Scientists have made "an acoustic hologram" in the power beam that can move small objects

Surely you've seen repeatedly hologram having a depth of three-dimensional images that occur above or below the flat surface. This three-dimensional effect arises as a result of "the optical three-dimensional space", which is created by the interaction of diffraction and the rays of light transmitted or reflected from the holographic plate. In essence, this is a three-dimensional structure of the light projected into space with the help of an image recorded on a holographic plate.

Light waves are not the only kind of vibrations that can be controlled and with which you can create in the space of three-dimensional structures for such purposes can be used and sound (acoustic) waves. And, unlike light with sound waves can have a direct impact on small physical structures. Researchers at the Public University of Navarra (Public University of Navarre), Spain created a kind of ultrasonic hologram, which allows you to work on small objects, like a force beam space ship USS Enterprise in a series of science fiction films "Star Trek / Star Trek".

Acoustic effects on material objects are usually created by a plurality of ultrasonic transducer or one aimed at a special reflector. In the space between the two elements formed a standing acoustic wave in the minima and maxima which can be kept small objects. Changing the phase of the ultrasonic wave emitted makes minima and maxima move, dragging the held object. This is quite an interesting technology, but it works only within the space enclosed between the emitter and reflector, and therefore it is less interesting than the technology of "Star Trek."

Acoustic hologram is a method of creating three-dimensional space structures consisting of sound vibrations. In this case, these holograms are 20 by 20 array of ultrasonic transducers reproducing the ultrasound with a frequency of 40 kilohertz. Each transmitter is equipped with a kind of acoustic lens that allows you to "focus" the acoustic waves at a certain height above the surface of the emitter. To create a holographic structure, all emitters generate sound waves with a particular phase and amplitude. The interaction of these waves creates a space in the area with pressure drops that may have an impact on material objects.

Forces of these effects is enough to capture and hold a light foam particle diameter of about 3 millimeters, but the main advantage of this approach is that the hologram system has a second reflecting component, and may act in the surrounding space theoretically without any restrictions. Moreover, the creation of complex holographic "paintings" and move allows you to keep several material objects.

The absence of the second element in such a system before it opens a lot of potential applications in various fields. These speakers' power rays "can be used to control the movement of microscopic instruments inside the human body, which, for example, can break up kidney stones or produce microsurgical operations. Alternatively, such techniques may be used to create a "display material" pixels which will be tiny material objects.

At present, the weight and size of objects that can be manipulated with the help of an acoustic hologram depends on the power of ultrasonic transducers. Therefore, taking a strong emitting device can lift and move objects of great size and weight. Unfortunately, this method is unlikely to happen to move people and other living organisms, they rather their cells can not withstand the harmful effects of strong high-frequency acoustic oscillations.