Abstract

Metasurfaces (MSs) are being investigated for a broad range of applications. However, they have found limited use in broadband dispersion engineering and the temporal shaping of short pulses. This is because conventional, singly-resonant MSs are inherently narrowband and exhibit a specific spectral phase profile dictated by the resonance dispersion [φ(ω) ∝ atan(γ(ω − Ω)) for a single Lorentzian resonance centered at Ω]. The first example of a broadband, specifically-engineered spectral phase concerned a linear profile (spectrally-constant group delay) utilized to delay broadband pulses without distortion [1] and applied to achromatic wavefront manipulation [2]. A wider class of important applications requires a quadratic phase profile, namely, dispersion compensation, chirped pulse amplification, and in general any application requiring control over the instantaneous frequency (chirp) and temporal duration of a broadband pulse through pulse chirping/de-chirping.

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