Single-grating monochromator for extreme-ultraviolet ultrashort pulses

Area of Science:

• Physics
• Laser Science
• Spectroscopy

Background:

• High-order harmonic generation (HHG) produces extreme-ultraviolet (XUV) light.
• Efficiently isolating specific harmonic orders with minimal pulse distortion is crucial for applications.

Purpose of the Study:

• To develop and characterize a time-preserving monochromator for HHG pulses.
• To enable applications in ultrafast electron spectroscopy.

Main Methods:

• Utilizing a single grating in an off-plane mount within a time-preserving monochromator.
• Driving HHG with intense 30 fs near-infrared laser pulses.
• Measuring the pulse duration of monochromatized harmonic pulses.

Main Results:

• Separated XUV high-order-harmonic pulses with 1.6·10^7 photons/pulse at 32.5 eV.
• Achieved minimum temporal broadening and high efficiency due to the grating geometry.
• Measured pulse durations of 20–30 fs for the monochromatized pulses.
• Demonstrated tunable harmonic photon energy from 12 to 120 eV.

Conclusions:

• The off-plane mounted grating monochromator effectively isolates HHG orders with minimal temporal broadening.
• This technique is suitable for ultrafast electron spectroscopy, enhancing temporal resolution.
• The tunable energy range and high photon flux make it a versatile tool for XUV science.