Two-pulse lensless imaging with a broadband high-harmonic source

Abstract

We present a new approach to lensless imaging, which makes efficient use of the full spectrum of broadband light sources. Our approach is based on the principle of Fourier-transform spectroscopy. We use two time-delayed coherent light pulses as the source in a lensless imaging experiment, and record a set of images of the diffraction pattern as a function of time delay. In this way, the time-dependent signal detected on each camera pixel encodes a Fourier-transform spectrum of the spectral components incident on that specific pixel. By reconstructing the diffracted spectrum for all pixels, we can directly obtain spectrally resolved, quasi-monochromatic diffraction patterns for all spectral components in the source bandwidth. This approach works well for complex-shaped, ultra-broadband and even unknown spectra.