Modern biotechnology is increasingly in need of devices that can move in the space of single biomolecules, cells and other microscopic objects. The first such device, the laser optical tweezers, was developed by the American physicist Arthur Ashkin in 1986, and every year in this area there are more and new technical solutions. Thus, a group of researchers from the Saratov State Technical University and OJSC "NII-Tantalum" proposed and constructed a micromanipulator capable of simultaneously support and move up to 7 microparticles.
We can say that the way to optical tweezers, or by using a more stringent terms, laser micromanipulator, was opened by the outstanding Russian physicist Pyotr Lebedev in his experiments in 1910 to detect the pressure of the light. It is the power of this pressure draws polarized dielectric microparticles in the region of focused laser radiation. And, it turns out, can move them after the focus of the world.
In such a system for the initial capture of the particles must be extremely accurate to combine the focus position and microscopic. Therefore, to simplify the design capture manipulators used axicons — optical elements that focus the laser beam is not a point, and a line segment length of a few millimeters.
On the role of axicons suitable band or holographic plate, regular structures that form in the space of periodic optical patterns. And quite recently, in 2008, the German firm HoloEye start mass production phase modulators — axicons based LCD matrix. Now you can dynamically change the spatial pattern of radiation, and thus assemble complex microstructure.
On the basis of the German phase modulator and a powerful infrared laser research group led by Viloma Bayburina just developed its construction of the optical tweezers. As a result, the resulting system is capable of capturing up to 5-7 and move microscopic objects simultaneously. That is its main advantage — foreign industrial manipulators operate with each particle separately. Such a device finds wide application in the study of cell biophysics. The presence of LCD, and allows independent control of the location of objects without any mechanical intervention and produce complex microstructure.
Source of information:
VB Baiburin, P. Volkov, SD Spitsin, AV Ljashenko "Holographic Laser micromanipulator." Geteromagnitnaya Microelectronics, vol. 2, 2011.