27 Jan 2004
Jacqueline Hewett reports from a packed conference session on diode lasers.
It was standing room only at yesterday's conference on high-power diode lasers (HPDLs) which discussed the latest devices and applications surrounding this exciting technology. Here are some of the highlights.
John Haake from US firm Nuvonyx presented three scenarios where HPDLs have been deployed in production environments. In his first example, Haake described how an HPDL system can be used to strip paint.
The setup involves firing 200 µs pulses at a surface with a repetition rate of 6 kHz, which ablates the paint. According to Haake, some 40 m² per hour can be removed in this fashion.
Nuvonyx’s HPDL system replaced a traditional grinding system. Haake said that the laser system saves on labour costs and has lower health risks.
The company has also installed a continuous wave HPDL system in a heat-treating application. Having replaced an Nd:YAG, Haake said the HPDL had less downtime and lower maintenance costs.
The final application was wire-feed welding. Here a 4kW HPLD was used to weld various types of joint on a production line. Haake claimed the HPDL system was both repeatable and faster than existing technologies.
Friedrich Bachmann from Rofin-Sinar highlighted the trade-off that is facing today’s HPDL developers. At present, HPDLs are known to have high efficiencies, low running costs but a poor beam quality. As scientists try to improve the beam quality, this has a negative impact on the cost and efficiency of the system.
Joachim Sacher and colleagues from Sacher Lasertechnik presented details of a compact tunable diode laser with a diffraction limited output of 1 W. The device uses laser diodes in an external cavity and has a center wavelength which can be preadjusted between 775 and 785 nm.
Typical specifications are an M2 of less than 1.2; a mode-hop free tuning range of up to 15 GHz and a side-mode suppression of better than 50 dB. The researchers have used this system to create a Bose-Einstein condensate of over a million 87-rubidium atoms. Sacher concluded by announcing that his team is now working on a 5 W version of this product.