Femtosecond to Attosecond Optics

We continue to observe strong progress moving from femtosecond to attosecond optics. Attosecond pulses are now available in many different labs with additional gating techniques which somewhat relax the requirements for the pulse duration of the intense infrared laser pulses. The pulse repetition rate still sets a limit on the signal-to-noise ratio for attosecond pump-probe measurements, and therefore, other streaking techniques have resulted in time-resolved measurements with sub-10-attosecond accuracy. Recent improvements on high-power ultrafast diode-pumped solid-state and fiber lasers will offer alternative sources for megahertz attosecond pulse generation. First proof-of-principle experiments have been demonstrated.