WORLD OF PHOTONICS - Laser 2007: of green apples and fiber lasers

Mention Munich to most people and it probably conjures up thoughts of the Oktoberfest and beer. But for those who attended Laser 2007 in June, Munich is (for the moment anyway) more likely to bring to mind green apples and fiber lasers. Show organizers had arranged for almost all exhibitor booths at the event to be adorned with large vases (some several feet tall) filled with green apples-and as though to emphasize the applications orientation of the event, each and every apple had been laser marked with “LASER 2007 World of Photonics.” And while every stand did not in fact contain a fiber laser, one could easily have come to that conclusion, as more than 50 companies exhibited fiber lasers-several for the first time-spanning the power spectrum from a few watts to multiple kilowatts.

New fiber-laser offerings included the TruFiber 300 from Trumpf (Ditzingen, Germany)-a single-mode fiber laser with output of 300 W targeted at precision cutting and welding applications; rack-mountable ytterbium industrial fiber lasers from GSI (Rugby, England) that deliver from 50 to 200 W single-mode output; and a new fiber-laser platform from Newport (Irvine, CA) with systems at 100 and 200 W single-mode.

Pumps for solid-state lasers (including fiber systems) were also much in evidence. Based on chips from its Zurich facility, Bookham (San Jose, CA) showed a high-power uncooled multimode laser module for fiber-laser pumping that delivers 8 to 10 W output at 940 to 960 nm. Alfalight (Madison, WI) showed an 808 nm diode laser for pumping applications that produces 2 W of power at 52% peak power-conversion efficiency. And nLight (Vancouver, WA) says its new 30% fill factor 790-to-830 nm laser bar will address pumping, industrial, medical, and defense applications, and combines high brightness with high power, producing 60 W output.

High-power direct diode

On the direct-diode front, the Coherent (Santa Clara, CA) showed the first in its new range of HighLight direct-diode products. Targeted at surface cladding, heat treatment, and welding, the 1-to-4 kW direct-diode systems emerged from the company’s recent acquisition of Nuvonyx. With the Highlight products, Coherent aims to expand interest in direct-diode applications, especially in converting nonlaser applications to laser, says Matthias Schulze, director of technical marketing.

Frequency-converted diode-pumped solid-state (DPSS) or diode-laser offerings highlighted the ever-expanding range of wavelengths available in a small footprint. Cobolt (Stockholm, Sweden) introduced a 515 nm device producing 25 mW; Oxxius (Lannion, France) demonstrated its line of monolithic DPSS devices with outputs from 375 to 561 nm; and JDSU (Milpitas, CA) showed a compact 488-nm-output laser. Newport and Coherent booths featured their Excelsior and Cube ranges, respectively. The expanding range of wavelengths has also prompted the launch of a novel integrated multilaser engine by Point Source (Hamble, England)-dubbed the iFLEX-Viper, the engine incorporates up to six laser wavelengths, covering the entire visible spectrum range from 405 to 640 nm. It includes a mix-and-match choice of diode, gas, and DPSS laser types with a power of up to 50 mW per line.

Newport showcased the latest technology advances in its 488 nm Excelsior and Cyan laser product lines. Demonstrations included a 100 mW Excelsior-488, which is six times smaller than other lasers of similar type and power, according to Ellen McGuirk, vice president of corporate marketing for Newport. A 75 mW Cyan laser and a 20 mW Cyan power-adjustable laser were available for people to test on the show floor. The lasers are drop-in replacements for existing lower-power versions, noted Jürgen Niederhofer, product manager for Newport’s Spectra-Physics Lasers Division.

Osram Opto Semiconductors (Santa Clara, CA) exhibited what the company says is the world’s first surface-mountable (SMT) and smallest continuous-wave high-power laser (see figure, p. 22). Only 6 × 4.5 × 2.5 mm in size, the device emits up to 6 W at 810 nm and operates at temperatures from -40°C to 100°C. It is intended for volume applications such as night vision, closed-circuit television, and traffic monitoring, as well as medical applications such as epilation.

A novel concept in optical-sensing instrumentation was on display at the Ocean Optics (Winter Park, FL) booth. According to Jason Eichenholz, vice president of R&D, the Jaz family of stackable, modular, and autonomous components work in unison to become something greater than the sum of its parts. Jaz modules-which include such functions as spectrometer and oxygen sensor-share common electronics and communications and can be powered by battery or via USB or Ethernet connections. Modules can also be custom configured.

Adding to its growing range of spectroscopy solutions, Andor Technology (Belfast, Ireland) launched two new spectrographs at Laser 2007. The Shamrock SR-500 and SR-750 offer ultimate resolution for more detail and clarity across a wide range of applications including Raman and fluorescence, according to the company, which also announced details of third-party agreements with two new specialist spectrograph manufacturers, Headwall Photonics (Fitchburg, MA) and Specim (Oulu, Finland).

Technical presentations and awards

The technical World of Photonics Congress associated with the trade fair was organized in a collaboration among show organizers (Messe München International) and several international science societies and included a number of concurrent meetings-the European Conference on Biomedical Optics, Lasers in Manufacturing, and CLEO Europe/IQEC, to name a few. Together these meetings presented-in more than 2000 papers-a wide-ranging picture of optics and photonics developments across its various fields.

In one example, lead researcher Ingrid Wilke, assistant professor of physics at Rensselaer Polytechnic Institute (Troy, NY), discussed her team’s work with ultrafast lasers as a microinjection method that can preserve the integrity of cells. The technique could one day allow doctors to perform nanosurgery on individual cells (see also www.laserfocusworld.com/articles/276746).

In another session, Kevin Kelly of Rice University (Houston, TX) delved into the most recent work he and his group are doing on single-pixel cameras based on time-multiplexed random sampling and optical compression techniques (see www.laserfocusworld.com/articles/277164). Topics of poster sessions at the Congress ranged from laser-gain materials to biophotonics to quantum cryptography.

Also during the week the Carl Zeiss Research Award was presented to Jun Ye. Born in Shanghai, China, Ye is now a physics professor at the University of Colorado at Boulder. He was honored for his experimental work in femtosecond lasers and frequency combs, which expanded on that of John Hall and Theodor Hänsch-winners of the 2005 Nobel Prize for physics.

A former winner of the Carl Zeiss award was also honored during a plenary session at Laser 2007. Stefan W. Hell of the Max Plank Institute for Biophysical Chemistry (Göttingen, Germany) was presented with the 2007 Julius Springer Prize for Applied Physics for his invention of the stimulated-emission-depletion (STED) microscope that allows noninvasive imaging of the inside of cells.

Upbeat atmosphere

Exhibitors and show organizers were pleased with the event, which attracted more than 25,000 visitors and 1008 exhibitors to Munich-increases of more than 10% and 6%, respectively, compared to the previous show, Laser 2005.

Characterized by generally larger booths and a more social environment on the floor (coffee, ice cream, and of course beer were all flowing freely) than its North American counterparts, this year’s Laser apparently left most visitors with a strong sense of a buoyant business environment, lots of new products, and some intriguing applications advances. The next Laser will take place in Munich June 15-18, 2009.