Abstract: A physiological monitoring system may use photoacoustic sensing to determine one or more physiological parameters of a subject. The photoacoustic system may use two light sources (e.g., a high power pulsed laser diode and a continuous wave laser diode) to generate acoustic pressure signals in a subject. One or more light sources (e.g., the high powered pulsed laser diode) may provide a high signal-to-noise ratio. The high signal-to-noise ratio signals may provide high sensitivity for physiological measurements (e.g., cardiac output and temperature measurements). The photoacoustic system may use high powered light sources in combination with other light sources to improve physiological measurements.

Abstract: Methods and systems are provided that include sampling a light intensity signal at different frequencies based on the waveform of the signal to produce a more accurate digitized signal. The light intensity signal is an analog signal proportional to the intensity of light received at a detector of a pulse oximetry system. In one embodiment, the signal may be sampled exponentially during pulse width periods, such that the end of the pulse width periods where the signal reaches a maximum amplitude may be sampled more frequently. The signal may also be exponentially sampled or oversampled during periods when the signal is expected to near maximum amplitude. Further, the signal may be sampled less frequently during low amplitude periods of the signal, and during dark periods, such that processing power may be conserved.

Abstract: A pulse oximeter sensor comprising an emitter and a detector disposed on a substrate layer with a thinned portion between the emitter and the detector. A partially transparent covering layer covers the substrate layer and comprises a corresponding thinned portion. The thinned portions attenuate light shunted via the substrate layer and the partially transparent covering layer from the emitter to the detector, and may be configured such that less than 10% of the light detectable by the detector is shunted light.