Scientists at Northwestern and Columbia universities have developed a tiny new kind of bio-compatible laser that could, theoretically, be implanted inside living tissues without causing them damage. Measuring less than 150 nanometers in thickness and requiring minimal amounts of power, the researchers are hopeful that further down the track the microscopic device could come to open up new treatments for neurological disorders and diagnosis of diseases.
So why would we want to place a laser inside of us, of all places? Scientists have long been investigating ways of leveraging light to improve patient outcomes for different conditions. These include using various forms of laser therapy to attack cancer cells, remove diseased tissue from delicate areas and to blast away toxic brain proteins that can give rise to Alzheimer’s and Parkinson's.
Similarly, lasers also hold great potential as a tool for detecting cancers and other diseases. Earlier this year, for example, scientists at the University of Arkansas published a paper describing a tool that uses a laser to heat up tumor cells circulating around the bloodstream in a way that makes them detectable via ultrasound. The same laser can then be applied, from outside the body, to heat the cells further and kill them.
But placing these kinds of devices in the thick of the action could open up some exciting possibilities. The newly developed device is made predominantly from glass and measures between 50 and 150 nanometers thick, making it around one thousand times thinner than a human hair. Progress has been made in developing lasers at this scale before, but they generally call on ultraviolet light to power them, which isn’t always ideal.
“This is bad because the unconventional environments in which people want to use small lasers are highly susceptible to damage from UV light and the excess heat generated by inefficient operation,” says P. James Schuck, an associate professor of mechanical engineering at Columbia.
Schuck and his team instead turned to a process known as photon upconversion, where low-energy photons are absorbed and channeled into a single photon with a higher energy output. In doing so, the researchers turned low-energy biocompatible infrared photons into visible laser beams.
“Our nanolaser is transparent but can generate visible photons when optically pumped with light our eyes cannot see,” says Teri Odom, the Charles E. and Emma H. Morrison Professor of Chemistry in Northwestern’s Weinberg College of Arts and Sciences. “The continuous wave, low-power characteristics will open numerous new applications, especially in biological imaging.”
In addition to inside the body, the researchers say the nanolaser could also find applications in other confined spaces, such as quantum circuits and microprocessors.
The team’s research was published in the journal Nature Materials.
Source: Northwestern University
