What Does HHG Stand For?

HHG stands for High Order Harmonic Generation

High Order Harmonic Generation (HHG) is a nonlinear optical process in which intense laser fields interact with atoms or molecules to produce high-frequency photons, typically in the ultraviolet or extreme ultraviolet range. This phenomenon occurs when a laser light's electric field distorts the potential energy landscape of an atom, causing it to emit harmonics at integer multiples of the fundamental laser frequency. HHG is a crucial technique in attosecond science, enabling the generation of ultrashort light pulses for probing dynamic processes in physics, chemistry, and biology.