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18 April 2022 | Story Leonie Bolleurs | Photo Stephen Collett
Prof Ted Kroon
Prof Ted Kroon from the Department of Physics recently delivered his inaugural lecture on the topic What’s the use of a rainbow on the UFS Bloemfontein Campus.

“A rainbow is a natural phenomenon, the result of the refraction and reflection of the sun’s rays in drops of rain. As far as mankind is concerned, it’s a perfectly useless object and won’t make anyone money. Yet the poet who said, My heart leaps up when I behold a rainbow in the sky, only put into word the feeling of wonder and excitement we all have when we see a rainbow.”

“Every day I see a rainbow in my work; I do not need to wait to see one in the sky,” says Prof Ted Kroon, Professor in the Department of Physics at the University of the Free State (UFS), who used this phenomenon to introduce the topic of his inaugural lecture: What’s the use of a rainbow. 

“Far from being only a colourful spectacle with no practical value, rainbows are useful – and lead to useful things,” he believes. 

According to Prof Kroon, one can find examples of real rainbows and rainbow analogies used not only in everyday life, but also in physics. “Besides it being familiar devices in literature, culture, and even marketing, studies of rainbows can yield practical engineering information and may even help us to find new habitable planets,” he says.

Inspired by the many uses of a rainbow

In his lecture, he discussed the basic features of natural rainbows and how they come about. He also explored how the rainbow gives meaning to colour, and how this relates to the temperature of objects. He looked at an array of instances where the rainbow is used; from depicting the life of a star to indicating that we are sick (a thermometer) or when we need to refill a gas cylinder.
Moreover, Prof Kroon pointed out that rainbows are used in computer chips, stress identification, and to transmit internet data through underwater cables of glass fibre. He also referred to how the rainbow was harnessed as an engineering tool to measure refractive index and characterise fine droplet sprays used in industry. 

He continues, “Remarkably, the science developed to understand the natural rainbow can be redirected and applied to the optical properties of metallic nanoparticles, allowing the development of nanotechnology. Knowing how the natural rainbow works and its limitations, better systems have been developed to produce rainbows. Such rainbows have been used to discover new elements and to determine the age of the universe.”

As a member of an international community of phosphor researchers who are privileged to work with rainbows every day, he has used them to study the light-emitting properties of materials doped with bismuth. With this project – an initiative with the African Laser Centre taking place between 2016 and 2021 – he collaborated with the University of Khartoum in Sudan and trained a number of its postgraduate students. “My role included the guidance of students and the measurement and interpretation of the light-emitting properties of the materials. Our research during this time, considering more than a dozen materials, was summarised in 34 scientific publications that contributed to a greater understanding of bismuth ions as light-emitting materials,” he explains. 

Developing new materials, efficient in emitting blue light

He has been developing luminescent materials since 2006, primarily for general lighting (fluorescent tubes and LEDs) and displays (television, computer, and cellphone screens), as well as niche applications in medical and forensic science. 

As part of his current research, he is examining the effect of plasmonic metal nanoparticles on phosphor light emission. He is also exploring materials that absorb infrared light but emit visible light. “For this, I would like to consider the long-term stability of such materials and develop new materials that are more efficient in emitting particularly blue light,” he says. 

Prof Kroon holds a C2 rating from the National Research Foundation and has published more than 150 articles and book chapters, obtaining a Scopus h-index of 26.

News Archive

UFS Alumni honours five Kovsie Alumni
2009-08-26

 

 
Prof. André Venter and Prof. Johan Grobbelaar
Photo: Supplied

The sought-after Kovsie Alumni Awards, which are awarded to alumni of the University of the Free State annually, will be presented to five Kovsie alumni at a gala award dinner on Friday, 4 September 2009.

UFS Alumni nominated Mr Gert Grobler as the 2008/09 Kovsie Alumnus of the Year. Dr. Gert Marincowitz and Sekoati Tsubane (Kabelo in 7de Laan) will receive the Kovsie Alumni Cum Laude Award. Prof. Johan Grobbelaar, Senior Professor at the Department of Plant Sciences and Prof. André Venter, Chief Specialist at Paediatrics and Child Health, will both receive the Kovsie Alumni National Executive Award. These awards are presented annually to honour alumni for their excellent achievements and contributions towards the UFS.

The Kovsie Alumnus of the Year Award is presented to a Kovsie alumnus with outstanding achievements at national and international level. Mr Grobler receives this award for his role as ambassador for South Africa in Japan and the significant role that he played in initiating various structures and bilateral mechanisms to improve South Africa’s relations with various countries actively. His expertise, knowledge and passion for the diplomatic service and direct mediation and involvement in the establishment of various projects abroad are evidence of his dedication.

Dr. Marincowitz, who has also been honoured as RUDASA’s Rural Physician of the Year, receives the Kovsie Alumni Cum Laude Award for his contribution to the promotion of primary health care in rural areas in Limpopo and for his role in sensitisation towards HIV care in these communities. The Cum Laude Award is given to an alumnus for outstanding service or achievement at local, national or international level in his/her specific professional field.

With his portrayal of the character Kabelo Padi in the Afrikaans soap 7de Laan, Mr Tsubane has distinguished himself in a highly competitive market. His impressive presence in portraying this character makes him a factor to be reckoned with in the world of entertainment.

Prof. Grobbelaar is honoured for his contributions, which put the UFS in the forefront, especially in the field of research, leading research expeditions to Marion Island and research in the Amazon, as well as the establishment of the first commercial algae-biotechnological plant in Africa at Muzina. His phenomenal leadership role in salary negotiations, his transparent and inclusive management style and the incredible way in which he empowers people to fulfil their tasks at the UFS also makes him a worthy recipient of the award. Under his leadership, UVPERSU has grown into the majority and representative union on campus.

Prof. Venter is also honoured for his outstanding service delivery to the UFS over the years and the exceptional way in which he has developed the Department of Paediatrics and Child Health to be one of the prestigious departments in the country. In the field of paediatric neuro-development, he dramatically improved the lives of children with attention-deficit hyperactivity disorder. He has also played a major role in generating money to acquire equipment to improve intensive-care facilities in the paediatric unit in particular. He has been honoured by the International Biographical Centre in Cambridge as one of the Great Lives of the 21st Century and is a finalist for the Bloemfontein of the Year 2009 award.

Everyone is welcome to attend the Kovsie Alumni Gala Award Dinner that will be held in the Reitz Hall of the UFS Centenary Complex. Various talented Kovsies will appear as guest artists. The cost of R120 per person includes a three-course meal. If you are interested in attending the dinner, contact Annanda Calitz at 051 401 3382 or ficka.stg@ufs.ac.za.

Media release:
Lacea Loader
Deputy Director: Media Liaison
Tel: 051 401 2584
Cell: 083 645 2454
E-mail: loaderl.stg@ufs.ac.za  
26 August 2009

 

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