Researchers describe a laser interrogation system built around a commercial frequency-quadrupled diode laser that reaches roughly 500 mW at 296.8 nm, used to probe a thorium-229-doped crystal sample. The setup combines offset-frequency phase locking and Pound-Drever-Hall stabilization to a reference cavity, with a photomultiplier tube detecting fluorescence signals inside a vacuum chamber, and the clock laser's frequency also compared against an optical frequency comb.
nature.com
· 2026-10-07
A research team built an integrated frequency-comb device that inverts the usual design: instead of cascading outward from a single pump laser, two lasers spaced exactly one octave apart drive a soliton inside a chip-based resonator, generating a comb that fills the gap between them. The resulting octave-spanning comb, spanning telecom to visible wavelengths, automatically aligns to both pump lasers across multiple fabricated chips and setups, giving it a well-defined zero-frequency offset that is easy to detect and stabilize. The team used this single device to perform optical frequency synthesis, low-noise millimetre-wave generation, and optical clock readout by simply changing which signals the pumps were locked to.
nature.com
· 2026-09-30
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