A Single-Shot Technique for Measuring Broadband Two-Photon Absorption Spectra in Solution

Area of Science:

• Nonlinear Optics
• Spectroscopy
• Materials Science

Background:

• Accurate two-photon absorption (2PA) spectra are crucial for applications like two-photon fluorescence imaging, photodynamic therapy, and 3D data storage.
• Traditional broadband pump-probe spectroscopy, while providing detailed spectra, can be complicated by cross-phase modulation and probe dispersion artifacts.

Purpose of the Study:

• To introduce a novel single-shot broadband two-photon absorption (BB-2PA) spectroscopy method.
• To overcome limitations of existing scanning pump-probe techniques, including artifacts and measurement time.

Main Methods:

• Development of a single-shot spectroscopy approach utilizing counterpropagating beams.
• Elimination of time delay scanning between pump and probe pulses.
• Demonstration using coumarin 153 (C153) as a reference in three solvents with a Yb:KGW laser.

Main Results:

• The single-shot method effectively eliminates cross-phase modulation artifacts.
• Measurements are significantly faster due to the avoidance of time delay scanning.
• Accurate and reliable 2PA cross sections were obtained, comparable or superior to existing methods.

Conclusions:

• The single-shot BB-2PA spectroscopy offers a more robust and efficient alternative to scanning pump-probe methods.
• This technique provides more reliable and easily obtainable 2PA cross sections.
• It presents significant advantages over single-wavelength techniques like z-scan and two-photon fluorescence measurements.