Interview with The Independent

Laser application can solve problems like arsenic

Interview with Dr. S. Rafi Ahmad

The Independent: Please tell us about your specialised field of research?

Dr. Rafi: My specialisation field is laser spectroscopy. Spectroscopy is essentially a process of ‘Un-Weaving the Rainbow’ i.e. the separation and analysis of the colour, scientifically measured in terms of a parameter called the wavelength. The intensity of a light beam at a particular colour bears the signature of the source. The more detailed one analyses the colour of the light, more specific becomes the fingerprint of the source. The question is what is a source? Basically whatever you see is a source of light, it could be a secondary, such as a reflected or scattered light or the direct light such as that from the sun or a flame. One has to bear in mind that light is created from the inherent or induced energy in the atoms and molecules of matter.

The Independent: Do you have any basic work on the applications of laser and optical spectroscopy?

Dr. Rafi: Spectroscopy has been used over centuries to study the properties of matter and also for an understanding of the fundamental interaction processes between light, or generally speaking the electromagnetic wave, and the matter. Introduction of lasers in spectroscopy during the last 3 decades and the great advancement in electro-optic technologies have now given rise to a ‘brave new world’ – where, our understanding of the world and the nature of mater and energy have advanced to the limit and esoteric applications, in a widely diverse fields, have come to commercial realisation. My special interests are in the applications such spectroscopic techniques for remote and real-time monitoring of pollution both in water and air environments, optical tracer technology for material identification for sorting or authentication, early diagnosis of. malignancy in biological tissues etc. All these are underpinned by fundamental research through Ph D studentship programmes.

The Independent: How many laser applications are been using now for the benefit of people?

Dr. Rafi: When laser was invented, it was hailed as a ‘tool looking for application’. But now, laser is everywhere, at home in your CD players or in your computer printer, in industry, in battlefield, in doctor’s surgery, in offices. When laser was applied to spectroscopy, I coined a phrase, “Laser spectroscopy is a solution looking for problems”. The scope for laser spectroscopy application is practically limited only by man’s ingenuity and desire to invest resources for research and development.

One aspect of laser application which might be of interest to Bangladesh is my commitment to a European Network called COST Action G7 – Conservation of cultural heritage by laser. Almost 4 years ago I initiated the network with the active collaboration of a Romanian scientist involved in research on this topic. Eventually we made a network of 27 partners from 20 odd European countries (both east and west). There are 3 working groups and I am the co-ordinator of the WG3- monitoring of artwork environment. The EU currently funds the network. We meet every 6 months and exchange results and ideas through workshops. Laser is now very effectively used for non-destructive cleaning of artwork and objects of antiquity including stonework. Old objects such as coins, fabrics, stone statues etc, can easily be restored to their original glory by using pulsed Nd-YAG laser. We do some scouting research on the radiation dose required for each object type and other aspects of laser cleaning. If the artwork restorer, curators or museum authorities are interested in this technology I am happy to advise.

The Independent: What was your research on tracer technology?

Dr. Rafi: Following some basic research by one of my Ph.D students on the use of laser induced fluorescence and Raman spectroscopy of polymers for molecular characterisation, I decided to apply the results for commercial application. A consortium of six European research centres and industries (including my institution) was established and R&D was conducted jointly with funding from the EU commission. We have researched on the fluorescence properties of a host of commercial dyes (tracers) in various polymer matrices and studied the effects of artificial weathering, temperature, environment etc. Following the study we designed and developed a sensor system, which was able to detect fluorescence signals from different plastics, traced with a binary combination of tracers, at a very fast rate. The system was tested on an industrial plastic sorting system operating at an industrial site on the south coast of England. The technology and the concept are being commercialized for a variety of applications through joint venture R&D with a French company called Tracing Technology Ltd (Patent pending)

The Independent: Can we know about your research on environmental pollution monitoring?

Dr. Rafi: My research on the interaction of lasers with water-borne pollutants, both organic and inorganic, has prompted me to apply laser spectroscopy for real time monitoring of such pollutant species for process/quality control in water processing or water-intensive industries (for water recycling). The idea is very simple. The dissolved organic species in waste or surface water give out fluorescence signature. The research was to identify laser wavelength to obtain the specific signature, which corresponds to the dissolved organic matter, and correlate optical signal intensity with the concentration of these species. A prototype instrument has been developed in my laboratory under industrial/DTI sponsorship and is now undergoing industrial tests and validation. In addition to that, I am now conducting research to develop a sensor system for monitoring heavy metals in water by a technique called laser-induced breakdown spectroscopy (LIBS). This is essentially an atomic spectroscopy method, only that we use high-power laser as a hammer for ionisation/atomisation of metalloid species. The project is funded by EU and has 12 industrial partners of which I (my Centre) am the only research technology and demonstration (RTD) provider.

The Independent: Can you explain safety aspects of laser research?

Dr. Rafi: Laser light is an intense beam of practically non-divergent monochromatic light. The power density in a laser beam of moderate power could be much higher than that from the sun. Because it is monochromatic and non-divergent it gets tightly focused on to the retina of the eye, thus providing exceedingly high power density to damage the eye. Therefore, we need to take adequate precautions while we use lasers. There are well-established code of conduct and safety protocols, which we must obey. However, for practical applications we tend to use low-power lasers and sometime we use thermal sources such as Hg source, and make it monochromatic and non-divergent by filter and collimating optics.

The Independent: Your research on jute modification is currently under review by the Bangladesh Jute Research Organisation for commercial exploitation. Can you tell us about your research on jute modification?

Dr. Rafi: My expertise is not directly related to research on the chemical and radio-chemical modification of jute. In my early career I did extensive research on the modification and characterization of polymers using both lasers and high-energy gamma radiation. In early 90’s there was a call for proposal within the European Union’s website (cordis) under INCO-DC (International Cooperation with developing Countries) on research on materials/product modification, I took the opportunity and applied for a grant with the Physics department in Dhaka and the Bangladesh atomic Energy commission as research partners. The main goal was technology transfer, major research being conducted at my laboratories here. I recruited a polymer scientist and brought a student from Bangladesh to conduct research for his Ph.D thesis. There had been several visits to my laboratory by scientists from Dhaka University and the Atomic Energy Commission for research collaborations. We also had funds to purchase some major test equipment for Dhaka University. The 3-year research project was successfully concluded but the results are still to be exploited through application-oriented R&D. In my recent visit to Bangladesh I met some old colleagues (Dr Abdullah) at the Jute Diversification promotion Centre, and also I am in contact with people (Dr. Latifa Binte Lutfar) at the International Jute Study Group and are in consultation on the way ahead for the implementation of our past research results and formulating new research on this topic.

The Independent: What are the beneficial sides of your researches – particularly to Bangladesh?

Dr. Rafi: My research outcome will surely benefit a wider world community through the development of cost-effective sensor system for on-line quality/and process control. Since the researches are funded by either the UK government/industry or the European commission, the intellectual property right will belong to either my institution (Cranfield University) or to the sponsoring industrial partners. Therefore, they will be benefited financially. I am trying to implement an optical technology for monitoring heavy metal and my emphasis on the detection of arsenic. This I do with the knowledge that Bangladesh has an acute problem with arsenic poisoning and there does not seem to have any cost-effective monitoring system. I hasten to add that the commercial viability of such a system is yet to be validated through further research. I am interested in collaborating with scientists in Bangladesh for any applied research based on laser and applied spectroscopy. I have also research interest in using laser spectroscopy for early diagnosis of malignancy and also in lasers Lithotripsy (breaking down of kidney stone). I have discussed about the prospect of a joint research programme with the head of the Urology department at the Dhaka medical college.