecond pulses through techniques like carrier-envelope phase control. Attosecond pulses are measured using methods such as RABBIT (Reconstruction of attosecond beating by interference of two-photon transitions) and streaking, which determine the temporal characteristics of the pulses. These techniques involve measuring the photoelectron energy spectrum and modulating it with an infrared field to extract phase and amplitude information. In situ measurements, such as petahertz optical oscilloscopes, allow for direct observation of the pulse shape and timing within the medium where the pulses are generated. Applications of attosecond science include measuring photoionization delays, where the time it takes to remove an electron from an atom or surface is determined. For example, 2s electrons in neon are removed 20 attoseconds after 2p electrons. Similarly, in argon, 3s electrons are removed before 3p electrons. Transient absorption spectroscopy using attosecond pulses allows for the study of molecular dynamics, such as the dissociation of dibromoethane, by observing changes in absorption as a function of time delay. The field of attosecond science has advanced significantly since its inception, with applications in understanding fundamental physical processes and molecular dynamics. Future developments are expected to expand the use of attosecond technology in various scientific domains.