Diversity Powers Laser Market

Dr. Steve Sheng

Despite the economic downturn, the future of lasers has never looked better. The next several years will witness continued steady growth in the number of laser applications.

In the past few years, telecommunications has received enormous attention in the laser industry and in the photonics press. While telecom applications continue to offer tremendous long-term potential for laser manufacturers, market diversity remains a core strength for our industry.

As we begin the second year of this millennium, the applications for laser technology are becoming ever more diverse and demanding, including microscopic imaging, marking plastics and semiconductors, automotive assembly, semiconductor fabrication and testing, and electronics packaging. Success in any of these areas is built on lasers that offer the necessary performance (wavelength, power, mode quality) and reliability to make the application both practical and economically viable. Moreover, the laser must be packaged to offer the required functionality, ruggedness and ease of integration, which presents a nontrivial technological challenge. These market forces are driving current and future technology developments in the laser industry.

Many applications in the UV

In terms of performance, the most active product development is occurring in diode-pumped all-solid-state ultraviolet lasers. UV lasers offer two unique advantages: Their high-energy photons ablate materials without causing thermal damage, and their short wavelength enables a sharper focus, thereby enhancing the spatial resolution.

In the past, the only viable UV lasers were gas lasers — excimers and ions. Now, many UV applications depend on the turnkey simplicity of all-solid-state, frequency-tripled (355-nm) and -quadrupled (266-nm) lasers.

These lasers fall into three groups: continuous-wave (CW), pseudo-CW and Q-switched. The maximum output power of Q-switched lasers is rapidly increasing, and they currently can deliver up to 10 W at 355 nm, with pulse energies as high as 600 μJ. Their applications are in micromachining disposable medical products, marking a wide range of materials and precision materials processing, including microvia drilling in the electronics industry. The trend in this product segment is for higher power, which translates into an improved process speed and lower costs.

Today’s Q-switched solid-state ultraviolet lasers deliver 10 W at 355 nm and pulse energies of up to 600 μJ, enabling them to find a place in precision materials processing. Here, a Q-switched UV laser has micromachined 500-μm-thick silicon. Courtesy of Exitech UK.

Pseudo-CW ultraviolet lasers utilize passive mode-locking techniques to generate a high-repetition-rate train of pulses from a cavity as simple and as reliable as a CW laser. The 355-nm versions are beginning to penetrate industrial applications, where their high repetition rate makes them ideal for many applications that formerly employed CW gas lasers. We foresee strong near- and long-term growth for this technology in applications such as reprographics and biomedicine.

There is also a growing demand for industrial deep-UV CW lasers for the production of fiber Bragg gratings and for the inspection of next-generation semiconductor wafers. At present, the 244-nm frequency-doubled ion lasers are dominating these applications, but the new 266-nm all-solid-state equivalents have recently become available and are quickly gaining ground.

Ultrafast Ti:sapphire lasers are the heart of multiphoton fluorescence microscopy, which produced this image, at left, of endothelial cells. Researchers are benefiting from the ergonomics of new, compact single-box products. Courtesy of R. Williams and W. Zipfel.

The high-power semiconductor laser array is the engine driving all-solid-state lasers; in fact, laser pumping remains the biggest application for high-power diode lasers. The trends in this technology are longer lifetime, higher power and improved brightness. And the number of direct applications of semiconductor lasers themselves, such as the welding and cutting of thin metal, will increase as their brightness increases, yielding a higher power density.

Ergonomic issues

For all types of lasers, the keys to wider applications are improving the packaging and offering the best features. An example of this is in the area of ultrafast lasers.

Today, femtosecond and amplified lasers are available to the consumer as compact, single-box products. This simplifies the work of biologists performing multiphoton microscopy, and it enables OEMs to develop new materials processing platforms based on ultrafast laser pulses. Like the latest UV lasers, the ultrafast versions offer expanded automation and remote operation capabilities, via simple software interfaces, to ease their integration into both laboratory and OEM environments.

Serviceability is another feature that is becoming increasingly important. Today’s users cannot tolerate the loss of productivity resulting from a long downtime for scheduled maintenance and repair. Because even the most reliable laser occasionally needs servicing, we are seeing a growing emphasis across the industry on products that are designed for ease of service in the field.

Over the longer term, the market for deep-UV photons will continue to grow. We expect new laser and nonlinear optical materials to enable higher-power lasers for these expanding applications. Moreover, we predict steady and sustained improvement in diode-laser-array (stacking) technology, in part to support industrial applications for kilowatt infrared lasers, including cutting and welding in the automotive industry.

Meet the author

Steve Sheng is senior vice president at Spectra-Physics’ Laser Group in Mountain View, Calif., and the current president of the Laser & Electro-Optics Manufacturers’ Association.