Directed Light, Inc.

DC Arclamps are operated in a continuous wave (CW) mode and discharge a constant current in the 10-40 Amp range between 100-250 Volts. The continuous light radiated induces constant gain in the Nd:YAG rod, generating a continuous laser beam. Krypton gas is almost always selected for CW applications because it is more efficient than Xenon at these power levels; in fact, these lamps are universally known as Krypton arclamps. For increased efficiency, they are filled to very high pressures, typically 5-10 atmospheres. Violent explosions can result from mishandling, so safety glasses should be worn during handling and installation. These high pressures make Krypton arclamps difficult to start because of their high impedance. Therefore, fairly complex starting circuitry must be employed: first, a short duration (approximately one microsecond) high voltage (20-30kv) trigger pulse is applied to the lamp, which causes an initial ionization of the gas. Next, a boost circuit drives a low current through the lamp at moderate voltage for a few milliseconds after which the main power supply can take over and run the lamp at its normal operating current and voltage (typically 20 amps at 150 Volts).

Output couplers, also known as front mirrors, are designed to reflect a portion of the beam back into the laser resonator for continuous amplification while transmitting a portion of the beam to the outside for use. Therefore, the substrate material must be transmissive at the required wavelength of 10.6μ. Germanium and Gallium Arsenide substrates are commonly used for low to medium powered systems. The more expensive Zinc Selenide material is required for higher- powered lasers because of its lower absorption at 10.6 microns.

The outside surface of a front mirror usually has an anti-reflective coating for improved transmission efficiency. The inside surface has a partially reflective coating to reflect a specified percentage of the beam back into the resonator.

Gallium Arsenide (GaAs) is the material of choice in dirty or high- splatter environments. It has relatively high hardness which helps repel debris particles. It also has high thermal conductivity which helps transmit heat away from imbedded particles.

modern chemically impregnated cathodes. To overcome this limitation, “graded glass” seal technology was developed: a glass with a coefficient of thermal expansion in between that of quartz and tungsten is used to join the two dissimilar materials. The glass has a very high melting point so it can tolerate high temperature cathode processing easily but it is more fragile than traditional solder seal and cannot tolerate much mechanical strain. Furthermore, this type of seal does not easily lend itself to automation: skilled glassblowers individually hand craft graded glass seal lamps.

Lasag produced the first pulsed Nd:YAG Laser for welding applications in the electronics industry and over the next few decades established itself in new fields, including medical and aviation. Significant in laser technology was the 1988 introduction by Lasag of a beam delivery using optical fibers for material processing. Lasag continued to bring forth innovations in compact laser devices and pulse power-controlled sources for maximum reproducibility of seam and point welding. In 2003, Lasag launched LightWare™, a cutting edge solution in precision laser welding. Lasag continued to expand its market, setting up offices in Chicago, Italy, Japan and Germany. Lasag continued to develop a series of innovative products and processes, and when it merged with the Rofin Group, a new era of compact, maintenance free welding and cutting lasers was launched. Moreover, the product range of the Lasag processing heads was expanded to include a high-performance triple head able to cut three pieces at once. It is worth noting that this long-established company can point to products still viable after being used for over two decades.