"Photophony" Natural Recordings by Native Speakers
Photophony (from Greek φῶς, phos, "light" and φωνή, phōnē, "sound") is a phenomenon in physics where a light (photons) striking certain materials can generate sound waves.
Photons are elementary particles that represent the smallest units of light. They are massless particles that travel at the speed of light and have zero charge. Photons have both wave-like and particle-like properties.
A photoplethysmogram (PPG) is a non-invasive measurement of the changes in blood volume in the skin, which occur with every heartbeat. It is used to monitor the physiological activity of the cardiovascular system, particularly the heart rate and peripheral circulation.The PPG signal is typically measured using a light emitter and detector placed on the skin, usually on the finger, earlobe, or forehead. The light is absorbed by the blood in the skin, and the changes in absorption that occur with each heartbeat are detected by the photodetector, producing a signal that is expressed in amplitude and time.A photoplethysmogram can be used for a variety of purposes, including:1. Heart rate monitoring: PPG can be used to measure heart rate and rhythm, providing real-time feedback on cardiovascular activity.2. Blood oxygen saturation: PPG can be used to estimate blood oxygen saturation levels, which can be useful in patients with respiratory or cardiovascular conditions.3. Blood pressure monitoring: PPG can be used to estimate blood pressure levels, particularly in situations where traditional blood pressure monitoring methods are not available.4. Cardiac function monitoring: PPG can be used to assess cardiac function, including stroke volume and cardiac output.5. Monitoring of patients with cardiovascular disease: PPG can be used to monitor patients with cardiovascular disease, including those with heart failure, atrial fibrillation, or other conditions that affect cardiac function.Overall, photoplethysmography is a valuable tool for healthcare professionals to monitor the cardiovascular system and provide early detection and treatment of cardiovascular disease.