Lumics Product Catalog 2008 - Lumics - #4

Solid-state lasers are used In a wide variety of applications ranging from materials processing to entertainment to medical treatment. Optical pump sources for solid-state lasers have traditionally been lamp based. Because flashlamps emit light that is distributed over a significantly wider spectrum than most solid-state gain media, much of the energy from the pump light is wasted in the system as heat. Moreover, flashlamps represent a significant consumable expenditure since typical lifetimes are measured in hundreds of hours.

New high power, long lived diode lasers have revolutionized the performance and operating cost associated with diode-pumped solid-state lasersystems. In particular, diode pumping results in enhanced electrical-to-optical system efficiency since diode lasers emit optical energy over a narrow spectrum that closely matches solid-state absorption profiles. Additionally, reducing thermal gradients in the solid-state gain media improves beam quality and laser performance. The lifetime of high power semiconductor laser devices is several orders of magnitude larger than lamps, making Lumics diodes the ideal choice for pumping in present and future laser designs.

The light passes through the NIR-transmitting part and is then absorbed by the second NIR-absorbing part while both parts are clamped together at low pressure. The absorbing material converts NIR to heat and melts at the interface, while heat is also conducted back into the mating surface of the light-transmitting part to create a welding zone. Joint strength can exceed that of the original materials.

A new technology of diode laser systems are fiber laser and direct diodes laser systems which offer a better beam quality and a very high efficiency. Lumics offers fiber bundled direct diode systems and pump laser sources for Ytterbium fiber laser.

Laser-transmission welding is feasible when two materials that respond quite differently to laser light are joined together (see schematic). The method uses near-infrared (NIR) light at wavelengths from around 810to 1064 nm.

Fiber bundled diode laser are available as direct laser or as a pump source for fiber laser systems. Because the architecture is based on single emitter diodes the optical power can be combined into one fiber core with optical fiber pump combiners.

The working principle of a fiber laser is based on an optical fiber which acts as the resonator cavity. The device typically consists of a single mode core doped with Erbium, Ytterbium or Thulium or a combination thereof. Energy from a pump laser is coupled into the cladding of the fiber from which it is reflected into the core and pump the dopant. The output wavelength is typically in the range of 1064nm.

Principle of micro welding with near-infrared light.