LZH developing first eye-safe high-power ultrafast-pulse lasers

Hannover, Germany -- Researchers at the Laser Zentrum Hannover e.V. (LZH) are developing the world's first 2 μm femtosecond laser source with pulse energies in the μJ range.

For nearly 20 years, the advantages of using ultrashort laser radiation have been known. Because the pulses have been shortened, extremely high peak intensities can be reached even for low pulse energies.

The effects are of this are significant. Materials can be precisely cut and removed, without causing thermal damage to the material. Industry has profited from the advantages of ultrashort-pulsed laser systems where, for example, these laser have been used to produce significantly more effective solar cells, or to improve expensive wafers used for chip production.

By expanding the emission spectrum of an fs laser into the spectral range of 2 μm, but simultaneously keeping the high pulse energies, the LZH wants to open the door for completely new fields of application, such as in micro-material processing, in medical technology, or in nanotechnology. This "eye safe" wavelength also offers a further advantage; safety measures which are normally expensive and place limitations on production are relatively inexpensive for applications with this laser.

The LZH's Laser Development Department plans to construct a compact, regenerative, ultrashort-pulse amplifier, emitting in the wavelength range around 2 μm, with pulse energies up to 50 μJ and pulse durations below 500 fs. "Our goal is a 2 μm fs laser system emitting in the mid-infrared range," explains Dr. Dieter Wandt, head of the Ultrafast Photonics Group which is working on this laser. Wandt says that polymer processing is one important field of application. Using IR radiation, polymers can be cut or welded without using additives.