Single-shot achromatic imaging for broadband soft x-ray pulses

Abstract

An achromatic soft x-ray imaging system based on a transmission microscope equipped with a pair of Wolter mirrors was constructed. The two Wolter mirrors for the condenser and the objective were fabricated precisely by using an electroforming replication process. The samples were illuminated by broadband high harmonic pulses in the wavelength range of 26 nm to 35 nm via the condenser mirror, and transmission bright-field images without chromatic aberration were formed by the objective mirror. A single-shot image illuminated by a femtosecond laser pulse was recorded at a spatial resolution of about 200 nm. The fundamental capability of the microscope to realize broadband images without chromatic aberration will lead to the development of soft x-ray microscopes with extremely short illumination pulses on the order of attoseconds.