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Title: Sub-Hertz resonance by weak measurement
Weak measurement (WM) with state pre- and post-selection can amplify otherwise undetectable small signals and thus has potential in precision measurement applications. Although frequency measurements offer the hitherto highest precision due to the stable narrow atomic transitions, it remains a long-standing interest to develop new schemes to further escalate their performance. Here, we demonstrate a WM-enhanced correlation spectroscopy technique capable of narrowing the resonance linewidth down to 0.1 Hz in a room-temperature atomic vapour cell. The potential of this technique for precision measurement is demonstrated through weak magnetic-field sensing. By judiciously pre- and post-selecting frequency-modulated input and output optical states in a nearly orthogonal manner, a sensitivity of 7 fT Hz^(−1/2) at a low frequency near DC is achieved using only one laser beam with 15 µW of power. Additionally, our results extend the WM framework to a non-Hermitian Hamiltonian and shed new light on metrology and bio-magnetic field sensing.  more » « less
Award ID(s):
1806519 1741693
PAR ID:
10157674
Author(s) / Creator(s):
; ; ; ; ;
Date Published:
Journal Name:
Nature communications
Volume:
11
ISSN:
2041-1723
Page Range / eLocation ID:
1752
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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