Laser microphone

In a standard microphone, sound waves move a diaphragm and these movements are translated into electricity. But the diaphragm's mass and resilience can easily reduce its sensitivity and add distortion to any finished recording.David Schwartz, an inventor based in California, US, thinks a much more sensitive microphone could be built using a diaphragm made from a continuous microscopic flow of water particles and a laser that senses the way this flow responds to sound waves.Schwartz's device will stream damp air through a tube and fire light from a laser diode on one side of the tube at a sensor positioned on the opposite side.When sound waves enter the tube through a gap they will vibrate the droplets and the laser sensor should detect the effect optically. The watery ribbon will be very sensitive to faint sounds and introduce no distortion, Schwartz claims.Although such a microphone would no doubt cost a lot to make, some audiophiles are already happy to spend tens of thousands of dollars on turntables that use a laser to play vinyl records. So perhaps a laser-driven microphone could prove a hit too.