A femtosecond is equal to 1000 attoseconds, or 1/1000 picosecond. Lasers with ultraviolet and infrared wavelengths and nanosecond to femtosecond pulse widths have been used. Advances in femtosecond methods are crucial to the understanding of ultrafast phenomena in nature. Visible and infrared femtosecond lasers were also applied for lithography. This phenomenon can be used to investigate peptide conformational dynamics with femtosecond absorption spectroscopy. An attosecond is equal to 1000 zeptoseconds, or of a femtosecond. Even high-lying bands can be effective as femtosecond two-photon experiments have shown. The formula 10 case is used in Femtosecond pulse shaping. In 2006 they found a new use in femtosecond pulse shaping. Fully fibre integrated femtosecond sources have since been developed and demonstrated. The word "femtosecond" is formed by the SI prefix "femto" and the SI unit "second". These are the brightest X-ray sources currently available; with the X-rays coming in femtosecond bursts. Until the advent of femtosecond methods, many of the mechanism of such processes were unknown.