Theoretical physicist Sajeev John has received Canada’s highest science and engineering honour, the prestigious Gerhard Herzberg Canada Gold Medal.
John is receiving the award for his groundbreaking research and fundamental advancements in confining and harnessing the flow of photons of light in a manner analogous to harnessing the flow of electrons.
The medal also recognizes John for his leadership in efforts to transform this research into groundbreaking applications in optical micro-chips, optical communications and information processing, laser technologies, solar-energy harvesting and clinical medicine – including life-saving surgical tools and techniques.
“I am profoundly honoured and feel singularly energized to bring to broader fruition the work I began on light-trapping crystals,” says John, a University Professor in the Faculty of Arts & Science’s department of physics.
“The Herzberg Gold Medal offers a unique opportunity for creativity and unfettered pursuit of essential applications such as the world’s most efficient, lightweight silicon solar cells; light-trapping to enhance artificial photosynthesis for solar fuel production; development of the most compact lab-in-a-photonic-crystal sensors for early-stage disease detection and diagnosis; and much more.”
Named after the Canadian physicist and Nobel laureate in chemistry, the Gerhard Herzberg Canada Gold Medal recognizes the excellence and impact of a recipient’s research. It is awarded annually by the Natural Sciences and Engineering Research Council of Canada (NSERC).
“Professor John is truly deserving of the country’s highest scientific honour,” says Melanie Woodin, dean of the Faculty of Arts & Science. “Not only has his work been foundational, it has also had an impact in physics, chemistry, engineering and medicine, and is leading to advancements that are benefiting people’s lives.”
John’s research provides a solution to the problem that photons do not tend to flow along confined pathways like electrons but instead disperse or are absorbed.
According to Kim Strong, chair of the department of physics, “Professor John’s research laid out the theoretical foundation for special materials – called Photonic Band Gap (PBG) materials – that allow confinement, or localization, of photons to a microscopic region with the size of the wavelength of light.”
“Once you know how to confine photons to a single location,” she says, “you can confine their motion along prescribed microscopic circuit paths, analogous to the way the motion of electrons is controlled on the nanometer scale in semiconductors.”
Following up on his theoretical work, John and his collaborators built the first large-scale silicon PBG material out of a synthetic opal and have created PBG materials that are even easier and cheaper to manufacture.
The groundbreaking work has sparked the development of novel micro-structured materials known as photonic crystals, now referred to as “semiconductors of light.” Ultimately, the breakthrough will enable computer chips to operate with photons instead of electrons.
Among many impacts beyond the lab, research into PBG materials has already produced life-saving advancements in clinical medicine. In 2004, laser surgery was performed on a patient to remove a previously treated tumour that was recurring and remained life-threatening. A final, successful surgery was carried out using a hollow-core photonic band gap fibre. Thousands of similar procedures have been performed using PBG fibres and several major medical centres are now testing PBG-fibre-based laser surgery tools.
“The University of Toronto congratulates Sajeev John on this important recognition,” says Professor Leah Cowen, U of T’s associate vice-president of research. “From his groundbreaking work on confining and harnessing the flow of photons to his leadership in exploring applications for his research in optical micro-chips, optical communications and information processing, laser technologies, solar energy-harvesting and clinical medicine – his impact has been remarkable.”
In 1984, John received his PhD in physics from Harvard University, where he published the original paper on light localization. He was an assistant professor at Princeton University, where he pioneered the concept of photonic band gap materials. He joined U of T in 1989.
John’s research and scientific leadership earned him the 2001 King Faisal International Prize in Science (with Nobel laureate C.N. Yang). In 2007, the Institute of Electrical and Electronics Engineers (IEEE) awarded him with the International Quantum Electronics Award for “the invention of and development of light-trapping crystals and the elucidation of their properties and applications.”
NAIROBI, Kenya (AP) — The body of Ugandan Olympic athlete Rebecca Cheptegei — who died after being set on fire by her partner in Kenya — was received Friday by family and anti-femicide crusaders, ahead of her burial a day later.
Cheptegei’s family met with dozens of activists Friday who had marched to the Moi Teaching and Referral Hospital’s morgue in the western city of Eldoret while chanting anti-femicide slogans.
She is the fourth female athlete to have been killed by her partner in Kenya in yet another case of gender-based violence in recent years.
Viola Cheptoo, the founder of Tirop Angels – an organization that was formed in honor of athlete Agnes Tirop, who was stabbed to death in 2021, said stakeholders need to ensure this is the last death of an athlete due to gender-based violence.
“We are here to say that enough is enough, we are tired of burying our sisters due to GBV,” she said.
It was a somber mood at the morgue as athletes and family members viewed Cheptegei’s body which sustained 80% of burns after she was doused with gasoline by her partner Dickson Ndiema. Ndiema sustained 30% burns on his body and later succumbed.
Ndiema and Cheptegei were said to have quarreled over a piece of land that the athlete bought in Kenya, according to a report filed by the local chief.
Cheptegei competed in the women’s marathon at the Paris Olympics less than a month before the attack. She finished in 44th place.
Cheptegei’s father, Joseph, said that the body will make a brief stop at their home in the Endebess area before proceeding to Bukwo in eastern Uganda for a night vigil and burial on Saturday.
“We are in the final part of giving my daughter the last respect,” a visibly distraught Joseph said.
He told reporters last week that Ndiema was stalking and threatening Cheptegei and the family had informed police.
Four in 10 women or an estimated 41% of dating or married Kenyan women have experienced physical or sexual violence perpetrated by their current or most recent partner, according to the Kenya Demographic and Health Survey 2022.
TEL AVIV, Israel (AP) — A rare Bronze-Era jar accidentally smashed by a 4-year-old visiting a museum was back on display Wednesday after restoration experts were able to carefully piece the artifact back together.
Last month, a family from northern Israel was visiting the museum when their youngest son tipped over the jar, which smashed into pieces.
Alex Geller, the boy’s father, said his son — the youngest of three — is exceptionally curious, and that the moment he heard the crash, “please let that not be my child” was the first thought that raced through his head.
The jar has been on display at the Hecht Museum in Haifa for 35 years. It was one of the only containers of its size and from that period still complete when it was discovered.
The Bronze Age jar is one of many artifacts exhibited out in the open, part of the Hecht Museum’s vision of letting visitors explore history without glass barriers, said Inbal Rivlin, the director of the museum, which is associated with Haifa University in northern Israel.
It was likely used to hold wine or oil, and dates back to between 2200 and 1500 B.C.
Rivlin and the museum decided to turn the moment, which captured international attention, into a teaching moment, inviting the Geller family back for a special visit and hands-on activity to illustrate the restoration process.
Rivlin added that the incident provided a welcome distraction from the ongoing war in Gaza. “Well, he’s just a kid. So I think that somehow it touches the heart of the people in Israel and around the world,“ said Rivlin.
Roee Shafir, a restoration expert at the museum, said the repairs would be fairly simple, as the pieces were from a single, complete jar. Archaeologists often face the more daunting task of sifting through piles of shards from multiple objects and trying to piece them together.
Experts used 3D technology, hi-resolution videos, and special glue to painstakingly reconstruct the large jar.
Less than two weeks after it broke, the jar went back on display at the museum. The gluing process left small hairline cracks, and a few pieces are missing, but the jar’s impressive size remains.
The only noticeable difference in the exhibit was a new sign reading “please don’t touch.”
VICTORIA – The British Columbia government is partnering with a bear welfare group to reduce the number of bears being euthanized in the province.
Nicholas Scapillati, executive director of Grizzly Bear Foundation, said Monday that it comes after months-long discussions with the province on how to protect bears, with the goal to give the animals a “better and second chance at life in the wild.”
Scapillati said what’s exciting about the project is that the government is open to working with outside experts and the public.
“So, they’ll be working through Indigenous knowledge and scientific understanding, bringing in the latest techniques and training expertise from leading experts,” he said in an interview.
B.C. government data show conservation officers destroyed 603 black bears and 23 grizzly bears in 2023, while 154 black bears were killed by officers in the first six months of this year.
Scapillati said the group will publish a report with recommendations by next spring, while an independent oversight committee will be set up to review all bear encounters with conservation officers to provide advice to the government.
Environment Minister George Heyman said in a statement that they are looking for new ways to ensure conservation officers “have the trust of the communities they serve,” and the panel will make recommendations to enhance officer training and improve policies.
Lesley Fox, with the wildlife protection group The Fur-Bearers, said they’ve been calling for such a committee for decades.
“This move demonstrates the government is listening,” said Fox. “I suspect, because of the impending election, their listening skills are potentially a little sharper than they normally are.”
Fox said the partnership came from “a place of long frustration” as provincial conservation officers kill more than 500 black bears every year on average, and the public is “no longer tolerating this kind of approach.”
“I think that the conservation officer service and the B.C. government are aware they need to change, and certainly the public has been asking for it,” said Fox.
Fox said there’s a lot of optimism about the new partnership, but, as with any government, there will likely be a lot of red tape to get through.
“I think speed is going to be important, whether or not the committee has the ability to make change and make change relatively quickly without having to study an issue to death, ” said Fox.
This report by The Canadian Press was first published Sept. 9, 2024.
