Resonance Raman measurements of carotenoids using light emitting diodes

TL;DR

This paper introduces a compact, portable LED-based Raman spectrometer for non-invasive measurement of skin carotenoids, demonstrating high sensitivity, reproducibility, and potential for clinical applications.

Contribution

The development of a dual-LED excitation Raman instrument with advanced signal processing for reliable skin carotenoid detection is novel.

Findings

Sensitivity and reproducibility comparable to laser-based systems

Repeatability better than 10% in skin measurements

Effective compensation for detector drift

Abstract

We report on the development of a compact commercial instrument for measuring carotenoids in skin tissue. The instrument uses two light emitting diodes (LEDs) for dual-wavelength excitation and four photomultiplier tubes for multichannel detection. Bandpass filters are used to select the excitation and detection wavelengths. The f/1.3 optical system has high optical throughput and single photon sensitivity, both of which are crucial in LED-based Raman measurements. We employ a signal processing technique that compensates for detector drift and error. The sensitivity and reproducibility of the LED Raman instrument compares favorably to laser-based Raman spectrometers. This compact, portable instrument is used for non-invasive measurement of carotenoid molecules in human skin with a repeatability better than 10%.