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Meetings report
Meetings Report
Optics & Laser Technology
Industry shows flourish Earlier this year, the optics community had the chance to visit probably the largest conference and the largest exhibition in its calendar. Unfortunately, these t w o events were separated by a month and the small matter of the Atlantic Ocean. This year's CLEO/QELS meeting was held in Baltimore, USA fi-om 22-26 May, while the biennial LASER show was held in Munich, Germany from 19-23 June. Between them, the t w o events are good guides to the current state of optics and laser research and development as well as indicators of the industry's health. Comparing the t w o events also reveals the different emphases between the US and Europe.
CLEO/QELS
95 -
Baltimore,
USA
The 15th annual Conference on Lasers and ElectroOptics (CLEO) was held concurrently with the 5th Quantum Elcctronics and Laser Sciences conference (QELS), resulting in arguably the largest conference covering optics and lasers in the world. The event claimed to have more than 1200 refereed papers in over 20 topic areas. Unlike the Munich LASER show, at CLEO/QELS the emphasis is very definitely on the conference rather than the exhibition However, one of the problems with this is that, with up to eight sessions running in parallel, it can be difficult tinting things properly in order to see a desired presentation or to meet speakers. That apart, the s e s s i o n s were generally well organized, and certainly covered a wide range of subject areas. [lnlike, say, ten years ago, when a significant proportion of laser research was funded by the defence industry, and the papers submitted to conferences reflected this, these days the topic areas are much more
Baltimore harhour i s j u s t a short walk fronT the conference centre
widely defined with papers coming from many sources (although, naturally, there are still many papers emanating from military/defence establishments). For example, as well as conference sessions on the theory and current technology of various types of lasers and materials, there were also sessions on the therapeutic applications of lasers and electro-optics, optical sensors for medical applications, eye safe lasers, as well as new developments in biomedical microscopic imaging. On the Thursday of the week-long event, the "Joint s e s s i o n on emerging applications of fluorescence to biophysics and cellular imaging" too],: place. This consisted of a number of invited papers looking at the future potential of optical techniques to biolnedical applications. For example, Brian Herman et al. from the University of North Carolina looked at high-speed fluorescence microscopy, and described some biomedical applications of this new type of high-speed microscopy. By using optical microscopy and environmentally sensitive fluorescent probes, one can study the chemical and molecular dynamics of intact cells. R. Nitschke and K.R. Spring of the National Institutes off Health described the applications of electro-optic and laser technology to fluorescence microscopy. They have modified a video-rate confocal attachment to an inverted microscope to study better living cultured epithelial cells stained with fluorescent dyes. Their use of electro-optics enabled ewitation-ratio imaging and emission spectral scanning. To complement the biomedical conference s e s s i o n s , this year there was a 'biomedical passport four'. This was designed to highlight to exhibition visitors those companies with products and services directly related to biomedical applications. Among the new products was a system designed for laser acupuncture treatments. Launched by OZ Optics, the complete laser diode to fibre delivery system is compact and can be either battery operated or powered by an optional AC to DC converter. The delivery s y s t e m uses a 635 nm visible laser diode. Deliver),, systems with up to 12 mW of output power are available. Also introduced at CLEO/QELS was the "SapphiRe" optical fibre. Launched by Saphikon, these sapphire optical fibres can be used for applications in surgical erbium laser delivery - for example in surgical laser delivery, in ophthalmology, dentistry and general surgery - as well as in applications such as high-temperature thermometry, spectroscopy and other infrared sensing applications. These sapphire fibres have a transmission superior to quartz beyond 2.5 ~tm, so making them suitable for erbium:YAG laser delivery, in addition, sapphire is biocompatible, non-cytotoxic, inert and USP Class VI approved. With a high laser damage threshold and a high melting point (over 2000 C) sapphire offers a significant improvement over other infrared fibres. The
0030-3992/95/$10.00 :d: 1995 Elsevier Science. All right reserved Optics & Laser Technology Vol 27 No 5 1995
ix
Meetings Report 'SapphiRe' fibres have a wavelength range from 0.25 to 3.5 ~tm and a maximum attenuation at 2940 nm of 3 dB m d. However, the company has also demonstrated a loss below 1 dB m ] and, as fibre development proceeds, hopes to have these fibres available soon. Suitable for certain medical applications - such as contact surgery and prostate treatment - as well as for micro-welding, soldering and other materials processing applications, high-power diode laser systems were launched at CLEO/QELS by Opto Power Corporation. The OPC-B015-FCTS was claimed to be the only 15 W microprocessor-controlled diode laser system on the market. Pulse widths from 200 ~ts to CW, and repetition frequencies from single shot to 1 kHz can be set on the instrument's panel. Optics and laser techniques in biomedical applications may have a bright future, but one of the more traditional topics at CLEO/QELS meetings is that of laser fusion technology. This year, I. Okuda et al. from AIST, MITI, Japan described the status of the development of the super-ASHURA KrF 8 kJ, 12-beam laser. Its electronbeam-pumped main amplifier has already demonstrated a considerably enhanced electron-beam-deposition efficiency. J.J. Armstrong et al. from the University of Rochester described fabricating diffractive and refractive optical components for implementation on the 60-beam Omega laser (see Opt Laser Technol 27, page vi). Continuousmask photolithography and replication have been used in the fabrication of the large aperture ultraviolet components. As well as the continuing research into achieving power from fusion, lasers are also finding applications in many environmental areas. The CLEO/QELS session on atmospheric, space and ocean optics covered many such applications. For example, T.P. Grayson et al. from the US Air Force Wright Laboratories presented the design of a novel frequency-agile laser radar system. The system is based on an optical parametric oscillator (OPO) using periodically poled lithium niobate as the non-linear medium. Applications of this system include threedimensional remote hard-target imaging at eye-safe wavelengths, multispectral imaging and differentialabsorption spectroscopy. In the same session, Ryoichi Toriumi and colleagues, from the Tokyo Gas Company and Chiba University Japan, discussed the development of a differential-absorption lidar system based on a solidstate Ti:sapphire laser. The system was developed for nitrogen dioxide monitoring of diesel engine emissions. One of the special features of this year's CLEO/QELS was a birthday symposium in honour of Charles H Townes. Not only is 1995 the 35th anniversary of the first operating laser, but it also marks the 80th birthday of Townes, who invented the maser/laser principle and, in 1954, developed the first maser. This symposium was chaired by Nicholas Bloembergen and included contributions from people who have worked with Townes, including Arthur Schawlow and Boris Stoicheff. As well as the CLEO/QELS parallel sessions, there
x
were also three poster sessions, held on three consecutive lunchtimes. These proved popular, as always, as they enabled a far greater interaction between authors and visitors than was possible in the normal technical sessions. With over 5500 registered attendees at CLEO/QELS and several hundred companies in the exhibition hall, there was always much to see, and many products, both new and old, on display. Among the many new products was the Nd:YAG system from Big Sky Laser Technolo'gies, who claim their laser head is more than 55% smaller by volume than its closest competitor. The power supply/cooler unit is said to be 70% smaller. Designated the CFR200/MINICE, this laser can be used for traditional pulsed Nd:YAG applications but, because many of these applications are moving from the laboratory into the real world, this laser system has been designed for portability and to withstand the harsh environments associated with field or industrial use - the system is completely environmentally sealed to enable operation in almost any environment. In addition, the system has been designed as a 'plug-and-run' tool, to the extent that most users will not even have to align the system. Consequently, the system is suitable for OEM integration into instruments where the user simply wants the laser to perform its function and does not want to spend time doing numerous alignments and continually having to tweak the system. Applications include lidar, remote sensing, laser induced breakdown spectroscopy, laser induced fluorescence, laser ranging and laser induced ultrasound. Another laser launched at the meeting was the Series 142 CW single-frequency visible laser from Lightwave Electronics. This is a diode-pumped, compact, low-noise 532 nm laser for use in applications including interferometry and holography. As well as having the frequency stability, narrow linewidth, dual wavelength option, frequency scan and low-noise features of the company's 140 series, the 142 laser has higher power, a rounder beam, faster locking, lower cost and smaller size. With its OEM design, all control electronics are within the small laser head. The CW power levels available are 10, 20, 50, 100 and 200 mW. In addition to this, and a number of other new lasers - for example the series 210 Q-switched infrared laser, and the series 240 CW visible laser - Lightwave Electronics also announced an agreement with Sony Corporation, in Tokyo, for the joint development of diode-pumped solid-state ultraviolet lasers for applications in microlithography, optical disk mastering and microscopy. This ten-year agreement licenses Lightwave to use Sony's proprietary technology in nonlinear optical crystals to develop and commercialize CW and pulsed ultraviolet lasers and green laser devices. According to Bob Mortensen, president and founder of Lightwave Electronics, 'Lightwave's collaboration with Sony will accelerate the commercial development of ultraviolet applications in critical markets with significant growth
Optics & Laser Technology Vol 27 No 5 1995
Meetings Report potential'. The market for UV lasers is estimated to be $100 million and growing at 30% annually. Traditionally, the C L E O / Q E L S event alternates between Baltimore, Maryland, on the East coast of the USA and Anaheim, California on the West coast. Consequently, next year's meeting will be held in Anaheim from Sunday 2 June to Friday 7 June 1996.
L A S E R 95 -- M u n i c h , G e r m a n y
While the Baltimore conference centre is undoubtedly an excellent facility, with all the charms of its harbour-side location, it is hard to beat the facilities of the Munich LASER show. Not only quality of the trade fair halls themselves, but also the delights of the capital of Bavaria - from the exceptional and world-class museums and galleries (well over 30 of them), to the historic and attractive old centre with its numerous watering holes (where the beer is often drunk in litre glasses!). Unlike C L E O / Q E L S , the emphasis at the biennial LASER show is clearly on the exhibition: this year it filled seven huge halls. This is not, however, to downgrade the associated conferences, which not only included the LASER congress, but also the European Symposium on Optics for Environmental and Public Safety, and a ,joint German-Canadian workshop. The figures for the L A S E R event are quite staggering, with over 14 200 industry visitors from 61 countries, and over 700 exhibitors from 23 countries. In fact, this is an increase in exhibitors by about one third over the 1993 event and an increase of visitors by about 5%. Even the number of conference participants increased by 15%. This certainly places the LASER show as one of the world's largest optics and laser-based events and it shows with the imagination and effort that many of the exhibitors put into their stands.
The tw#l towers ,,?[the Frauenkirche, near to the Neues Rathaus. have become a symbol o[ Munich
Optics & Laser Technology Vol 27 No 5 1995
Compared with the previous L A S E R event, in 1993, the conference has also expanded. For example, the 1993 session on 'Lasers in Environmental Measuring' had effectively changed into the 'European Symposium on Optics for Environmental and Public Safety'. Likewise, the 1993 conference on 'Lasers in research' had 31 papers, while this year it had increased to 59 papers. It included sessions on lasers, lasers in chemistry and biology, quantum optics and ultrafast lasers, as well as a series of invited talks on lasers in research. Other conferences covered such topics as advanced solid-state lasers, optical measuring techniques, lasers in medicine, lasers in microstructure technology, and optical components and systems. As at the C L E O / Q E L S , there was a large contingent of Canadian companies, but at LASER, not only was there a section of the exhibition devoted to over 20 Canadian companies, there was also a joint GermanCanadian laser workshop. This was to provide an update of G e r m a n - C a n a d i a n collaborative projects in laser technology. In 1994, under the direction of the G e r m a n Ministry for Education, Science, Research and Technology (BMBF) a mission to Canada took place, which resulted in numerous possibilities for collaborative research between partners in the two countries. Topics covered in the workshop included (unsurprisingly) a number of success stories of Canadian-German cooperation, in the fields of diode-pumped N d : Y A G lasers, beam control of" industrial N d : Y A G lasers, fibre sensors and fibre lasers. Presentations were given, for example, describing the theoretical and experimental investigations into the supply of pulsed laser radiation to engineering materials, and also on the monitoring of penetration depth in laser beam welding. Other countries, as well as the Canadians, also had their own section of the exhibition. For example, in addition to all the large US companies exhibiting, there was also a group of US companies gathered together under the title ~Made in America'. Likewise:, a number of U K exhibitors could be found in Hall 3. Unlike C L E O / Q E L S , however, there were also a number of exhibitors from the Russian Federation. As well as all the exhibition stands bombarding visitors with information on all the (new and not-sonew) products on display - including three-dimensional video displays, high-power laser diodes and diodepumped solid-state lasers there were also many exhibitors who were universities and/or research institutions. Along with the congress, this helped give the event a research bias, rather than it being just another trade fair. Not only was there work from, naturally, a number of G e r m a n universities and research institutes (from both the former West and East Germanies) on display - for example, the various branches of the F r a u n h o f e r Institute -- but there was also a chance to see the R & D work being carried out in a number of other countries; for example the Laser Association of Russia had a stand.
xi
Meetings Report Among some of exhibits on the various research institutions' stands was an integrated optical device for colour mixing, developed by the Institute of Applied Physics of the Friedrich-Schiller-University Jena. This is an optical strip waveguide in which light of different wavelengths from the whole visible region of the spectrum can be guided and electro-optically modulated simultaneously with single-mode operation. The University of Kassel exhibited some of its work on shearography, while the German Federal Institute for Materials Research and Testing had a stand describing its tasks and activities in optical measuring techniques, experimental stress analysis, pulsed laser micromachining, non-destructive testing, laser welding and laser spectroscopy. Away from the research and development institutions, there were many interesting new products and new developments on display, battling to gain visitors' attention. In fact, there was easily too many to be seen in any single day at the show, and far too many to be covered in this brief report. For example, Electrox used the show to launch a new Nd:YAG laser: the Ultima. This is claimed to have one of the highest beam qualities of any 0-400 W laser (see Opt Laser Technol 27, (4) page v) and, with pre-aligned optics with a 'V' rail assembly, is claimed to make misalignment virtually impossible. It also enables only a five-minute change-over of single fibres by non-skilled personnel. In addition, the laser has one of the smallest footprints of any 400 W laser, 1.1 m 2. Pumped by an exclusive laser diode bar technology, called FCbar, a new family of high-power diode pumped lasers, was introduced by Spectra-Physics. These fibre coupling laser diode bars, with > 90% efficiency, make it possible to create very high power diode pumped lasers while maintaining the high efficiency that is typical of end-pumped and mode matched designs. Pump powers are available up to 40 W.
Suitable ,fi)r eutting, welding and drilling, the Uhima laser launched by Electrox at LASER 95 has a beam quali O' that enables focusing to smaller spot diameters so providing higher power densities on the workpiece
xii
With the introduction 4ff the built-in halogen generator, HaloSafi~, and the new NovaTube technology from Lambda Physik, the excimer laser is said to he simpler to operate than a Nd: YA G laser, which requires Jrequent replacement qJi[lashlamps
The FCbar pump source is a field replaceable unit, which makes it possible to replace the laser diode in less than 20 minutes without optical re-alignment. Excimer laser operation has, so far, been associated with complex gas installation and high cost. However, with the introduction of the NovaTube, Lambda Physik claims to have virtually eliminated these concerns. The NovaTube technology is said to provide up to an order of magnitude longer gas lifetime, yielding over 1 billion pulses at 248 nm with one single gas fill. Optics cleaning was not necessary over this running period either. The laser used was a Lambda 2000 running in KrF, 248 nm at a stabilized average power of 50 W. Lambda Physik also introduced a laser made specifically to meet the needs of remote sensing and other narrow linewidth applications, from combustion analysis to 193 nm microlithography research. The COMPex 150 actually consists of two COMPex lasers configured as an oscillator amplifier. When used in the injection locked mode, the result is an excimer laser with high pulse energy (up to 450 m J), narrow linewidth ( < 3 pm) and low beam divergence ( < 0 . 2 mrad) output, which is tunable over the entire natural width of the laser gain curve. Two spectral sensors, developed by Carl Zeiss, allow the simultaneous detection of light wavelengths right into the deep ultraviolet range - an achievement that has previously been next to impossible with other compact spectrometers. The light is coupled into the spectrometer via a quartz fibre bundle cross-section converter built into an SMA connector. To avoid the absorption problems that occur with optical fibres below 220 nm, slit versions are in preparation that will not need any cross-section converter. A high-quality flat field grating (with a blaze wavelength approximately 220 nm) spectrally disperses the light and projects it onto a diode array. The entire spectrometer is permanently aligned Optics & Laser Technology Vol 27 No 5 1995
Meetings Report
The range of'miniature ,spectrometer modules from Curl Zeiss has been e.vtended into the ultraviolet region
and said to be maintenance flee. Both modules can simultaneously detect light wavelengths from 190 nm with an accuracy of 0.2 nm, with one sensor allowing spectral analysis to beyond 730 nm with a spectral resolution of 7 nm and the other detecting light up to 400 nm with a resolution of 3 nm. Carl Zeiss also presented an air-cooled argon/krypton mixed gas laser, the output power of which totals 10 mW line 1 in the three main colours (647 nm/red; 568 nm, .. yellow: and 488 nm/blue). In multiline applications, the L G K 7910 laser has a total output power of approximately 50 mW. For those visitors to the LASER who were still not convinced of the suitability of using lasers in their particular field, the Institute of Machine Tools and Industrial Management of the Technical University of Munich had a special exhibition demonstrating the integration of the laser into modern production struc-
The air-cooled ureon/krypmn mixed g a s laser" /rom Carl Zeis,~ u,ve,s u seale~gqlf technology design using internul mirrors. This ~h'sti~,n is heinE used /br the/irst time jor ar~on/kr.vpton lasers
Optics & Laser Technology Vol 27 No 5 1995
Optics & Laser Technology
tures through examples of specific applications and practical uses. The special exhibition, in the show's 'Manufacturing Technology' section, focused on several aspects of laser applications, illustrating them by practical demonstrations using different laser systems. A N d : Y A G laser cell was presented, which consisted of a 2 kW N d : Y A G laser and a 300 W N d : Y A G laser, each combined with an industrial robot as the optics handling device. While the 300 W laser was used for three-dimensional laser cutting of deep drawn sheet metal parts, the 2 kW laser robot demonstrated applications in three-dimensional welding of steel and aluminium parts. The Institute of Machine Tools and Industrial Management also explained its use of laser-assisted stereolithography for rapid prototyping. This enables, before production, a model of a p r o t o t y p e to be investigated such that the advantages and disadvantages of the design can be seen and measured. Laser assisted modelling was thus demonstrated to offer the possibility of reducing planning risk: it permits the recognition and correction of design flaws or shortcomings in product quality while still in the initial stages of product development. Overall, the LASER show was a big success and an enjoyable event to visit. The show is large, but it is also, like the city of Munich itself, very friendly and rewards spending time investigating it. The next L A S E R show will be held from 16 to 20 June 1997. Comparing the C L E O / Q E L S and L A S E R events has shown that despite some recent hard times, the industry is bouncing back to health with a flourish. New applications for optics and lasers are constantly being found and existing technologies refined and improved: and the defence industry does not have the tight hold it once had. Encouragingly, both C L E O / Q E L S and LASER had increased attendance, with some exhibitors at the L A S E R show claiming up to 50% more visitors and a m a r k e d increase in foreign contacts. After the international and political upheavals of recent years, the optics and laser industry looks set to benefit from i m p r o v e d global collaborations and, consequently, should be optimistic about the future. One final point, for the next LASER show - in 1997 - as an extra service from Messe Mtinchen G m b H , the event's organizers, it is intended that all1 visitors and exhibitors at the show will be able to use Munich's exceptionally good public transport free of charge. The exhibitor's pass, or admission ticket will act as a public transport ticket. This should cut costs for visitors and exhibitors who use Munich's public transport system, as well as relieving traffic congestion.
C L E O / Q E L S '96 2-7 June 1996. Anaheim. Cal(l'ornia. USA L A S E R 97 16-20 June 1997, Munich. Germany
xiii
Optics & Laser Technology
Industry shows flourish Earlier this year, the optics community had the chance to visit probably the largest conference and the largest exhibition in its calendar. Unfortunately, these t w o events were separated by a month and the small matter of the Atlantic Ocean. This year's CLEO/QELS meeting was held in Baltimore, USA fi-om 22-26 May, while the biennial LASER show was held in Munich, Germany from 19-23 June. Between them, the t w o events are good guides to the current state of optics and laser research and development as well as indicators of the industry's health. Comparing the t w o events also reveals the different emphases between the US and Europe.
CLEO/QELS
95 -
Baltimore,
USA
The 15th annual Conference on Lasers and ElectroOptics (CLEO) was held concurrently with the 5th Quantum Elcctronics and Laser Sciences conference (QELS), resulting in arguably the largest conference covering optics and lasers in the world. The event claimed to have more than 1200 refereed papers in over 20 topic areas. Unlike the Munich LASER show, at CLEO/QELS the emphasis is very definitely on the conference rather than the exhibition However, one of the problems with this is that, with up to eight sessions running in parallel, it can be difficult tinting things properly in order to see a desired presentation or to meet speakers. That apart, the s e s s i o n s were generally well organized, and certainly covered a wide range of subject areas. [lnlike, say, ten years ago, when a significant proportion of laser research was funded by the defence industry, and the papers submitted to conferences reflected this, these days the topic areas are much more
Baltimore harhour i s j u s t a short walk fronT the conference centre
widely defined with papers coming from many sources (although, naturally, there are still many papers emanating from military/defence establishments). For example, as well as conference sessions on the theory and current technology of various types of lasers and materials, there were also sessions on the therapeutic applications of lasers and electro-optics, optical sensors for medical applications, eye safe lasers, as well as new developments in biomedical microscopic imaging. On the Thursday of the week-long event, the "Joint s e s s i o n on emerging applications of fluorescence to biophysics and cellular imaging" too],: place. This consisted of a number of invited papers looking at the future potential of optical techniques to biolnedical applications. For example, Brian Herman et al. from the University of North Carolina looked at high-speed fluorescence microscopy, and described some biomedical applications of this new type of high-speed microscopy. By using optical microscopy and environmentally sensitive fluorescent probes, one can study the chemical and molecular dynamics of intact cells. R. Nitschke and K.R. Spring of the National Institutes off Health described the applications of electro-optic and laser technology to fluorescence microscopy. They have modified a video-rate confocal attachment to an inverted microscope to study better living cultured epithelial cells stained with fluorescent dyes. Their use of electro-optics enabled ewitation-ratio imaging and emission spectral scanning. To complement the biomedical conference s e s s i o n s , this year there was a 'biomedical passport four'. This was designed to highlight to exhibition visitors those companies with products and services directly related to biomedical applications. Among the new products was a system designed for laser acupuncture treatments. Launched by OZ Optics, the complete laser diode to fibre delivery system is compact and can be either battery operated or powered by an optional AC to DC converter. The delivery s y s t e m uses a 635 nm visible laser diode. Deliver),, systems with up to 12 mW of output power are available. Also introduced at CLEO/QELS was the "SapphiRe" optical fibre. Launched by Saphikon, these sapphire optical fibres can be used for applications in surgical erbium laser delivery - for example in surgical laser delivery, in ophthalmology, dentistry and general surgery - as well as in applications such as high-temperature thermometry, spectroscopy and other infrared sensing applications. These sapphire fibres have a transmission superior to quartz beyond 2.5 ~tm, so making them suitable for erbium:YAG laser delivery, in addition, sapphire is biocompatible, non-cytotoxic, inert and USP Class VI approved. With a high laser damage threshold and a high melting point (over 2000 C) sapphire offers a significant improvement over other infrared fibres. The
0030-3992/95/$10.00 :d: 1995 Elsevier Science. All right reserved Optics & Laser Technology Vol 27 No 5 1995
ix
Meetings Report 'SapphiRe' fibres have a wavelength range from 0.25 to 3.5 ~tm and a maximum attenuation at 2940 nm of 3 dB m d. However, the company has also demonstrated a loss below 1 dB m ] and, as fibre development proceeds, hopes to have these fibres available soon. Suitable for certain medical applications - such as contact surgery and prostate treatment - as well as for micro-welding, soldering and other materials processing applications, high-power diode laser systems were launched at CLEO/QELS by Opto Power Corporation. The OPC-B015-FCTS was claimed to be the only 15 W microprocessor-controlled diode laser system on the market. Pulse widths from 200 ~ts to CW, and repetition frequencies from single shot to 1 kHz can be set on the instrument's panel. Optics and laser techniques in biomedical applications may have a bright future, but one of the more traditional topics at CLEO/QELS meetings is that of laser fusion technology. This year, I. Okuda et al. from AIST, MITI, Japan described the status of the development of the super-ASHURA KrF 8 kJ, 12-beam laser. Its electronbeam-pumped main amplifier has already demonstrated a considerably enhanced electron-beam-deposition efficiency. J.J. Armstrong et al. from the University of Rochester described fabricating diffractive and refractive optical components for implementation on the 60-beam Omega laser (see Opt Laser Technol 27, page vi). Continuousmask photolithography and replication have been used in the fabrication of the large aperture ultraviolet components. As well as the continuing research into achieving power from fusion, lasers are also finding applications in many environmental areas. The CLEO/QELS session on atmospheric, space and ocean optics covered many such applications. For example, T.P. Grayson et al. from the US Air Force Wright Laboratories presented the design of a novel frequency-agile laser radar system. The system is based on an optical parametric oscillator (OPO) using periodically poled lithium niobate as the non-linear medium. Applications of this system include threedimensional remote hard-target imaging at eye-safe wavelengths, multispectral imaging and differentialabsorption spectroscopy. In the same session, Ryoichi Toriumi and colleagues, from the Tokyo Gas Company and Chiba University Japan, discussed the development of a differential-absorption lidar system based on a solidstate Ti:sapphire laser. The system was developed for nitrogen dioxide monitoring of diesel engine emissions. One of the special features of this year's CLEO/QELS was a birthday symposium in honour of Charles H Townes. Not only is 1995 the 35th anniversary of the first operating laser, but it also marks the 80th birthday of Townes, who invented the maser/laser principle and, in 1954, developed the first maser. This symposium was chaired by Nicholas Bloembergen and included contributions from people who have worked with Townes, including Arthur Schawlow and Boris Stoicheff. As well as the CLEO/QELS parallel sessions, there
x
were also three poster sessions, held on three consecutive lunchtimes. These proved popular, as always, as they enabled a far greater interaction between authors and visitors than was possible in the normal technical sessions. With over 5500 registered attendees at CLEO/QELS and several hundred companies in the exhibition hall, there was always much to see, and many products, both new and old, on display. Among the many new products was the Nd:YAG system from Big Sky Laser Technolo'gies, who claim their laser head is more than 55% smaller by volume than its closest competitor. The power supply/cooler unit is said to be 70% smaller. Designated the CFR200/MINICE, this laser can be used for traditional pulsed Nd:YAG applications but, because many of these applications are moving from the laboratory into the real world, this laser system has been designed for portability and to withstand the harsh environments associated with field or industrial use - the system is completely environmentally sealed to enable operation in almost any environment. In addition, the system has been designed as a 'plug-and-run' tool, to the extent that most users will not even have to align the system. Consequently, the system is suitable for OEM integration into instruments where the user simply wants the laser to perform its function and does not want to spend time doing numerous alignments and continually having to tweak the system. Applications include lidar, remote sensing, laser induced breakdown spectroscopy, laser induced fluorescence, laser ranging and laser induced ultrasound. Another laser launched at the meeting was the Series 142 CW single-frequency visible laser from Lightwave Electronics. This is a diode-pumped, compact, low-noise 532 nm laser for use in applications including interferometry and holography. As well as having the frequency stability, narrow linewidth, dual wavelength option, frequency scan and low-noise features of the company's 140 series, the 142 laser has higher power, a rounder beam, faster locking, lower cost and smaller size. With its OEM design, all control electronics are within the small laser head. The CW power levels available are 10, 20, 50, 100 and 200 mW. In addition to this, and a number of other new lasers - for example the series 210 Q-switched infrared laser, and the series 240 CW visible laser - Lightwave Electronics also announced an agreement with Sony Corporation, in Tokyo, for the joint development of diode-pumped solid-state ultraviolet lasers for applications in microlithography, optical disk mastering and microscopy. This ten-year agreement licenses Lightwave to use Sony's proprietary technology in nonlinear optical crystals to develop and commercialize CW and pulsed ultraviolet lasers and green laser devices. According to Bob Mortensen, president and founder of Lightwave Electronics, 'Lightwave's collaboration with Sony will accelerate the commercial development of ultraviolet applications in critical markets with significant growth
Optics & Laser Technology Vol 27 No 5 1995
Meetings Report potential'. The market for UV lasers is estimated to be $100 million and growing at 30% annually. Traditionally, the C L E O / Q E L S event alternates between Baltimore, Maryland, on the East coast of the USA and Anaheim, California on the West coast. Consequently, next year's meeting will be held in Anaheim from Sunday 2 June to Friday 7 June 1996.
L A S E R 95 -- M u n i c h , G e r m a n y
While the Baltimore conference centre is undoubtedly an excellent facility, with all the charms of its harbour-side location, it is hard to beat the facilities of the Munich LASER show. Not only quality of the trade fair halls themselves, but also the delights of the capital of Bavaria - from the exceptional and world-class museums and galleries (well over 30 of them), to the historic and attractive old centre with its numerous watering holes (where the beer is often drunk in litre glasses!). Unlike C L E O / Q E L S , the emphasis at the biennial LASER show is clearly on the exhibition: this year it filled seven huge halls. This is not, however, to downgrade the associated conferences, which not only included the LASER congress, but also the European Symposium on Optics for Environmental and Public Safety, and a ,joint German-Canadian workshop. The figures for the L A S E R event are quite staggering, with over 14 200 industry visitors from 61 countries, and over 700 exhibitors from 23 countries. In fact, this is an increase in exhibitors by about one third over the 1993 event and an increase of visitors by about 5%. Even the number of conference participants increased by 15%. This certainly places the LASER show as one of the world's largest optics and laser-based events and it shows with the imagination and effort that many of the exhibitors put into their stands.
The tw#l towers ,,?[the Frauenkirche, near to the Neues Rathaus. have become a symbol o[ Munich
Optics & Laser Technology Vol 27 No 5 1995
Compared with the previous L A S E R event, in 1993, the conference has also expanded. For example, the 1993 session on 'Lasers in Environmental Measuring' had effectively changed into the 'European Symposium on Optics for Environmental and Public Safety'. Likewise, the 1993 conference on 'Lasers in research' had 31 papers, while this year it had increased to 59 papers. It included sessions on lasers, lasers in chemistry and biology, quantum optics and ultrafast lasers, as well as a series of invited talks on lasers in research. Other conferences covered such topics as advanced solid-state lasers, optical measuring techniques, lasers in medicine, lasers in microstructure technology, and optical components and systems. As at the C L E O / Q E L S , there was a large contingent of Canadian companies, but at LASER, not only was there a section of the exhibition devoted to over 20 Canadian companies, there was also a joint GermanCanadian laser workshop. This was to provide an update of G e r m a n - C a n a d i a n collaborative projects in laser technology. In 1994, under the direction of the G e r m a n Ministry for Education, Science, Research and Technology (BMBF) a mission to Canada took place, which resulted in numerous possibilities for collaborative research between partners in the two countries. Topics covered in the workshop included (unsurprisingly) a number of success stories of Canadian-German cooperation, in the fields of diode-pumped N d : Y A G lasers, beam control of" industrial N d : Y A G lasers, fibre sensors and fibre lasers. Presentations were given, for example, describing the theoretical and experimental investigations into the supply of pulsed laser radiation to engineering materials, and also on the monitoring of penetration depth in laser beam welding. Other countries, as well as the Canadians, also had their own section of the exhibition. For example, in addition to all the large US companies exhibiting, there was also a group of US companies gathered together under the title ~Made in America'. Likewise:, a number of U K exhibitors could be found in Hall 3. Unlike C L E O / Q E L S , however, there were also a number of exhibitors from the Russian Federation. As well as all the exhibition stands bombarding visitors with information on all the (new and not-sonew) products on display - including three-dimensional video displays, high-power laser diodes and diodepumped solid-state lasers there were also many exhibitors who were universities and/or research institutions. Along with the congress, this helped give the event a research bias, rather than it being just another trade fair. Not only was there work from, naturally, a number of G e r m a n universities and research institutes (from both the former West and East Germanies) on display - for example, the various branches of the F r a u n h o f e r Institute -- but there was also a chance to see the R & D work being carried out in a number of other countries; for example the Laser Association of Russia had a stand.
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Meetings Report Among some of exhibits on the various research institutions' stands was an integrated optical device for colour mixing, developed by the Institute of Applied Physics of the Friedrich-Schiller-University Jena. This is an optical strip waveguide in which light of different wavelengths from the whole visible region of the spectrum can be guided and electro-optically modulated simultaneously with single-mode operation. The University of Kassel exhibited some of its work on shearography, while the German Federal Institute for Materials Research and Testing had a stand describing its tasks and activities in optical measuring techniques, experimental stress analysis, pulsed laser micromachining, non-destructive testing, laser welding and laser spectroscopy. Away from the research and development institutions, there were many interesting new products and new developments on display, battling to gain visitors' attention. In fact, there was easily too many to be seen in any single day at the show, and far too many to be covered in this brief report. For example, Electrox used the show to launch a new Nd:YAG laser: the Ultima. This is claimed to have one of the highest beam qualities of any 0-400 W laser (see Opt Laser Technol 27, (4) page v) and, with pre-aligned optics with a 'V' rail assembly, is claimed to make misalignment virtually impossible. It also enables only a five-minute change-over of single fibres by non-skilled personnel. In addition, the laser has one of the smallest footprints of any 400 W laser, 1.1 m 2. Pumped by an exclusive laser diode bar technology, called FCbar, a new family of high-power diode pumped lasers, was introduced by Spectra-Physics. These fibre coupling laser diode bars, with > 90% efficiency, make it possible to create very high power diode pumped lasers while maintaining the high efficiency that is typical of end-pumped and mode matched designs. Pump powers are available up to 40 W.
Suitable ,fi)r eutting, welding and drilling, the Uhima laser launched by Electrox at LASER 95 has a beam quali O' that enables focusing to smaller spot diameters so providing higher power densities on the workpiece
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With the introduction 4ff the built-in halogen generator, HaloSafi~, and the new NovaTube technology from Lambda Physik, the excimer laser is said to he simpler to operate than a Nd: YA G laser, which requires Jrequent replacement qJi[lashlamps
The FCbar pump source is a field replaceable unit, which makes it possible to replace the laser diode in less than 20 minutes without optical re-alignment. Excimer laser operation has, so far, been associated with complex gas installation and high cost. However, with the introduction of the NovaTube, Lambda Physik claims to have virtually eliminated these concerns. The NovaTube technology is said to provide up to an order of magnitude longer gas lifetime, yielding over 1 billion pulses at 248 nm with one single gas fill. Optics cleaning was not necessary over this running period either. The laser used was a Lambda 2000 running in KrF, 248 nm at a stabilized average power of 50 W. Lambda Physik also introduced a laser made specifically to meet the needs of remote sensing and other narrow linewidth applications, from combustion analysis to 193 nm microlithography research. The COMPex 150 actually consists of two COMPex lasers configured as an oscillator amplifier. When used in the injection locked mode, the result is an excimer laser with high pulse energy (up to 450 m J), narrow linewidth ( < 3 pm) and low beam divergence ( < 0 . 2 mrad) output, which is tunable over the entire natural width of the laser gain curve. Two spectral sensors, developed by Carl Zeiss, allow the simultaneous detection of light wavelengths right into the deep ultraviolet range - an achievement that has previously been next to impossible with other compact spectrometers. The light is coupled into the spectrometer via a quartz fibre bundle cross-section converter built into an SMA connector. To avoid the absorption problems that occur with optical fibres below 220 nm, slit versions are in preparation that will not need any cross-section converter. A high-quality flat field grating (with a blaze wavelength approximately 220 nm) spectrally disperses the light and projects it onto a diode array. The entire spectrometer is permanently aligned Optics & Laser Technology Vol 27 No 5 1995
Meetings Report
The range of'miniature ,spectrometer modules from Curl Zeiss has been e.vtended into the ultraviolet region
and said to be maintenance flee. Both modules can simultaneously detect light wavelengths from 190 nm with an accuracy of 0.2 nm, with one sensor allowing spectral analysis to beyond 730 nm with a spectral resolution of 7 nm and the other detecting light up to 400 nm with a resolution of 3 nm. Carl Zeiss also presented an air-cooled argon/krypton mixed gas laser, the output power of which totals 10 mW line 1 in the three main colours (647 nm/red; 568 nm, .. yellow: and 488 nm/blue). In multiline applications, the L G K 7910 laser has a total output power of approximately 50 mW. For those visitors to the LASER who were still not convinced of the suitability of using lasers in their particular field, the Institute of Machine Tools and Industrial Management of the Technical University of Munich had a special exhibition demonstrating the integration of the laser into modern production struc-
The air-cooled ureon/krypmn mixed g a s laser" /rom Carl Zeis,~ u,ve,s u seale~gqlf technology design using internul mirrors. This ~h'sti~,n is heinE used /br the/irst time jor ar~on/kr.vpton lasers
Optics & Laser Technology Vol 27 No 5 1995
Optics & Laser Technology
tures through examples of specific applications and practical uses. The special exhibition, in the show's 'Manufacturing Technology' section, focused on several aspects of laser applications, illustrating them by practical demonstrations using different laser systems. A N d : Y A G laser cell was presented, which consisted of a 2 kW N d : Y A G laser and a 300 W N d : Y A G laser, each combined with an industrial robot as the optics handling device. While the 300 W laser was used for three-dimensional laser cutting of deep drawn sheet metal parts, the 2 kW laser robot demonstrated applications in three-dimensional welding of steel and aluminium parts. The Institute of Machine Tools and Industrial Management also explained its use of laser-assisted stereolithography for rapid prototyping. This enables, before production, a model of a p r o t o t y p e to be investigated such that the advantages and disadvantages of the design can be seen and measured. Laser assisted modelling was thus demonstrated to offer the possibility of reducing planning risk: it permits the recognition and correction of design flaws or shortcomings in product quality while still in the initial stages of product development. Overall, the LASER show was a big success and an enjoyable event to visit. The show is large, but it is also, like the city of Munich itself, very friendly and rewards spending time investigating it. The next L A S E R show will be held from 16 to 20 June 1997. Comparing the C L E O / Q E L S and L A S E R events has shown that despite some recent hard times, the industry is bouncing back to health with a flourish. New applications for optics and lasers are constantly being found and existing technologies refined and improved: and the defence industry does not have the tight hold it once had. Encouragingly, both C L E O / Q E L S and LASER had increased attendance, with some exhibitors at the L A S E R show claiming up to 50% more visitors and a m a r k e d increase in foreign contacts. After the international and political upheavals of recent years, the optics and laser industry looks set to benefit from i m p r o v e d global collaborations and, consequently, should be optimistic about the future. One final point, for the next LASER show - in 1997 - as an extra service from Messe Mtinchen G m b H , the event's organizers, it is intended that all1 visitors and exhibitors at the show will be able to use Munich's exceptionally good public transport free of charge. The exhibitor's pass, or admission ticket will act as a public transport ticket. This should cut costs for visitors and exhibitors who use Munich's public transport system, as well as relieving traffic congestion.
C L E O / Q E L S '96 2-7 June 1996. Anaheim. Cal(l'ornia. USA L A S E R 97 16-20 June 1997, Munich. Germany
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