Adaptive optics-based wavefront-enhanced laser-induced fluorescence (WELIF) for improved analytical performance

Area of Science:

• Optical Physics
• Analytical Chemistry
• Biophotonics

Background:

• Laser-induced fluorescence (LIF) is a powerful analytical technique.
• Excitation laser wavefront aberrations limit LIF sensitivity and resolution.
• Adaptive optics (AO) systems offer potential for aberration correction.

Purpose of the Study:

• To develop and validate a novel optical approach, wavefront-enhanced LIF (WELIF), for enhancing fluorescence intensity.
• To demonstrate the effectiveness of WELIF in compensating for laser beam aberrations in real-time.
• To showcase the analytical applicability of WELIF using various solid and liquid samples, including extra virgin olive oil (EVOO).

Main Methods:

• Implementation of a closed-loop adaptive optics (AO) system comprising a deformable mirror (DM) and Shack-Hartmann wavefront sensor (SHWFS).
• Compensation for excitation laser wavefront aberrations in real-time.
• Measurement of fluorescence peak intensity enhancement using the WELIF technique on diverse samples.

Main Results:

• Significant improvement in fluorescence peak intensity observed across solid (bone, leaf, polymer) and liquid (EVOO) samples.
• Fluorescence peak intensities were enhanced by 20%–98% after aberration compensation (AC).
• Statistical validation using ROC curves (84% sensitivity AC vs. 82% BC) and PLSR (0.94 R^2 AC vs. 0.90 R^2 BC) confirmed WELIF's effectiveness.

Conclusions:

• The proposed WELIF method, utilizing AO, effectively compensates for laser wavefront aberrations, leading to substantial fluorescence intensity enhancement.
• WELIF demonstrates broad applicability for analyzing various sample types and improving analytical performance in LIF spectroscopy.
• The enhanced sensitivity and statistical robustness of WELIF offer significant advantages for quantitative and qualitative analysis.