All-reflective femtosecond optical pump-probe setup for transient grating spectroscopy

Area of Science:

• Ultrafast spectroscopy
• X-ray science
• Physical chemistry

Background:

• Four-wave mixing (FWM) is a powerful nonlinear optical technique.
• Extreme ultraviolet (EUV) and soft X-ray (SXR) spectral ranges offer unique insights into electronic and structural dynamics.
• Existing setups for EUV/SXR FWM experiments often involve complex transmission optics.

Purpose of the Study:

• To develop and validate a novel pump-probe optical setup for free electron laser (FEL)-based FWM experiments in the EUV/SXR range.
• To eliminate the need for transmission optics in the experimental design.
• To demonstrate the setup's reliability for studying material dynamics.

Main Methods:

• Development of a pump-probe optical layout specifically designed for FEL sources.
• Implementation of a transient grating (TG) technique.
• Testing the setup with both liquid and solid samples in transmission and reflection geometries.

Main Results:

• A functional pump-probe setup for EUV/SXR FWM experiments was successfully realized.
• The absence of transmission optics simplifies the experimental configuration.
• Reliable measurements were obtained on diverse sample types (liquid and solid) using the TG technique.

Conclusions:

• The developed setup provides a robust and versatile platform for advanced spectroscopic studies in the EUV/SXR regime.
• The design's reliance on reflection/transmission geometries without internal transmission optics enhances its applicability.
• This advancement facilitates deeper understanding of ultrafast dynamics in various materials using FELs.