Enhanced two-photon fluorescence excitation by resonant grating waveguide structures.

Area of Science:

• Spectroscopy
• Optics
• Materials Science

Background:

• Two-photon fluorescence (TPF) spectroscopy is a valuable technique for various applications.
• Current TPF methods often require highly focused laser excitation, limiting sensitivity and applicability.
• There is a need for enhanced TPF detection methods that are more accessible and sensitive.

Purpose of the Study:

• To present enhanced two-photon fluorescence (TPF) spectroscopy using novel resonant polymeric grating waveguide structures (GWSs).
• To demonstrate the capability of GWSs to enhance TPF signals without requiring highly focused laser excitation.
• To quantify the improvement in TPF detection achieved with resonant GWSs.

Main Methods:

• Fabrication of high-finesse resonant polymeric grating waveguide structures (GWSs).
• Comparison of TPF signals from tetramethylrhodamine (TMR) placed on a GWS versus a standard glass substrate.
• Measurement of TPF intensity under resonant conditions at the GWS surface.

Main Results:

• Resonant GWSs provide significant field enhancement at their surface.
• TPF detection using resonant GWSs showed a marked improvement compared to a glass substrate.
• An enhancement factor of up to 10 in TPF detection was achieved with the resonant GWSs.

Conclusions:

• Novel resonant polymeric GWSs offer a powerful platform for enhancing TPF spectroscopy.
• The GWS approach enables sensitive TPF detection without the need for highly focused laser excitation.
• This technology has the potential to significantly advance TPF-based analytical and imaging techniques.