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Lock-in amplifier

About: Lock-in amplifier is a(n) research topic. Over the lifetime, 521 publication(s) have been published within this topic receiving 4455 citation(s).
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Journal ArticleDOI
Abstract: The basic principles behind the operation of a lock‐in amplifier are described. Particular emphasis is placed on looking at the frequency components of the signal present at the various stages of the lock‐in during a typical measurement. The description presented here has been used successfully to explain lock‐in operation to upper‐level laboratory students at Oberlin College.

215 citations


Journal ArticleDOI
05 May 2011-Nature
Abstract: Quantum metrology uses tools from quantum information science to improve measurement signal-to-noise ratios. The challenge is to increase sensitivity while reducing susceptibility to noise, tasks that are often in conflict. Lock-in measurement is a detection scheme designed to overcome this difficulty by spectrally separating signal from noise. Here we report on the implementation of a quantum analogue to the classical lock-in amplifier. All the lock-in operations--modulation, detection and mixing--are performed through the application of non-commuting quantum operators to the electronic spin state of a single, trapped Sr(+) ion. We significantly increase its sensitivity to external fields while extending phase coherence by three orders of magnitude, to more than one second. Using this technique, we measure frequency shifts with a sensitivity of 0.42 Hz Hz(-1/2) (corresponding to a magnetic field measurement sensitivity of 15 pT Hz(-1/2)), obtaining an uncertainty of less than 10 mHz (350 fT) after 3,720 seconds of averaging. These sensitivities are limited by quantum projection noise and improve on other single-spin probe technologies by two orders of magnitude. Our reported sensitivity is sufficient for the measurement of parity non-conservation, as well as the detection of the magnetic field of a single electronic spin one micrometre from an ion detector with nanometre resolution. As a first application, we perform light shift spectroscopy of a narrow optical quadrupole transition. Finally, we emphasize that the quantum lock-in technique is generic and can potentially enhance the sensitivity of any quantum sensor.

133 citations


01 May 2011-
TL;DR: The implementation of a quantum analogue to the classical lock-in amplifier is reported on, which significantly increases its sensitivity to external fields while extending phase coherence by three orders of magnitude and can potentially enhance the sensitivity of any quantum sensor.
Abstract: Quantum metrology uses tools from quantum information science to improve measurement signal-to-noise ratios. The challenge is to increase sensitivity while reducing susceptibility to noise, tasks that are often in conflict. Lock-in measurement is a detection scheme designed to overcome this difficulty by spectrally separating signal from noise. Here we report on the implementation of a quantum analogue to the classical lock-in amplifier. All the lock-in operations--modulation, detection and mixing--are performed through the application of non-commuting quantum operators to the electronic spin state of a single, trapped Sr(+) ion. We significantly increase its sensitivity to external fields while extending phase coherence by three orders of magnitude, to more than one second. Using this technique, we measure frequency shifts with a sensitivity of 0.42 Hz Hz(-1/2) (corresponding to a magnetic field measurement sensitivity of 15 pT Hz(-1/2)), obtaining an uncertainty of less than 10 mHz (350 fT) after 3,720 seconds of averaging. These sensitivities are limited by quantum projection noise and improve on other single-spin probe technologies by two orders of magnitude. Our reported sensitivity is sufficient for the measurement of parity non-conservation, as well as the detection of the magnetic field of a single electronic spin one micrometre from an ion detector with nanometre resolution. As a first application, we perform light shift spectroscopy of a narrow optical quadrupole transition. Finally, we emphasize that the quantum lock-in technique is generic and can potentially enhance the sensitivity of any quantum sensor.

108 citations


Journal ArticleDOI
TL;DR: A novel digital lock-in detection technique for simultaneously measuring the amplitude and phase of multiple amplitude-modulated signals and can be performed as a simple matrix multiplication, which considerably reduces the computation time.
Abstract: We introduce a novel digital lock-in detection technique for simultaneously measuring the amplitude and phase of multiple amplitude-modulated signals. Using particular modulation and sampling constraints and averaging filters, we achieve optimal noise reduction and discrimination between sources of different modulation frequencies. Furthermore, it is shown that the digital lock-in technique can be performed as a simple matrix multiplication, which considerably reduces the computation time. The digital lock-in algorithm is described and analyzed under certain sampling and modulation conditions, and results are shown for both numerical and experimental data.

99 citations


Journal ArticleDOI
Abstract: A novel optical information processing system by synthesis of the coherence function is built up to extract a two dimensional image from a three-dimensional object at a tenable depth with neither mechanical scanning nor digital calculation. In this system, a two-dimensional optical lock-in amplifier with the microchannel spatial light modulator is developed to detect selectively the coherence component, so that the limitation to the depth resolution introduced by the holographic detection which was used in our previous systems is overcome. Selective image extraction Is demonstrated successfully.

99 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202118
202021
201924
201824
201734
201634

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Topic's top 5 most impactful authors

Giuseppe Ferri

8 papers, 245 citations

Andrea De Marcellis

7 papers, 36 citations

Belén Calvo

7 papers, 61 citations

Yasuhiro Tanaka

6 papers, 19 citations

Atsuhiro Nishikata

5 papers, 20 citations