The generation of light pulses with attosecond (10−18seconds) duration is studied using laser drivers operating in the mid‐infrared region. This paper first examines the fundamental principles of attosecond formation by Fourier synthesis of a high harmonic comb. Experimental demonstration of the extension of the harmonic cutoff is shown using a 2 micron driver. Then, the crucial spectral phase properties, responsible for the pulse structure on the attosecond time scale, are measured with an all‐optical technique using a mix of the fundamental pulse with its second harmonic. The expected 1/λ scaling is verified, which demonstrates a practical way towards pulses approaching the atomic unit of time (24 as).

This content is only available via PDF.
You do not currently have access to this content.