Staff members of P. Lebedev Physical Institute of the Russian Academy of Sciences (FIAN) developed a new technology of direct laser transfer of the substance based on visible light. Operation of equipment capable of reproducing oil paints, lithographing and even drawing microcircuits is possible via computer, as by printer.

Today laser is used in many production processes; it cuts, brazes, melts and sounds different media. In early 21st century this list was supplemented by transfer of the substance under pressure, which occurs in micro-volume under action of light impulse. Ultraviolet devices suitable for display creation, lithography, manufacture of miniature electronic components and power sources have become the main tool of this technology called "direct laser writing". They have a number of indisputable advantages (low boundary energy, insignificant depth of penetration and a potential for resolution increase to several thousands of points per inch). However, they have also essential shortcomings, such as a high price, necessity for a special UV optics and materials resistant to ultraviolet radiation, impossibility of transfer of a great number of elements by one impulse.

A group of researchers from FIAN headed by Alexander Nasibov, Dr. Sc. (Eng.), has offered an original method of "writing", when transfer of the substance is effected by copper-vapor laser operating in the mode of image brightness intensifier. It is brought to the threshold value, which "provokes" emission, for example, of oil-color. Moreover, such technology allows "to copy" not only certain details of a picture, but also its fragments. Scientists proved its efficiency through an experiment: they transferred a picture from the book jacket of Letters to Gala (1999) by French writer Paul Eluard to plastic cards.

The method suggested by FIAN researchers differs fundamentally from other similar methods by its ability to transfer various substances, including solid ones, to the given object, which is impossible for ordinary print-

ers. For example, it opens up a possibility to "paint" a picture without a brush to an artist–first he reproduces it on a computer display and then transfers it to a canvas.

The color gamma of the reproduced fragment depends on a number of pixels*, their diameter and coloring. In other words, the way to a coloristic solution in each particular "point" of a picture lies through control of these parameters. "A drop (pixel) can be, say, 200 µm in diameter, and its certain subpixels can reach 20 µm. It promotes reproduction of the image with a very high resolution and the color will practically be the same as in mixing of colors. According to Nasibov, the size of one subpixel is determined by potentials of an optical system, and, with special equipment available, laser radiation can be focused to a wavelength and even less."

Reproduction of pictures is not the only application of this technology. Alongside with oil-colors, thin films, organic compounds and semiconductor structures can also be used. Therefore, this innovation can be utilized in electronic industry for manufacture of passive elements of microcircuits (resistors, capacities, inductors) and organic lumino diodes (displays) and also for lithographing and marking, including that on metal.

The maximum rate of viscous paint printing by a copper-vapor laser reaches 80 cm²/s, and the maximum area of an image transferred per impulse (with an average strength of 10 W) is ~10² cm².

* Pixel (from the English picture element) is the least logical element of a two-dimensional digital image in raster graphics.–Ed.

According to the data of the Scientific Information Agency FIAN-Inform

Photo from FIAN Internet site

Prepared by Marina KHALIZEVA