Ultrafast Laser Technology and Spectroscopy

Ultrafast laser technology and spectroscopy involves the use of femtosecond (10−15 s) laser and other (particle) sources to study the properties of matter. The extremely short pulse duration allows one to create, detect and study very short-lived transient chemical reaction intermediates and transition states. Ultrafast lasers can also be used to produce laser pulses with enormous peak powers and power densities. This leads to applications such as laser machining and ablation, generation of electromagnetic radiation at unusual wavelengths (such as millimeter waves and X-rays), and multiphoton imaging. The difficulty in applying femtosecond laser pulses is that the broad frequency spectrum can lead to temporal broadening of the pulse on propagation through the experimental set-up. In this article, we describe the generation and amplification of femtosecond laser pulses and the various techniques that have been developed to characterize and manipulate the pulses.