Applications of ultrashort laser pulses

摘要

An impressive range of ultrashort-pulse lasers has been developed, based on the general techniques of active and passive modelocking, which date back to the mid-1960s (Siegman 1986, Keller this book). More recent noteworthy advances have resulted from the development in the 1980s of high quality titanium-doped sapphire as a practical broad-bandwidth laser crystal (Moulton 1982, 1986) and the subsequent demonstration of self- (or Kerr-lens) modelocking (Spence et al. 1990, 1991) which has afforded picosecond/femtosecond-pulse generation with unrestricted tunability for such a gain medium. When complemented by chirped-pulse amplification (Strickland and Mourou 1985, Keller this book), the modern "user-kit" now provides clear access to robust and versatile ultrashort-pulse sources that provide peak optical powers in the megawatt to petawatt regimes. With appropriate frequency up/down conversion procedures, spectral access can extend from X-rays to T-rays (terahertz radiation) with relative ease. Additionally, the established characterisation techniques of autocorrelation and optical/microwave spectral analyses have been enhanced recently by schemes such as frequency-resolved optical gating (Delong et al. 1994a,b) so that the phase-related features of these ultrashort pulses can be monitored in a quantitative manner. Thus, a range of well-characterised ultrashort-pulse sources is currently available to several broadly-based user communities.