ANALYSIS AND OPINION REMEMBERING PROFESSOR BRYAN TOZER
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remember the hologram of used nuclear fuel rods which used to hang in our lounge in our New Forest home, despite the protests of my mother. In the 1970s and 1980s
the electricity-generating industry was becoming aware of the problem of harmful gas emissions from coal and oil-fired stations, notably nitrogen dioxide, ozone and sulphur dioxide. The high chimney stacks of power stations and prevailing south westerly winds in the UK meant that the pollutants were carried across international borders. Sulphur dioxide was of particular interest because it was known to cause ‘acid rain’, and SO2
emissions from the
CEGB were blamed for causing deforestation in Scandinavia. A means of quantifying emissions from power stations was required, so MEL developed a lidar technique for the measurement of SO2 in power station plumes. This technique involved the use of a
“[Professor Tozer] became the laser safety officer for the UK electricity industry and, in the days before personal computers, developed algorithms for classifying lasers and for assessing their safety”
frequency doubled tunable dye laser, and was able to detect concentrations down to 10ppb at a range of 2km. Nowadays it is well
understood that lasers can be hazardous, but in the early days this was not so well known. Bryan told me that one day, while watching a q-switched ND:YAG laser producing a spark in mid- air, he thought ‘what would happen if this beam was to hit someone in the eye?’ He became the laser safety officer (LSO) for the UK electricity industry and, in the days before personal computers, developed algorithms for classifying lasers and for assessing their safety. As LSO for the UK electricity industry, he was appointed
12 Electro Optics November 2017 Professor Tozer and colleagues developed a lidar technique for quantifying emissions from power stations
to the BSI EPL/76 committee, which was responsible for laser safety standards in the UK, and chaired this committee from 1985 until 2008. With his background in applied physics research and electrical engineering, where complex physics is used to solve engineering problems in the real world, I know Bryan didn’t set out to become a leading expert in laser safety – he didn’t regard it as a real subject. Nonetheless, I think the diligence with which he approached his work just led him in that direction. As chairmen of the BSI committee, he naturally attended the European laser safety committee (Cenelec TC 76) to represent UK interests and became chairman of that as well, from 1993 to 2008. He also sat on the International Electrotechnical Commission (IEC) Laser Safety committee (IEC TC 76) throughout this time. These committees governed the Laser Safety Standards, BS EN 60825- 1 – Safety of Laser Products, Equipment Classification and Requirements, EN 60825-1 and IEC 60825-1, respectively, as well as the entire suite of 60825-x standards. For a similar period of time he chaired
working group 5 of IEC TC 76, which governed the formation and evolution of IEC 60825- 2 – Safety of Laser Products and Safety of Optical Fibre Communication Systems. At one time there was talk of him becoming chairman of IEC TC 76, but I think a clean sweep of international and national committees would have been too much to deal with! After taking early retirement
from the CEGB in 1987, Bryan took up a position as a visiting Professor at City University London and also founded his company Lasermet with Dr Bill Fagan. Originally it was intended that the firm would focus on laser measuring systems similar to those that Bryan had been developing at the CEGB. However, this failed to take off and after I joined the company in 1994, we increasingly focused on utilising his growing international reputation in the field of laser safety. Initially, this was focused on training and consulting, which later developed into the founding of a UKAS-accredited testing laboratory for product testing to EN 60825-1 and associated standards, and then expanding into laser safety products and finally complete safety systems.
During the 1990s and 2000s
there was a massive expansion in the applications and use of lasers in the fields of science, medicine, cosmetics, military and manufacturing. And wherever lasers were used, Bryan would get involved to assess the hazards and help the manufacturers and users comply with the standards, which meant that he gained a tremendously broad knowledge of the laser industry. From the rather unique problem of 532nm lasers that are scanned on to the retina to produce a high-resolution image for ophthalmology, to 808nm lasers used for cosmetic hair removal, through 1,064nm military range finders with a 20km NOHD and 10kW fibre lasers used for cladding, welding and hardening applications. By the time that ill health
forced him to withdraw from active participation in the business, my father had seen the development of laser technology from its inception in the early 1960s to the vast array of lasers and laser applications now available, over 50 years. EO
Further information
1 B A Tozer, 1975. Physics in Technology 6 251
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