Two-dimensional electronic spectroscopy in the ultraviolet by a birefringent delay line

Area of Science:

• Physical Chemistry
• Spectroscopy
• Ultrafast Dynamics

Background:

• Two-dimensional electronic spectroscopy (2DES) is a powerful technique for studying ultrafast molecular dynamics.
• Extending 2DES into the ultraviolet (UV) spectral range offers new possibilities for probing electronic transitions in a wide range of molecules.
• Achieving stable, phase-locked UV pulses is crucial for high-resolution 2DES measurements.

Purpose of the Study:

• To introduce a novel 2D electronic spectroscopy setup operating in the UV spectral range.
• To demonstrate a method for generating interferometrically phase-locked few-optical-cycle UV pulse pairs.
• To validate the setup by acquiring 2DUV maps of a pyrene solution.

Main Methods:

• A partially collinear pump-probe geometry was employed for the 2D electronic spectroscopy setup.
• Phase-locked visible pulse pairs were generated using a passive birefringent interferometer.
• Nonlinear phase transfer via sum-frequency generation with narrowband infrared pulses was used to create UV pulses.

Main Results:

• A stable pair of 16-fs, 330-nm UV pulses was successfully generated.
• The pulse delay stability was demonstrated to be better than λ/450.
• Two-dimensional ultraviolet (2DUV) maps of pyrene solution were successfully acquired using both UV and visible probes.

Conclusions:

• The developed 2D electronic spectroscopy setup enables high-resolution measurements in the UV spectral range.
• The method for generating phase-locked UV pulses is robust and provides excellent stability.
• This technique opens new avenues for investigating excited-state dynamics of molecules in the UV region.