Optical Frequency Comb
A laser whose spectrum is millions of perfectly spaced lines, a ruler for light. The Nobel-winning Boulder invention that lets optical atomic clocks be read out.
An optical frequency comb is a laser whose spectrum is millions of perfectly spaced spectral lines, a ruler for light. It solved a problem that had stumped metrology for decades: optical waves oscillate hundreds of trillions of times per second, far too fast for any electronics to count. The comb bridges optical and microwave frequencies, letting atomic clocks based on optical transitions actually be read out.
This is bedrock Boulder history: John Hall at JILA shared the 2005 Nobel Prize for the comb's development, and the technology has been leaking out of Boulder labs into companies ever since. Vescent and Octave Photonics both build comb hardware, and combs now appear in compact clocks, LIDAR, spectroscopy, and the control systems of atomic quantum computers. If the Quantum Valley has a founding artifact, it's arguably the comb.