Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

U of T Study Looks Inside ’beating Heart’ Of Lasers

28.05.2003


A new study by University of Toronto researchers offers the first-ever glimpse inside a laser while it’s operating, a breakthrough that could lead to more powerful and efficient lasers for fibre-optic communication systems.



“We’ve seen the inner workings of a laser in action,” says investigator Ted Sargent, a professor in the Edward S. Rogers Sr. Department of Electrical and Computer Engineering. “We’ve produced a topographical map of the landscape that electrons see as they flow into these lasers to produce light.” He says the findings could influence laser design, change the diagnosis of faulty lasers and potentially reduce manufacturing costs. The study, which will appear in the June 9 issue of the journal Applied Physics Letters, offers direct experimental insight into how lasers function, says Sargent, who holds the Nortel Networks-Canada Research Chair in Emerging Technologies.

Lasers are created by growing a complex and carefully designed series of nanometer-sized layers of crystals on a disk of semiconductor material known as a wafer, Sargent explains. Ridges are etched into the crystal surface to guide laser light, thin metal layers are added on top and bottom and the wafer is then cut into tiny cubes or chips. During the laser’s operation, an electrical current flows into the chip, providing the energy to generate intense light at a specific wavelength used in fibre-optic communications.


In their study, researchers focused on the “beating heart” portion of the laser (called the active region), where electronic energy is converted into light. Using a technique called scanning voltage microscopy, they examined the surface of an operating laser, picking up differences in voltage. These differences translate to a topographical image of the laser’s energy surface, allowing researchers to visualize the forces an electron experiences along its path into the active region, Sargent says.

The team used its newly acquired information about the inside operations of the laser to determine the fraction of electric current that contributed to producing light. The balance of electrons are undesirably diverted from the active region: such current leakage wastes electrons and heats the device up, degrading performance.

“We used direct imaging to resolve a contentious issue in the field: the effectiveness of electronic funnelling into the active region of a ridge-waveguide laser,” says Dayan Ban, the U of T doctoral candidate who made the measurements. “Previously, uncorroborated models had fueled speculation by yielding divergent results. Now we know where the electrons go.” Ban is now a researcher at the Institute for Microstructural Sciences of the National Research Council of Canada.

“Direct imaging of the functions that drive the action of a living laser could transform how we think about laser ‘diagnosis and therapy,’” says Sargent, referring to the measurement and optimization of laser structures and their determination of the devices’ inner workings. Currently, designers use a variety of computer simulations to model how lasers work, but the U of T research may determine which simulations are the most accurate design tools. “With accurate models,” says Sargent, “the designs we can create are more likely to result in devices that meet design requirements.”

Co-investigator St. John Dixon-Warren, a physical chemist from Bookham Technology, a U.K.-based optical components manufacturer located in Kanata, Ont., says their research could also help in diagnosing faulty lasers. “If a particular laser fails,” says Dixon-Warren, “the kind of measurements that we are taking could provide some idea of why it failed and the design could then be modified.”

Sargent says the findings could have larger implications for the creation of optical circuits for fibre-optic communication. “If we could fully develop these models and fully understand how lasers work, then we could start to build optical circuits with confidence and high probability of success,” he says. “Optical chips akin to electronic integrated circuits in computers must be founded on a deep and broad understanding of the processes at work inside current and future generations of lasers.”

The research was supported by Nortel Networks Optical Components (recently acquired by Bookham Technology), the Natural Sciences and Engineering Research Council of Canada, the Ontario Research and Development Challenge Fund, the Canada Foundation for Innovation, the Ontario Innovation Trust and the Canada Research Chairs Program.

CONTACT:
Ted Sargent
Edward S. Rogers Sr. Department of Electrical and Computer Engineering
416-946-5051
ted.sargent@utoronto.ca

Nicolle Wahl | University of Toronto
Further information:
http://www.utoronto.ca

More articles from Physics and Astronomy:

nachricht First Juno science results supported by University of Leicester's Jupiter 'forecast'
26.05.2017 | University of Leicester

nachricht Measured for the first time: Direction of light waves changed by quantum effect
24.05.2017 | Vienna University of Technology

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Can the immune system be boosted against Staphylococcus aureus by delivery of messenger RNA?

Staphylococcus aureus is a feared pathogen (MRSA, multi-resistant S. aureus) due to frequent resistances against many antibiotics, especially in hospital infections. Researchers at the Paul-Ehrlich-Institut have identified immunological processes that prevent a successful immune response directed against the pathogenic agent. The delivery of bacterial proteins with RNA adjuvant or messenger RNA (mRNA) into immune cells allows the re-direction of the immune response towards an active defense against S. aureus. This could be of significant importance for the development of an effective vaccine. PLOS Pathogens has published these research results online on 25 May 2017.

Staphylococcus aureus (S. aureus) is a bacterium that colonizes by far more than half of the skin and the mucosa of adults, usually without causing infections....

Im Focus: A quantum walk of photons

Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.

The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....

Im Focus: Turmoil in sluggish electrons’ existence

An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.

We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

Im Focus: World's thinnest hologram paves path to new 3-D world

Nano-hologram paves way for integration of 3-D holography into everyday electronics

An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

AWK Aachen Machine Tool Colloquium 2017: Internet of Production for Agile Enterprises

23.05.2017 | Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

 
Latest News

How herpesviruses win the footrace against the immune system

26.05.2017 | Life Sciences

Water forms 'spine of hydration' around DNA, group finds

26.05.2017 | Life Sciences

First Juno science results supported by University of Leicester's Jupiter 'forecast'

26.05.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>