John H. Marsh
University of Glasgow and Intense Photonics
Intense Photonics Ltd., 4 Stanley Blvd, Hamilton Intl. Technology Park, High Blantyre G72 OBN, Scotland, UK
johnmarsh@intensephotonics.com

Abstract: Scotland has a long history in optics, led by figures including Thomson (Lord Kelvin), Brewster, Maxwell and Bell, and was a centre in the development of photography. Recent innovations include optics in telecommunications, gravitational wave detectors and astronomy.

Introduction
The LEOS field of interest is broad, encompassing ‘lasers, optical devices, optical fibres, and associated lightwave technology and their applications in systems and subsystems in which quantum electronic devices are key elements’. Arguably, the field of optical sciences is broader still, as it would place an equal emphasis on the wave, as opposed to the quantum, nature of light. This paper describes some of the major developments in optical sciences in Scotland from the 17th century through to the present.

Historical Development

Fig. 1: Accomplishments and picture of James Gregory. An illustration of his office is also shown.

Despite being a small country (current population —5million), Scotland has made significant contributions to the field. The country has four ancient Universities: St Andrews (1411), Glasgow (1451), Aberdeen (1495) and Edinburgh (1583) and early fundamental work centred on these institutions.
James Gregory (1638-1675), shown in Fig. 1, arguably the greatest scientist associated with the University of St. Andrews, was appointed to the newly created Chair of Mathematics in 1669. Gregory was the first to publish a proof of the fundamental theorem of calculus and the first to discover Taylor’s theorem. Isaac Newton, at Cambridge frequently relied upon Gregory’s work. In 1661 he invented a type of reflecting telescope — the ‘Gregorian’ telescope. He also discovered the diffraction grating using the feather of a bird. In 1674 he accepted an invitation to become a professor at Edinburgh University, but died the following year, aged 37.

Fig. 2: Accomplishments and picture of David Brewster. Two examples of his instruments are shown.

Sir David Brewster (1781-1868), shown in Fig. 2, made many important contributions to the field, notably experimental investigations of the polarization, reflection and absorption of light. Although responsible for more than a hundred patents, the profits from his most famous invention, the kaleidoscope, were denied him due to a faulty patent application. From 1838 on he was Principal, first of a college of St Andrews, and then of the University of Edinburgh. Despite his discoveries, he became one of the last and most contentious opponents of the wave theory of light, leading the final struggles in the 1850’s. He was a close friend of Henry Talbot, the Englishman credited with the invention of photography, and Talbot lived in Edinburgh from 1855 -1867. The interaction between these scientists and a wider group led to developments in the use of photography. The Edinburgh Photographic Society was instituted in 1861 and still exists.

Fig. 3: Accomplishments and picture of William Thomson, Lord Kelvin.

William Thomson (Lord Kelvin), shown in Fig. 3, is one of the pre-eminent scientists of the 19th century. He attended Glasgow University from the age of 10, commencing university level work at the age of 14. In 1841 Thomson entered Cambridge, graduating in mathematics in 1845. In 1846 he was elected to the Chair of Natural Philosophy at Glasgow. Although most famous for his contributions to thermodynamics, his work on heat led him to develop a dynamical theory for electricity and magnetism. He was the first to treat Faraday’s conception of lines of force mathematically. His work on electricity and magnetism is important for it led James Clerk Maxwell to develop the theory of electromagnetism. Thomson achieved his greatest fame through a telecommunications project: the laying of a submarine cable between Ireland and Newfoundland on which he started work in 1854. He played several roles, being on the board of directors and also being an advisor on theoretical electrical matters.

Fig. 4: Accomplishments and picture of James Clerk Maxwell.

James Clerk Maxwell, born in 1831 and shown in Fig. 4, is regarded as one of the world’s greatest physicists. He was born in Edinburgh as shown in Fig. 5, educated at Edinburgh Academy, and attended the Universities of Edinburgh and Cambridge. Maxwell’s theory united electricity and magnetism into the concept of the electro-magnetic field. He died relatively young, and some of his theories were only conclusívely proved long afterwards. His unification remains one of the greatest landmarks in the whole of science, paving the way for Einstein’s special theory of relativity and quantum theory.

Fig. 5: Maxwell's house (his birthplace).

John Kerr (1824-1907) was an almost exact contemporary of William Thomson, and they were close friends. His first publication, on what is now known as the Kerr electro-optic effect, came ín 1875. This effect, for which Faraday had searched 40 years earlier, is the rotation of the plane of polarisation of light in passing through an optical medium across which an electric potentíal is applied. An original Kerr cell is shown in Fig. 6. Nearly a century later, the advent of the laser allowed the same process to be observed usíng the AC electric field of the light itself. The AC Kerr effect is an essential ingredient for optical solitons, solitons themselves first being observed in water waves on a canal in 1844 by John Scott Russell (1808-1882) as shown in Fig. 7. In 1876 Kerr also published details of the magneto-optic effect. The magnetic effect showed that a rotation of the plane of polarisation of light occurred on reflection from the polished pole of a magnet.

Fig. 6: Accomplishments of John Kerr. His experimental setup for the Kerr Cell is shown.

Commercial Developments

Fig. 7: Accomplishments and picture of John Scott Russell. A photograph of a solition on the Scott Russel Aqueduct near Heriot Watt University is also shown.

These scientific developments were accompanied by considerable industrial activity. Two areas of particular note lie in telecommunications and television. Thompson’s contributions to the first transatlantic cable have already been mentioned. Alexander Graham Bell (1847-1922), shown in Fig. 8, is best known for his invention of the telephone, which was itself a development of his techniques for teaching speech to the deaf. After inventing the telephone, Bell continued his experiments in communication, inventing the photophone: transmission of sound on a beam of light, the precursor of fibre-optic communications. John Logie Baird (1888 -1946), shown in Fig. 9, studied engineering at the Royal Technical College (now the University of Strathclyde) and Glasgow University. His attention was directed to television in 1923 and three years later he demonstrated a mechanical scanning system based on Nipkow’s disk. From 1929 to 1935, the BBC used the Baird mechanical television system; in the last part of this period, the electronic system was developed that was to replace mechanical television completely. Baird, however, went on to demonstrate the first colour, high definition and stereo televisions and succeeded in recording video signals on disks.

Fig. 8: Accomplishments and picture of Alexander Graham Bell. A diagram of the photophone is also shown.

Fig. 9: Accomplishments and picture of John Logie Baird. Television and an early images are also shown.

Fig. 10: Diagram of professional societies and links in Scotland.

Fig. 11: Detection of Gravitational waves with advance interferometry.

Fig. 12: Direct spectroscopic detection of extra-solar planets.

Present Day
Currently 12 out of Scotland’s 13 universities have some specialisation in optoelectronics. Throughout the 1980s and 1990s, a strong optoelectronics research cluster developed, principally based in the Universities of Edinburgh, Glasgow, Heriot-Watt, St Andrews and Strathclyde but with significant activity elsewhere. A diagram of the professional societies and links are shown in Fig. 10. Several groups are internationally recognised as holding a position of excellence in optoelectronics technology, continuing the long tradition of scientific endeavour amd invention cited above. Scottish universities also account for around half of all United Kingdom graduates in optoelectronics. Areas of notable strength include: Semiconductor materials; Optoelectronic devices; Photonic integrated circuits; Optical information processing; Diode pumped solid state lasers; Carbon dioxide lasers; Optical computing; Optical sensors; Semiconductor lasers; Optical component performance monitoring; Thin filmcoatings. In addition, optics in its most general sense continues to be developed and applied to fundamental science. Examples include ultra-stable interferometers for detecting gravitational waves (Glasgow), as shown in Fig. 11, and spectrometry for discovering planets outside the solar systern (St Andrews), as shown in Fig. 12.
In the 1980s and 1990s, major companies also had a Scottish presence, with the largest being parts of what are now BAE SYSTEMS and Thales Optronics. However, links between the universities and industry, at least in the area of research, were relatively weak. Several factors have caused this picture to change in the past ten years. Firstly, there has been recognition at government level that university research should be exploited much more vigorously and, as a result, Scottish Enterprise has increased its emphasis on high-technology start-up companies and on the optoelectronics sector. Its initiatives include the Scottish Optoelectronics Association, the creation of an optoelectronics foundry, Compound Semiconductor Technologies, and promotion of an optoelectronics economic cluster. Secondly, increased access to higher education coupled with a steady erosion of government funding has forced universities to look for other funding sources, with commercial exploitation of their research being an obvious route. A third factor has been the world-wide explosion of activity in optoelectronics start-up companies, largely driven in recent years by the communications sector.
Optoelectronics is now playing an increasing role in the Scottish economy: the industry is currently worth $1billion and is expected to grow to $2.4billion by 2005 and to $8.8billion by 2010. In addition to the economic benefits brought by the older established companies and by research activity in the universities, there is a range of SMEs encompassing one-person consultancies through to companies with major manufacturing ambitions. Examples of recent start-ups in the communications field alone include Intense Photonics, Kamelian, Kymata (now Alcatel Optronics) and Terahertz Photonics. Although the communications industry is currently in retrenchment, it can be seen that communications has been a recurring background theme since at least 1854, and will certainly return to being a driver of optical technology in the near future. In addition optical technology is expanding rapidly into other fields (not least in displays) and will be of increasing importance in both scientific and economic contexts in the future.