Matthew A. Norcia

Reduced spin measurement back-action for a phase sensitivity ten times beyond the standard quantum limit

The phase of a collection of spins is measured with a sensitivity ten times beyond the limit set by the quantum noise of an unentangled ensemble of 87Rb atoms. A cavity-enhanced probe of an optical cycling transition is employed to mitigate back-action associated with state-changing transitions induced by the probe.

Superradiance on the millihertz linewidth strontium clock transition

Researchers demonstrate superradiant emission from the 150-s lifetime strontium clock transition. Laser frequency noise contributes a significant limitation to today’s best atomic clocks. A proposed solution to this problem is to create a superradiant laser using an optical clock transition as its gain medium. This laser would act as an active atomic clock and would be highly immune to the fluctuations in reference cavity length that limit today’s best lasers. We demonstrate and characterize superradiant emission from the millihertz linewidth clock transition in an ensemble of laser-cooled 87Sr atoms trapped within a high-finesse optical cavity. We measure a collective enhancement of the emission rate into the cavity mode by a factor of more than 10,000 compared to independently radiating atoms. We also demonstrate a method for seeding superradiant emission and observe interference between two independent transitions lasing simultaneously. We use this interference to characterize the relative spectral properties of the two lasing subensembles.

Cold-Strontium Laser in the Superradiant Crossover Regime

Recent proposals suggest that lasers based on narrow dipole-forbidden transitions in cold alkaline earth atoms could achieve linewidths that are orders of magnitude smaller than linewidths of any existing lasers. Here, we demonstrate a laser based on the 7.5 kHz linewidth dipole forbidden

Strong coupling on a forbidden transition in strontium and nondestructive atom counting

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Role of atoms in atomic gravitational-wave detectors

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Narrow-line laser cooling by adiabatic transfer

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Cavity-mediated collective spin-exchange interactions in a strontium superradiant laser

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Reducing collective quantum state rotation errors with reversible dephasing

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Simple Laser Stabilization to the Strontium 88Sr Transition at 707 nm

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Magnetically Induced Optical Transparency on a Forbidden Transition in Strontium for Cavity-Enhanced Spectroscopy

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