Ever since the invention of the laser more than 50 years ago, scientists have strived to create an X-ray laser. In the same way that visible lasers can concentrate light energy far better than a light bulb, a directed beam of X-rays would have many useful applications in medicine, security screening and the sciences. The X-ray sources currently in use, though, are in essence the same X-ray light bulb source that Wilhelm Röntgen used in 1895. That’s because until recently X-ray lasers required ridiculously high power levels.
Making a practical, tabletop-scale, X-ray laser source requires taking a different approach that transforms a beam of light from a visible femtosecond laser into a beam of directed X-rays. The story behind how this happened is surprising and beautiful, highlighting how powerful our ability is to manipulate nature at a quantum level.
Along the way, we also learned to generate the shortest strobe light in existence — fast enough to capture the fastest attosecond electron dynamics in materials. We also learned how to achieve sub-wavelength spatial resolution at soft X-ray wavelengths for the first time. These new capabilities are already impacting nano and materials science, as well as showing promise for next-generation electronics, data and energy storage devices.