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Physicist Traps Light and Wins Canada’s Highest Honor

November 19, 2021

The idea of trapping light, may be hard to imagine, but not for Sajeev John who actually managed to achieve this mind-boggling feat. John created the Photonic Band Gap (PBG) which involves trapping photons which are then controlled by an “optical microchip, analogous to how electrons are controlled in a semiconductor.”1, 2

John’s PBG materials were a long time in the making. He grew up with Ottawa, Canada with his physicist father before attending Harvard University where he earned a PhD. After a supervisor asked “'Why don't you do something different from what everyone else is doing?'",  John began to think of containing wavelengths beginning with soundwaves and finally landing on light once he realized how important this task could be.1 As a theoretical physicist, John was able to perform calculations based on his theory of what would work to trap light, then he brought together a team of experts to build the PBG materials.1

For the PBG, John received the Natural Sciences and Engineering Research Council of Canada’s (NSERC) $1 million Gerhard Herzberg Canada Gold Medal. This medal is the highest honor given out by NSERC and is only bestowed upon those who demonstrate “sustained excellence” and “overall influence”.2

According to a NSERC press release, John’s invention “is a highly consequential breakthrough in the fundamental science of light-matter interactions” because it “allow[s] confinement of photons to a microscopic region with the size of the wavelength of light…As a result, it may be possible to process information optically rather than electronically, enabling a supercomputing technology more stable and scalable than quantum computers.”2

The PBG has already been implemented to destroy tumors during laser surgery allowing surgeons to shine light through a hollow cable instead of the traditional methods which involve serious incisions and are also used in state-of-the-art ‘“lab-on-chip” optical sensors” which are used to detect biomolecules that indicate various diseases, speeding up diagnoses.1, 2  Outside of the medical field, John has used his technology when producing solar cells in an effort to create sustainable and eco-friendly power.2

"The Herzberg Canada Gold Medal will be very useful in attracting other aspiring young scientists to work on my team and be a part of this effort," said John in an interview with CBC. "So quite a lot of it is going to be used to, you know, to bring in good PhD students, postdocs, visiting scientists — people that can work on the project."1

John has won many other awards for his work including being appointed as an officer of the Order of Canada and a Canada Council Killam Prize for Natural Sciences, though John said this one is "special, in that it comes from my home country and it's a real shot in the arm in terms of carrying out future research."2 


  1. Chung, E. (2021, November 17). University of Toronto professor Sajeev John is 2021 winner of $1M Herzberg medal. Retrieved from
  2. Natural Sciences and Engineering Research Council of Canada. (2021, November 17). Sajeev John. Retrieved from
  3. Natural Sciences and Engineering Research Council of Canada. (2020). Gerhard Herzberg Canada Gold Medal for Science and Engineering. Retrieved from