Extreme-ultraviolet spectral compression by four-wave mixing

Extreme-ultraviolet (XUV) sources including high-harmonic generation (HHG), free-electron lasers (FELs), soft-X-ray and laser-driven plasmas are widely used for applications ranging from femtochemistry attosecond science to coherent diffractive imaging EUV (or XUV) lithography. The bandwidth of the XUV light emitted by these reflects process used. Whereas lasers1 seeded FELs2 typically has a relatively narrow bandwidth, plasma HHG often emit broadband pulses3. Since characteristic properties given source impose limitations on applications, techniques enabling modification highly desirable. Here we introduce concept efficient spectral compression four-wave mixing (FWM), exploiting phase-matching scheme based closely-spaced resonances. We demonstrate radiation in 145–130 nm wavelength range into narrow-bandwidth pulse at 100.3 presence near-infrared (NIR) krypton gas jet. Our provides new possibilities tailoring beams. Through dense jet pulse, between 145 130 wavelengths is demonstrated.