Kathleen G. Tatterson
BALTIMORE -- It's buyer beware as manufacturers of diode-pumped Nd:YAG solid-state lasers seek to replace arc-discharge lamp-pumped devices with the "all-purpose" laser. Users should carefully consider their applications before investing in the most accurate, most powerful and, inevitably, most expensive instruments. That was the advice that laser vendors offered an audience of end users during the Lasers and Electro-Optics Applications Program at this year's CLEO '97 conference.
Laser manufacturers and users alike cite the litany of compactness, reliability, robustness and versatility when describing diode-pumped solid-state lasers in the field and on the floor. Although the attractive qualities of solid-state lasers might seem worth the investment, their appropriateness for the application doesn't always justify the extra money spent, said Steve Guch, executive director of advanced programs at Litton Laser Systems in Apopka, Fla. "Diode-pump arrays are commodities on a price curve reflecting ongoing learning and improvements in economy of scale," he said.
Guch told users to consider a broad range of lasers and to base selection criteria on cost and weight. Also, "reliability" can be a misguiding criterion and should not be considered an issue. "It refers to the number of random failures, not the operating lifetime," he warned.
For example, for applications such as surveying, navigation, target location and marking, and laboratory diagnostics, which require single-shot, low-power, portable or fixed-site lasers from 1 to 20 Hz, lamp-pumping is suitable from a life cycle and cost standpoint. Although diodes can provide a weight savings of up to 3 lb, the initial acquisition price can be $100,000 more per unit. "Life cycle costs are a useful consideration, but don't be a slave to them," said Guch.
The right tool for the job
Users should choose low- to medium-power, diode-pumped high- duty-cycle lasers where high beam quality and efficiency are crucial for precision manufacturing and where replacement of lamps on field platforms is not feasible. Overall, users are encouraged to build a system to fit their needs, whether employing diode-pumped or lamp-pumped lasers, or no laser at all if it works for the application.
So what makes a diode-pumped solid-state laser system appropriate for the job? A good device needs to demonstrate process improvement in an application and use a common technology platform to increase volume, said Curt Fredrickson of Mountain View, Calif.-based Spectra-Physics Lasers Inc. In addition, it needs to be easy to use and service, and should vertically integrate to drive down costs.
Large-volume commercial applications eventually will cut the price of diode-pumped solid-state lasers, said Kenneth L. Shepler of the US Air Force Wright Laboratories. "Despite Department of Defense-funded producibility programs, the advantages of these lasers to military applications are not enough to drive down prices," he said. He predicted that by 2001 development will reach a point where diode-pumped lasers will be as economically feasible as lamp-pumped lasers.