Separation of high order harmonics with fluoride windows

Area of Science:

• Ultrafast science
• Nonlinear optics
• Molecular spectroscopy

Background:

• High harmonic generation (HHG) produces ultrashort pulses of extreme ultraviolet (XUV) light.
• Separating the lower harmonic orders from HHG is crucial for many applications.
• Preserving the femtosecond pulse duration during separation is a significant challenge.

Purpose of the Study:

• To investigate the temporal separation of lower harmonic orders from HHG using fluoride windows.
• To assess the preservation of femtosecond pulse duration during this separation process.
• To apply this technique for resolving ultrafast molecular dynamics.

Main Methods:

• Numerical calculations of pulse propagation through MgF2, CaF2, and LiF windows.
• Simulation of the third, fifth, and seventh harmonics of 800 nm fundamental light.
• Implementation of the fluoride window technique in a pump/probe experimental setup.

Main Results:

• Fluoride windows efficiently separate lower harmonic orders from HHG.
• Femtosecond pulse durations are maintained after propagation through the fluoride windows.
• Ultrafast dynamics of the ethylene molecule were successfully resolved using this method.

Conclusions:

• Propagation through fluoride windows offers an effective and inexpensive method for temporal separation of HHG lower orders.
• This technique enables the study of femtosecond molecular dynamics with high temporal resolution.
• The findings have implications for advanced spectroscopy and attosecond science.