CHENNAI: Carrots cooked in alcohol may soon be a popular source of lasers. Researchers from the Indian Institute of Technology-Madras (IIT-M) have demonstrated the possibility of generating laser in an eco-friendly way, by using carrots as a lasing material, according to a statement issued by the institute.
The laser, generated through this technique, has immense potential in the field of bio-imaging.
Currently, the most common lasing materials, such as Indium-Gallium-Arsenic and Gallium-Nitrates, are manufactured using toxic chemical processes which are harmful to the environment. The new technique that the researchers have come up with uses just minimally processed carrots.“We fondly call this kitchen laser,” exclaimed Sivarama Krishnan, one of the guides of the research.
The research was undertaken by a team comprising Prof C Vijayan, Assistant Professor Sivarama Krishnan, and Venkata Siva Gummaluri, a PhD research scholar, from the Physics department of IIT-M.
The discovery itself was a result of the after-work-hours fun experiment, said Sivarama Krishnan. “We were pumping light through various organic materials and found that carrots have lasing properties. For example, we also tried orange juice and tomato juice,” he said. What set the humble carrot apart was the optically active bio-pigment called carotenoids present in the vegetable.
Although the fluorescence quantum yield of carotenoids is much less, compared to standard organic laser dyes, the vibrational spectra can be obtained even with extremely low concentrations of carotenoids, said Sivarama Krishnan. “We could easily increase the concentration of caretenoids on the surface of the carrots, by simply cooking it in alcohol. Then we pump light through a slice of the surface to get laser,” he said.
While the traditional polymers used were toxic and non-biodegradable, there has been search for more eco-friendly fluorescent polymers. In this search, the team looked at biological molecules as probable lasing sources.
Speaking about the importance of this research, Vijayan said, “There is now a move towards development of green, sustainable materials for various applications, including in photonics. The need for green photonic technologies is obvious in the current times where sustainability, bio-compatibility and degradability are of paramount importance.”
Carrots, in addition to having carotenoids, also have cellulose fibres that contribute to multiple scattering of photons and resultant optical amplification for Raman random lasing. The demonstration uses a process, first discovered by CV Raman, who won the Nobel Prize for Physics in 1930.
The researchers plan to advance their research to make the material more commercially viable. Currently, this material has potential as it is natural, bio-compatible, safe to handle and highly reliable.