YSM Issue 94.2

Electrical Engineering
FOCUS
GENERATING
RANDOMNESS
A Laser-Based Scramble
for Random Numbers
Introducing a new mechanism, a hundred times faster than before
BY ALEXA JEANNE LOSTE
ART BY ELAINE CHENG
When you play the violin, you can trace back its sound to the vibration of its
strings. These energy vibrations—the sound waves—transfer from the strings
to the violin’s bridge, and then to its body, eventually vibrating the air before
reaching our ears as sound. The hollow wooden body serves as a resonator for acoustic
waves. Its shape is tailored to resonate with many acoustic frequencies, producing the rich,
resonant quality of sound that we appreciate as music.
This is how Hui Cao, John C. Malone Professor of Applied Physics and of Physics at
Yale, explained the design of a new laser developed in her lab. Her team is leveraging this
innovative technology to generate random numbers at revolutionary speeds.
In an article published in Science on February 26, Cao and her collaborators wrote about
their new laser design with a random bit generation (RBG) rate of two hundred fifty terabits
per second—faster than existing versions by more than a hundredfold. Functioning by
a completely different mechanism, their laser uses many different channels to generate
random numbers in parallel, while increasing the RBG rate of each individual channel.
www.yalescientific.org
May 2021 Yale Scientific Magazine 19