The first CO2 laser invented in the early 1960s was DC a glass laser. DC laser technology has not advanced since the 1960s, largely due to the shift in laser technology to RF and all-metal laser design.
A DC glass laser consists of a long, fragile blown glass container that contains a laser gas mixture. Laser optics are attached directly to the glass to seal the laser mixture and form a laser resonator, and a high-voltage DC discharge ionizes the gas inside the glass vessel to generate the laser beam.
Due to the poor heat transfer of glass and the inefficiency of high-voltage DC discharge, DC lasers require special water-cooling equipment for continuous operation. The proper way to cool a DC glass laser is to use a chiller. A chiller is essentially a combination of refrigeration equipment and a pump that recirculates the water around the glass laser, keeping the laser at a constant temperature. Because DC glass lasers use very high DC voltages, water can be very dangerous and even fatal if it comes into contact with high-voltage electronics, especially when combined with cooling water.
Over time, the use of glass as a gas tank and DC discharge between the electrodes can contaminate the electrode mixture as a byproduct of electrode corrosion and gas mixture depletion. Contamination from the gas mixture and consumption of helium escaping through the glass walls and seals reduces the efficiency of the laser and severely shortens the lifetime of the laser.
DC glass lasers are characterized by a very low modulation speed, which cannot be rapidly modulated due to the limitation of continuously turning on and off the high-voltage DC power supply. This greatly limits the speed of laser processing and reduces throughput, especially in imaging applications that require high-quality laser pulses.
Additionally, glass lasers can be damaged by thermal shock from routine handling or interruptions in water cooling. If a cooling flow is not provided to the laser, the glass container will break and the laser will not function properly. This gives DC glass lasers a very limited lifespan, usually measured in months of operation.
DC glass lasers are delicate devices, when integrated into laser material processing systems, they require additional cooling equipment to operate, have lower quality output compared to other lasers, have very limited laser processing speeds, and have a short lifespan.
RF metal lasers have a closed metal chamber that contains a laser gas mixture. Precisely controlled radio frequency energy is used to generate an ionized gas plasma for the laser to generate the laser beam. RF metal lasers are designed to be compact, durable, and have integrated air cooling. Originally developed for demanding military applications, RF metal laser development continues today.
RF metal lasers are the lasers of choice for a wide range of applications in many industries today. These lasers can operate in almost any environment without the need for high pressure and water cooling.
RF metal lasers offer lower cost, are designed to be durable, deliver the highest performance with the highest laser beam quality, offer unlimited lifetime, and ensure operator safety.
Therefore, when considering purchasing a laser system, you should ask the laser system supplier what type of laser is used in the system they offer.