Mankind has faced a multitude of healthcare related problems since time immemorial. But through studies and research, we have been able to fend off a majority of these health related threats. Over time, we have developed several methods to treat ourselves both invasive and non invasive. And although the success of these treatments depends on various factors, some methods are comparatively more risky than others, especially invasive methods. So, to add a safer alternative to the list of treatment options, researchers from the American institute of physics conducted an experiment and made some interesting new discoveries. 

The researchers created a new technology which involves the usage of tiny nanoparticles that can absorb light and turn it into localized heat sources. Within the medical field, the implications of this new technology could be huge. For example, photothermal therapy, a type of treatment that works on this principle, is a new but effective method to treat cancer. And since treatments such as these have already started gaining ground, developing more complex and efficient methods that run on the same principle could become a very achievable target. 

At the moment the main problem with this method is the lack of an option to measure temperatures in such systems. Control over this aspect is very crucial as the localized heating in these systems, if not handled carefully and accurately, could result in serious burns and tissue damage during the time of treatment. Multiple attempts, including the use of probes have already been made to come up with a fix for this problem, but none of them have been effective so far. 

But now, with the new research, this problem has finally been solved. This was made possible due to the usage of a light source known as terahertz radiation. In the study, experiments were carried out by immersing gold nanorods of various sizes in water in small cuvettes. These cuvettes were then illuminated by focusing a laser on a small spot within the cuvette.

It was observed that the immersed gold rods absorbed the laser light and converted it to heat which spread through the water by convection. Then, by scanning the cuvette with terahertz radiation, the researchers were able to generate a thermal image. Additionally, through the usage of a mathematical model they were also able to calculate the efficiency with which the gold rods converted the light into heat. 

The tiniest gold particles that were around the 10nm diameter range were seen to have the most conversion efficiency with over 90%. And since this matched with the readings from earlier reports on the nature of gold, the accuracy of the terahertz method was also confirmed. On the other hand, the largest rods that were in the range of 50nm had the highest molar heating range. And just like the other quantities, this one has its use as well,  and was even recently used to evaluate the use of nanoparticles in a biomedical setting. 

With these new found abilities, the researchers combined the measurements of temperature in time and thermal images in space at terahertz frequencies to develop a safe and easy method for characterising these nanoparticles. As mentioned earlier, this could have a massive impact within the healthcare sector. So with more time and studies, we could potentially have a better alternative to invasive methods and make further progress in the biomedical field.