Q-Switch Works with Ordinary Cooling Water
May 2008Gooch & HousegoRequest Info
• 1064-nm wavelength
• 100-W RF power rating
• >1-GW cm–2 damage threshold
Gooch & Housego plc has developed the Stallion, a water-cooled acousto-optic Q-switch for high-power pulsed Nd:YAG laser systems, both lamp and diode-pumped, as used for laser marking, engraving, cutting or drilling, and for surgery and lithography.
Acousto-optic Q-switches are special modulators designed for use inside laser cavities. They have low insertion loss and can withstand very high laser powers; however, cooling typically is required for them to do so. In normal use, a radio-frequency (RF) signal is applied to the Q-switch, causing it to deflect a proportion of the laser beam. This increases the cavity losses and prevents lasing. When the RF signal is switched off, the cavity losses decrease rapidly, and an intense laser pulse evolves.
But changes in the way that industrial laser cooling has been implemented over recent years have created the requirement for a device with better corrosion resistance. To address this, a new manufacturing method has been developed that eliminates the need for any special treatment of the cooling water. This proprietary technique successfully combines the corrosion-resistant properties of stainless steel with the power handling of aluminium, offering RF power handling capabilities up to 100 W. As a result, the Q-switch can be cooled with ordinary water, and the product lifetime can be extended, production downtime reduced and engineering costs cut.
Optically, the 1064-nm device exhibits low insertion loss of ≤6% static at 50-W laser power and a high damage threshold of >1 GW cm–2 by combining top-grade fused silica with high-quality optical finishing and antireflection coatings. Custom configurations are available for specialized applications, including alternative housing options, wavelengths and radio frequencies.