When you think of a particle accelerator, you usually think of some giant cyclotron with heavy-duty equipment in a massive mad-science lab. But scientists now believe they can create particle accelerators that can fit on a chip smaller than a penny. The device uses lasers and dielectrics instead of electric fields and metal. The conventional accelerators are limited by the peak fields the metallic surfaces can withstand. Dielectric materials can withstand much higher fields but, of course, don’t conduct electricity.
Physicists fabricated a 225 nanometers wide channel in various sizes up to 0.5 millimeters long. An electron beam moves through the channel. Very short infrared laser pulses on top of the channels accelerate the electrons down it using tiny silicon pillars.
The electron beam entered the channel at 28,400 electron volts. They exited at 40,700 electron volts, a substantial increase. The tiny pillars are only two microns high, so fabrication is tricky. Possible applications include cancer treatment, electron microscopy, and the creation of compact high-energy lasers.
The nanofabrication required for these devices won’t be in our garage any time soon. However, we hope this might lead to a new class of devices that we can use to build exciting new things. After all, remember how it used to be hard to build things using a laser?