Univ of Illinois Micro + Nanotechnology Lab 2016 Highlights Report | Page 8

Advancing transistor laser technology
Tumor shape affects how cancer cells spread
Graduate students Junyi Qiu and Curtis Wang and Professor Milton Feng found that light stimulates switching speed in the transistor laser , a device Feng co-invented with Professor Nick Holonyak Jr . in 2004 .

Advancing transistor laser technology

Today , data centers process terabytes of data per second for billions of mobile phones and computers worldwide . However , the diode laser , which is key to high-speed data transmission , is reaching the upper end of its switching speed . Invented by ECE Professors Milton Feng and Nick Holonyak Jr ., the transistor laser is a next-generation alternative technology capable of operating 100 times faster than a conventional laser . In their latest work , Feng , Holonyak , and students found that not only does photon-assisted tunneling occur in the transistor laser , but that it in turn stimulates the photon absorption process within the laser cavity , making the optical switching in the device even faster and allowing for ultra-high-speed signal modulation . The team can directly modulate the laser into the femtosecond range . As they continue to explore the transistor laser ’ s unique physics , the researchers are forming industry partnerships to commercialize the technology for energyefficient big data transfer .
Sources : Journal of Applied Physics , “ Intra-cavity photon-assisted tunneling collector-base voltage-mediated electron-hole spontaneous-stimulated recombination transistor laser ,” volume 119 , issue 8 , February 2016 . Journal of Applied Physics , “ Tunneling modulation of a quantum-well transistor laser ,” volume 120 , issue 20 , November 2016 .

Tumor shape affects how cancer cells spread

Materials Science & Engineering faculty member Kris Kilian and a team of researchers discovered that the curve along the edge of a tumor may play a large role in activating a few cancer cells to break away and spread to other parts of the body . Using engineered tissue environments in various shapes and patterns , Kilian ’ s study of skin cancer found that the more curved the cell cultures were , the more cancer cells at the edges displayed markers of stem cell characteristics — the key to spreading to other tissues . Kilian ’ s group specializes in tissue engineering to create models of tumors in order to more accurately study cancer processes in a culture dish . In the new study , the researchers found that cancer stem cells seemed to appear in the highest numbers along the edges of the engineered tumor environments , particularly where there were corners and convex curves .
Source : Nature Materials , “ Interfacial geometry dictates cancer cell tumorigenicity ,” volume 15 , page 856 , April 4 , 2016 .
Illinois researchers found that the shape of a tumor may play a role in how cancer cells become primed to spread . From left : MatSci Assistant Professor Kristopher Kilian , graduate student Junmin Lee , and Veterinary Medicine Professor Timothy Fan .
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