The Laser Listening Device (Laser Microphone) is a highly sophisticated surveillance apparatus that utilizes an invisible infrared laser beam to eavesdrop on a target. This is the most effective long-range laser listening device in the world that allows the operator to conduct an undetectable surveillance operation on any targeted room with at least one window at an impressive distance of over 500 meters. Laserski mikrofon - laser microphone Laser eavesdropping is designed especially for tactical advantage. The device is easily portable and assembly takes only a few minutes. The long-range laser audio surveillance device is a sophisticated unit designed for use in situations when a building cannot be accessed to place a room monitoring transmitter. This is the most advanced laser listening device in the world and will allow the operator to monitor conversations in a room from over 450 metres away. The laser listening device utilises a high-powered infrared beam that, when pointed at a window, is able to detect minute vibrations in the glass created by the sound of people talking. Using these vibrations the device is able to transmit the conversation by bouncing the vibrations back through the infra-red beam to a receiver where they are filtered, amplified and fed into the device's amplifier. The long-range laser audio surveillance device is a highly covert surveillance system due not only to the range at which it can be used but also due to the infrared laser beam being completely invisible to the naked eye. To further camouflage the device both the transmitter and the receiver are built into standard SLR cameras making the whole system look like a photographic set up and allowing for perfect concealment. The laser audio surveillance device is a precise unit that relies on the specific alignment of the transmitter and receiver and as such is supplied with sturdy tripods for both components. Included within the price of the device is a three day training course to ensure the best results possible for any surveillance operation. The training will take place in Germany (travel and subsistance not included). The laser listening device is supplied in a robust flight case with all necessary accessories, for full specifications details please refer to the 'specifications' tab.
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A laser microphone is a surveillance device that uses a laser beam to detect sound vibrations in a distant object. This technology can be used to eavesdrop with minimal chance of exposure. The object is typically inside a room where a conversation is taking place, and can be anything that can vibrate (for example, a picture on a wall) in response to the pressure waves created by noises present in the room. The object preferably has a smooth surface. The laser beam is directed into the room through a window, reflects off the object and returns to a receiver (for example a solar panel) that converts the beam to an audio signal. The beam may also be bounced off the window itself. The minute differences in the distance traveled by the light as it reflects from the vibrating object are detected interferometrically. The interferometer converts the variations to intensity variations, and electronics are used to convert these variations to signals that can be converted back to sound. However, countermeasures exist in the form of specialized light sensors that can detect the light from the beam. Rippled glass can be used as a defense, as it provides a poor surface for a laser microphone. However, by simple extrapolation it should be easily possible to adapt this technique to a maser or focused microwave beam in order to fire the beam through ordinary building materials and bounce it off of internal metal objects such as heating ducts or filing cabinets. At this point the only acceptable defense is electromagnetically and acoustically isolating the interior of the structure.
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The technique of using a light beam to remotely record sound probably originated with Léon Theremin in the Soviet Union at or before 1947, when he developed and used the Buran eavesdropping system. This worked by using a low power infrared beam (not a laser) from a distance to detect the sound vibrations in the glass windows. Lavrentiy Beria, head of the KGB, had used this Buran device to spy on the U.S., British, and French embassies in Moscow. It has been reported that the National Security Agency makes use of laser microphones. On 25 August 2009, U.S. patent 7,580,533 was issued for a device that uses a laser beam and smoke or vapor to detect sound vibrations in free air ("PSPYculate Flow Detection Microphone based on a laser-photocell pair with a moving stream of smoke or vapor in the laser beam's path"). Sound pressure waves cause disturbances in the smoke that in turn cause variations in the amount of laser light reaching the photo detector. A prototype of the device was demonstrated at the 127th Audio Engineering Society convention in New York City from 9 through 12 October 2009.
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