Celebrate Princeton Invention: Craig Arnold

Craig Arnold

Able to adjust its focus more than 100,000 times faster than the human eye, the TAG Lens invented by mechanical and aerospace engineering professor Craig Arnold and his colleagues has applications in materials processing and imaging. (Photo: Brian Wilson)

Name: Craig Arnold, associate professor of mechanical and aerospace engineering

Invention: Tunable Acoustic Gradient Index of Refraction Lens (TAG Lens)

What it does: The TAG lens features a cylinder made of a special material that vibrates when electricity is passed through it, enclosed inside a fluid-filled chamber. Controlling the flow of electricity changes the vibrations that propagate through the fluid, changing the lens' focus more than 100,000 times faster than the human eye can refocus.

Inspiration:
After developing a low-cost lens to shape laser beam output into different patterns, Arnold and his colleagues focused their attention on understanding how the device worked and its potential applications. Finding that the lens had the unique ability to focus rapidly at a wide range of focal lengths, they realized its potential went far beyond the original intended purpose, with numerous applications in materials processing and imaging.

Collaborators: Euan McLeod, a 2009 Ph.D. recipient, and Alexander Mermillod-Blondin, a former postdoctoral researcher in the Arnold lab

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