Laser F/X On-line Newsletter - Virtual Visits
A Virtual Visit to Spectronika Ltd.
On the 7th Floor of the now faded former
"National Optics and Laser Institute" in Sofia, Bulgaria,
are the offices and factory of Spectronika Ltd. Started as a private company
in 1992 after the former communist regime ended (1989), the company
specialised in the manufacture of Copper vapour lasers for the domestic and
Eastern bloc market but now exports world wide.
Most CV lasers require a flowing
buffer gas such as Neon and frequent replacement of the depleted copper as
well as water cooling. The Spectronika laser uses a sealed off tube design
with integrated optics allowing the tube to be treated as if it were a
"light bulb" and replaced after 800-1000 hours of operation.
Replacement tubes are inexpensive and can be installed by anyone with
electronics experience in under an hour as they require no optical alignment.
The manufacture of the lasers is done by a small team of dedicated professionals using old fashioned craftsmanship coupled with modern digital technology. The laser tubes are carefully constructed by hand in the tube department using the almost dying craft of glass blowing. The tube is shaped with a series of "dimples" on the bottom to hold the Copper halide which is heated and subjected to a pulsed high voltage arc to dissociate and lase the copper atoms.
After the tube has been formed, the ends are precision ground and cut, the copper halide is inserted into the tube and the windows are installed. The tube is then placed on a vacuum station for pumped down for several hours. Once the tube has reached vacuum, a small quantity of buffer gas is introduced to facilitate the conduction of the high voltage arc between the electrodes.
The tube is then heated with electrical heaters to melt the copper halide into the dimples along the bottom. Once this is completed, the tube is fired with an extra heavy duty power supply and the high reflector [mounted directly to the tube] is aligned. This means that no realignment of the optics is required when the tube is changed. The tube is allowed to "cook" for some hours to remove any remaining impurities within.
The Spectronika tubes have an almost unlimited shelf life as they do not suffer from the "gas clean up" typical of Ion lasers as there is no pressurised gas to seep into the walls of the bore - which in this case, is glass rather than ceramic. The limit on the life span of the tube is imposed by the amount of copper available for lasing and the gradual erosion of the copper electrodes during operation by the high voltage arc within the tube.
The optical windows and high reflector for the lasers are custom manufactured to Spectronika's exacting standards by an associated facility in the same building. The optics lab also manufactures the mirrors and dichroics used in the basic projector built by Spectronika for the domestic club/disco market. The precision mounting for the high reflector is made in Spectronika's own machine shop while some of the metalwork is done in an outside laser cutting facility.
The laser is an integrated unit with tube and power supply in one unit. Inside the laser, the tube is actually mounted in an oven to keep it at the approximately 350 to 450 C needed to vaporise the copper halide. There is a preliminary heater used during the start up cycle to pre-heat the tube, and a precision heater to keep the tube at the correct operating temperature during lasing - both are digitally controlled for precise temperature regulation. The laser takes about 10 minutes to warm up to full power and is cooled with 4 small muffin fans so is virtually silent in operation. The system is ruggedly designed so that even in the event of a power failure, it will not be damaged by lack of fan cooling.
The power supply section of the laser appears deceptively simple but is actually a complex digital system which generates extremely high pulsed voltages in the 9 -10 kV range. The Logic card controls the generation and timing of the pulses delivered to the high voltage transformer. The high voltage pulses are precisely shaped and timed by the thyratron to deliver nanosecond high voltage pulses to the laser tube.
Spectronika currently offers a 5 watt model which usually outputs a bit more than 5 watts, especially in the North American market due to the 60 Hz AC power. Spectronika is presently working on a new model which will offer 10 watts of power in a similar air-cooled package. The prototype model has so far yielded 12 watts for brief periods however the power supply is being re-designed to allow for continuous operation at high power and the new laser will not be available until late in the first quarter of 2001.
While in Bulgaria, we were treated by our hosts to some of the tourist sights and tasty cuisine of the country. Visit the Bulgaria Tourism page for pictures from our trip.
Spectronika lasers offer high power output, air-cooling, unique colours with a brightness factor of 2X, low AC power consumption, integrated head and power supply in a package that weights just under 100 Lbs. [45 Kg], at a very reasonable price.
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