Star Trek Tractor Beam Is Real. Well, Almost!
Still amazed by the tractor beam used in Star Trek? Well, Dr. Tomas Cizmar, research fellow in the School of Medicine at the university of St. Andrews, Scotland has a good news for you. He and his team have successfully developed a working tractor beam that works on microscopic level.
The basic idea behind tractor beam is that it attracts objects towards the light source. Normally light pushes away the objects, but in some case of parameters, this force reverses. The concept here is to generate a optical field that efficiently reverses radiation pressure of the light. During experiment, team used a Gaussian beam, generated by a VERDI V5 laser. After being directed through a lens, the beam passes through a suspension of dielectric spheres set between two coverslips. The incoming and reflecting beam interfere with one another and result in a standing wave. This standing wave, using properties of spheres, tries to push them back towards the laser source.
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According to Dr. Cizmar, the occurrence of negative force is very specific to the properties of the object, such as size and composition. The new technique has got several applications including sorting of macro-molecules organelles or cells.
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The basic idea behind tractor beam is that it attracts objects towards the light source. Normally light pushes away the objects, but in some case of parameters, this force reverses. The concept here is to generate a optical field that efficiently reverses radiation pressure of the light. During experiment, team used a Gaussian beam, generated by a VERDI V5 laser. After being directed through a lens, the beam passes through a suspension of dielectric spheres set between two coverslips. The incoming and reflecting beam interfere with one another and result in a standing wave. This standing wave, using properties of spheres, tries to push them back towards the laser source.
 #-Link-Snipped-#
According to Dr. Cizmar, the occurrence of negative force is very specific to the properties of the object, such as size and composition. The new technique has got several applications including sorting of macro-molecules organelles or cells.
via #-Link-Snipped-#
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