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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

#Women’sMonth: Who am I? Questions of identity among Rwandan rape survivors
2017-08-03

 Description: Michelle Nöthling, Questions of identity among Rwandan rape survivors Tags: Michelle Nöthling, Questions of identity among Rwandan rape survivors 

Michelle Nöthling, master’s degree student
in the Centre for Trauma, Forgiveness, and
Reconciliation Studies at the UFS.
Photo: Eugene Seegers

From 7 April to 15 July 1994, a mass genocide swept through Rwanda after years of Belgian colonial rule that divided the country along ethnic lines. Rape was also used as part of a political strategy to torture and humiliate mainly Tutsi women, and as a means of spreading HIV.

Individual focus
Why is it important to listen to what these rape survivors have to say? Michelle Nöthling, a master’s student in the UFS Centre for Trauma, Forgiveness, and Reconciliation Studies, responds, “We speak of groups – refugees, foreigners, and the like – yet we tend to forget the individuals and the lasting impact trauma has had on each person.”

Narrative exploration
Michelle maintains that we are the product of the narratives around us; things like – how to be a woman, how to dress, speak, or treat others. Her research delves into how these rape survivors see themselves, how they narrate their lives. She also investigates power relations based on gender; for example, how language can be used as a divisive tool.

Rwandan backdrop
In Rwanda, gender roles are deeply entrenched. Traditionally, a ‘girl’ remains such while she is a virgin. Her transition into womanhood is usually marked by marriage and followed by motherhood. But rape disrupts this structure, leading to an identity crisis as these girls are catapulted into motherhood with an unplanned child resulting from a traumatic event.

“We are the product of
the narratives around us.”

Reaching their mid-teens, the children, too, started asking questions about identity or paternity. For those mothers who were finally able to open up to their children, the experience has been mostly liberating – often leading to a closer relationship between parent and child. Michelle intends to interrogate how such significant moments shape the way these women perceive themselves. Research tends to portray these survivors solely as mothers of rape-born children. Michelle, however, seeks to examine their identities more deeply.

“These survivors still bear the heavy burden of being marginalised, stigmatised, and severely humiliated. Despite this, they have developed their own communities of belonging; people with whom they connect, to whom they relate, and to whom they are not ashamed to tell their experiences,” she said.

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