Recently in LASER 2007 Category
Well, it's time to for us to sign off from LASER 2007. Our feet are tired, our notebooks are full, and our heads are full to brimming with all the new technologies presented at the show.
Everyone we spoke to agreed that LASER 2007 was bigger and better that the last event in 2005. Exhibitors reported busy booths, numerous new sales leads, and - even better - customers suggesting new applications that will help to drive future product innovation.
Such was the buzz of the show that Helmut Kessler, general manager of CVI Technical optics, suggested to me that LASER should become an annual event. We'd love to know what you think about this radical - or some would say, logical - idea.
On behalf of the whole optics.org team, we hope you've enjoyed reading our blog. And now we'd like you to do something for us: tell us what you think of our coverage, or any other aspect of LASER 2007, by using the commenting tool at the end of each post. It won't take long, and will play a crucial role in extending the information contained here.
Goodbye, and see you next time!
I found one of the best examples of how laser sources developed for cutting-edge scientific research can drive the commercial optics industry on the Time-Bandwidth booth. The Swiss company, which was set up in 1994 as a spin-off from the ETH Zurich's ultrafast laser physics group, specializes in producing passively mode-locked lasers that generate femtosecond and picosecond light pulses.
Time-Bandwidth's Christoph Rüttimann told me that the company's diode-pumped solid-state lasers were originally developed for research groups to study chemical and molecular processes. But its latest generation of laser modules has also been designed as turn-key solutions for OEM applications such as micromachining, semiconductor processing and medical and life-science diagnostics, where the use of ultrashort pulses enables high peak powers while avoiding thermal damage to the material.
The company's high-power Fortis laser, for example, can produce laser pulses of less than 800 fs at 1030 nm with a repetition rate of 40--60 MHz and an average output power of 50 W. “This is the most powerful ultrafast oscillator system available on the market,” said Rüttiman. “The oscillator-only, amplifier-free design ensures particularly reliable and stable operation.”
What makes Time-Bandwidth's lasers different is the use of a semiconductor saturable absorber mirror (SESAM), a mode-locking element that was first invented at ETH Zurich by Ursula Keller. Time-Bandwidth has continued to work with Keller to improve the device design, the fabrication process and the long-term device reliability to produce a laser system that is robust enough for industrial applications.
The company has SESAM device designs that operate at wavelengths ranging from less than 800 nm to more than 1600 nm, pulse widths from femtoseconds to nanoseconds, and power levels from milliwatts up to 50 W. In the Fortis laser, the SESAM is combined with a thin-disk laser to provide clean and transform-limited pulses, while the Duetto laser module incorporates a passively mode-locked seed laser with a diode-pumped amplifier to deliver 12 ps pulses at 1064 nm with a repetition rate of between 50 kHz and 8 MHz.
Just as the curtain was about to fall on LASER 2007, I found what gets my vote for the most interactive exhibit of the show. Michelson Diagnostics, a UK-based start-up founded in early 2006, was demonstrating its benchtop optical coherence tomography (OCT) scanner and displaying real-time sub-surface images of everything from strawberries to the fingerprints of anyone who stopped at the booth (including me).
OCT works by focusing laser light onto a tissue surface and using an interferometer to mix the reflected light from below the surface with the original light source. The interferometer only detects light that has not been scattered and builds up a picture of the structures below the surface. OCT works to a depth of around 2 mm, after which all returning light will have been scattered at least once.
Gordon McKenzie, the company's applications director, talked me through some of the key features of the turnkey EX-1301 OCT microscope. “We use a swept laser source that continuously scans through a wavelength range from 1260 to 1360 nm,” he said. “We scan at 10 kHz and this gives an axial optical resolution of less than 10 microns (in tissue) and a lateral optical resolution of 10 microns.”
The company's key strength is in the design of the Michelson interferometer. It projects laser light to four different depths to build up the sub-surface image. The images that are displayed on the screen are raw images that have not been processed or enhanced in any way.
McKenzie told me that the company is working with two hospitals in the UK who are using prototype devices to study excised human cancer tissue. One of the hospitals is looking at cervical and oesophageal cancer tissue while the second is concentrating on skin, lung and oral cancers.
And now to the fun bit — seeing a cross-section of your fingerprint. After looking at my middle finger, McKenzie told me that I have “the most worn fingerprint of anyone we've ever scanned”.
I've attached my fingerprint image and a “typical” image to this post so you can make your own mind up. You can see the top epidermal layer and the spiral structures are sweat glands. Also note that the top of surface of my finger is decidedly flat compared with the ridges of typical fingerprint. Must be all this blogging from LASER!
A spectrometer mounted at the top of a tower in a Portuguese forest is helping to spot forest fires before they take hold. In Hall B2 at Laser 2007, Klaas Otten of Avantes showed me the company's Forest Fire Finder, a self-contained detector and tracking system which removes the need for constant human observation.
The device consists of an Avaspec-2048-USB2 spectrometer attached to a video camera and a telescope, mounted alongside a control unit, a communications system and weather monitoring apparatus. The telescope and camera constantly scan 320 degrees of the horizon while the spectrometer analyses the light from the telescope, collecting spectra from up to 15 kilometers away. When it detects the smoke from a fire, the communication system sends an alert to the local operations center by SMS, GSM and over the internet, telling them the location and the weather conditions. It even transmits images of the fire, so the fire fighters know what awaits them when they arrive.
The spectrometer employed is a standard Avaspec machine, and there's nothing revolutionary about using it to detect atmospheric smoke and fumes, but the complete stand-alone system employed in Portugal is a novel implementation which has been well received by the local authorities. With little modification the system could be installed in other forested areas around the world, allowing a relatively simple laser system to play a big part in saving lives and protecting property.
When it came to deciding on a name for Modulight's new range of 635 nm high-power laser diodes, applications engineer Matei Rusu told me that the decision was easy: “They are red, they are hot and so it had to be ChiliLase.”
The 635 nm ChiliLase diodes emit 4 W from a CS-mounted bar or 3 W from a fiber-pigtailed module. “There are 19 emitters in the bar,” said Rusu. “We grow these by MOCVD at our facility in Tampere in Finland and they emit directly at 635 nm. There is no frequency doubling involved.”
Modulight couples the emission from each individual emitter into a fiber and then uses its optical expertise to couple the array of fibers into a single 200 micron core fiber.
For both the 4 W bar and the 3 W pigtailed module, Modulight quotes an operating current of 10 A and an operating voltage of 2.5 V.
Rusu hopes that the diodes will find medical applications, such as photodynamic therapy to treat skin cancers. Here, the module would be used to activate a light-sensitive compound that preferentially accumulates in cancer cells.
Modulight was founded in 2000 and its mission is to “add value to optical applications”. Business at the firm is flourishing: the company posted record revenues in 2006 and sales have grown for the third year in a row. In 2006, it also secured a contract from the US security market to supply lasers for perimeter monitoring.
A new addition to the Coherent booth is the Nuvonyx portfolio of high-power laser diode systems for industrial materials processing. On show was the first in the new range of HighLight direct-diode products, a 4 kW direct-diode system that can be used for surface cladding, heat treatment and welding applications.
John Haake, who originally worked for Nuvonyx and is now Coherent's director for applications engineering and product management, stressed the importance of the acquisition for both businesses. “You need vertical integration to succeed in the laser diode market,” he said. “Coherent has a lot of expertise in producing laser diodes with good beam quality, while we know how to put high-power laser diodes together to form a multi-kilowatt source.”
One key application for the 4 kW system lies in surface cladding, in which a material in powder form is applied to the surface of a metal part to provide it with particular functional properties, such as improved wear resistance. The system, which incorporates an array of 808 nm laser bars and micro-optics technology to shape the beam output, can form a cladding layer with a width of about 10 mm at speed of about 0.5 m per minute, depending on the demand of the application. That means that about 3 kg of powder material can be applied every hour.
According to Haake, using lasers for such large-area surface cladding applications delivers equal, if not better, performance than conventional techniques such as TIG (tungsten inert gas) and plasma welding, but can be much quicker because only a single pass is required to produce the cladding layer. In contrast, conventional arc-welding processes nearly always require multiple passes to achieve a cladding layer with the required material properties.
Matthias Schulze, Coherent's technical marketing director, says that the Nuvonyx business will shortly become integrated into the organization as the company's direct-diode division. “Materials processing is a growth target for us,” he said. “Direct-diode applications offer excellent opportunities to replace traditional materials processing techniques with laser-based technology.”
Optics giant Carl Zeiss presented its prestigious research award at LASER today. In a ceremony rounded off with music from a woodwind trio, delegates saw Jun Ye from the University of Colorado at Boulder, US, pick up the award and a cheque for €25,000. Ye received the award “for his work on the application of femtosecond frequency combs”.
The award is presented every two years and is given to younger scientists for their achievements in basic optics research. “Research, development and innovation are very important to Carl Zeiss,” company CEO Dieter Kurz told the audience. “Carl Zeiss invests 11% of its annual revenues back into R&D.”
Ye is the tenth recipient of the award and is certainly in good company. Past winners include Eric Cornell and Ahmed Zewail, who have both gone on to receive a Nobel Prize, as well as microscopy expert Stefan Hell and blue laser/LED pioneer Shuji Nakamura.
This is the first time that Zeiss has chosen to present the award at LASER. According to Kurz, LASER is the ideal place as it attracts an international audience and showcases the achievements and innovations that see the optics industry maintaining strong and healthy growth.
Juergen Mlynek, a member of the Ernst Abbe Fund award committee, summed up Ye's achievements before presenting the award. “Ye's work on strontium atoms has significantly broadened the use of femtosecond frequency combs, particularly for atomic clocks,” said Mlynek. “This invaluable research will address scientific questions and at the same time find practical applications. This is also the spirit of Carl Zeiss.”
With so many companies entering the fiber-laser market at Laser 2007, established fiber-laser manufacturers could be forgiven for lamenting the loss of the near-monopoly status they once enjoyed. Not so David Parker, CEO of the UK's SPI Lasers, who believes that increased competition in the fiber-laser space will open up new applications and drive future growth.
Not that SPI Lasers is standing still. At Laser 2007 the company is introducing its first high-power fiber laser modules for use in OEM applications. Each module produces up to 400 W, but they can be stacked together to create much higher power outputs. “The module is extremely thin to allow full scalability from 400 W to a few kiloWatts,” Parker told optics.org. “We've taken our technology to create a building block for OEM manufacturers.”
According to Parker, fiber lasers now offer a more viable solution for industrial processing applications. “Fiber lasers were more costly than flash-lamp lasers, and potential purchasers were wary of the risk associated with adopting new technology,” he said. “Long-term reliability has now been demonstrated in the field, and CAPEX has also fallen.”
Parker acknowledges that fiber lasers are challenging and replacing traditional laser sources in some material processing applications, but points out that SPI's products are also being used in new applications that will expand the overall laser market. “Medical aesthetics as a market didn't exist before fiber lasers,” he said. “We can't predict what new applications we will find for our products over the next few years.”
Indeed, SPI has achieved much success in the medical market with its 10 W fiber-laser module, and has now introduced a 20 W module operating at 1565 nm that will increase the processing speed and open up new applications for the product. SPI is also launching a range of 100 W and 200 W water-cooled fiber lasers for micro materials processing, and is previewing two new 300 W products – due to be introduced early next year – that will be optimized for cutting and welding applications.
Two of Germany's biggest players in the lasers and optics market, Trumpf and Jenoptik, have established a joint venture. Today I caught up with Jens Bleher, managing director of Trumpf's Laser Technology business group, to find out some more details.
“Both parties will have an equal 50% share of the new company, which will be called JT Optical Engines,“ Bleher told me. “Establishing this joint venture will allow us to accelerate the development of optical engines for fiber lasers. The new company will be based in Jena, a strong optical knowledge base, and will initally have 20 members of staff.“
Bleher describes an optical engine as a fiber laser resonator. It comprises a fiber-optic assembly and the interfaces through which the pump beam enters and the final emitted beam leaves the cavity. It does not include a power supply or cooling, for example.
Research and development is still ongoing at this stage but the plan is to sell the optical engines to third parties and also back to the parent companies Trumpf and Jenoptik.
Trumpf has made it thoughts regarding fiber laser technology crystal clear at LASER this year: the focus is sub-kilowatt systems for precision cutting and welding. This thinking is mirrored in the initial plans of the joint venture. “The current priority is to expand the market for low-power fiber lasers (less than 1 kW),“ said Bleher.
This is not the first time that the companies have teamed up. As Bleher explains, the companies are already working together to develop high-power diode lasers. “Trumpf has held a 25.1 percent share of Jenoptik Laserdiode since 2001,“ he said.
On a final note, the joint venture still requires antitrust approval.
On show at the Fraunhofer IOF booth is a new vibration-compensated mini-projector that could be integrated into mobile hand-held devices. A spokesperson at its booth (B2 261) told me that that every mobile phone maker is interested in this technology, and Fraunhofer hopes that the device will be integrated into all mobile phones by 2010.
The mini-projector will allow a user to project images directly from their mobile phones, as well as from poratble hand-held projectors. The device could also be used as a head-up display in cars, and could be integrated into games consoles.
The prototype on display at the Fraunhofer's booth is a monochrome and full-colour projection system with 640x480 pixels, but the organization hopes to make 800x600 pixel displays in the near future. It incorporates an inertial measurement unit that detects and compensates for any small movements, which is particularly useful for hand-held devices.
The projector also houses an electronics system that converts a digital signal into an analogue signal. This signal is then projected by laser beams onto a 1 mm diameter deflecting mirror, which in turn projects the image in a TV-like scan. The mirror oscillates in two perpendicular directions at an angle ranging from -10 to + 10 degrees to produce the image.
This research was carried out in collaboration with Fraunhofer IOF and IPMS.
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