optical device tagged posts

Engineers at the University of California San Diego have developed an optical device that reveals hidden images and changes colors in response to different levels of humidity. The technology, published in Light: Science & Applications, could lead to the development of new anti-counterfeiting labels, secure data storage, interactive displays, and environmental sensors.

The device works by displaying different images depending on moisture levels in the air...

Kerry Vahala and collaborators from UC Santa Barbara have found a unique solution to an optics problem. When we last checked in with Caltech’s Kerry Vahala three years ago, his lab had recently reported the development of a new optical device called a turnkey frequency microcomb that has applications in digital communications, precision time keeping, spectroscopy, and even astronomy.

This device, fabricated on a silicon wafer, takes input laser light of one frequency and converts it into an evenly spaced set of many distinct frequencies that form a train of pulses whose length can be as short as 100 femtoseconds (quadrillionths of a second). (The comb in the name comes from the frequencies being spaced like the teeth of a hair comb.)

Now Vahala (BS ’80, MS ’81,...