ABSTRACT
Self-phase modulation (SPM)-induced spectral broadening has been well known since 1968 [1]. Signicant spectral broadening from 400 nm to 700 nm in borosilicate glasses was rst reported by Alfano and Shapiro in 1970 [2]. It was achieved using picosecond pulses from a frequencydoubled Nd glass laser. The white light continuum was studied in liquids using picosecond and femtosecond pulses from dye lasers in subsequent years [3, 4] and was used in time-resolved spectroscopy. SPM was identied as the key physical mechanism. Gersten from the Alfano group rst used Supercontinuum generation to describe the process in 1980 [5].
