Facile Optical Interrogation for Random Pulse Measurement: Characterization and Analysis of PPG Waveforms Using a Reflection-Based Sensor.

A compact reflection-mode optical sensor was developed and evaluated for noninvasive pulse waveform measurement using photoplethysmography (PPG). The sensor integrates an infrared light-emitting diode and photodetector, enabling real-time acquisition of PPG signals from subjects with diverse ages and health conditions. Despite a limited sample size, the device demonstrated reliable detection of physiologically relevant differences in pulse waveforms. The average systolic amplitude was 105.06 mV, with a mean pulse width of 0.14 s and an augmentation index of 0.19. Notably, subjects with identified health issues showed a trend toward higher augmentation index values and reduced compliance in pulse waveform morphology, consistent with diminished vascular elasticity. These findings highlight the potential of the proposed approach for early cardiovascular screening and personalized health monitoring. Future work will focus on validating the sensor in larger cohorts and enhancing robustness for real-world applications.