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INTEGRATED AND MINIATURIZED ATOMIC SENSORS
Selected Publications
"Cavity-enhanced detection of spin polarization in a microfabricated atomic vapor cell"
Phys. Rev. Applied 21, 064014
"Laser-written micro-channel atomic magnetometer"
arxiv.org/abs/2404.14345
"Laser-written vapor cells for chip-scale atomic sensing and spectroscopy"
Opt. Express 30, 27149-27163 (2022)
"Miniature biplanar coils for alkali-metal-vapor magnetometry"
Phys. Rev. Applied 18, 014036 (2022)
Selected Publications
"Cavity-enhanced detection of spin polarization in a microfabricated atomic vapor cell"
Phys. Rev. Applied 21, 064014
"Laser-written micro-channel atomic magnetometer"
arxiv.org/abs/2404.14345
"Laser-written vapor cells for chip-scale atomic sensing and spectroscopy"
Opt. Express 30, 27149-27163 (2022)
"Miniature biplanar coils for alkali-metal-vapor magnetometry"
Phys. Rev. Applied 18, 014036 (2022)
![Picture](/uploads/1/1/8/5/118533451/published/romalismeg.png?1661784397)
OPTICAL MAGNETOMETRY
Selected Publications
"Femtotesla nearly-quantum-noise-limited pulsed gradiometer at Earth-scale fields"
Phys. Rev. Applied 18, L021001 (2022)
"Femtotesla Direct Magnetic Gradiometer Using a Single Multipass Cell"
Phys. Rev. Applied 15, 014004 (2021)
"Portable Magnetometry for Detection of Biomagnetism in Ambient Environments" Phys. Rev. Applied 14 , 011002 (2020)
"Shot-noise-limited magnetometer with sub-picotesla sensitivity at room temperature" Rev. Sci. Inst. 85 (11), 113108 (2014)
Selected Publications
"Femtotesla nearly-quantum-noise-limited pulsed gradiometer at Earth-scale fields"
Phys. Rev. Applied 18, L021001 (2022)
"Femtotesla Direct Magnetic Gradiometer Using a Single Multipass Cell"
Phys. Rev. Applied 15, 014004 (2021)
"Portable Magnetometry for Detection of Biomagnetism in Ambient Environments" Phys. Rev. Applied 14 , 011002 (2020)
"Shot-noise-limited magnetometer with sub-picotesla sensitivity at room temperature" Rev. Sci. Inst. 85 (11), 113108 (2014)
![Picture](/uploads/1/1/8/5/118533451/editor/squeezedsns.png?1595453198)
QUANTUM-ENHANCED ATOMIC SENSORS
Selected Publications
"Quantum-enhanced magnetometry at optimal number density"
C. Troullinou, V. G. Lucivero, and M. W. Mitchell, Phys. Rev. Lett. 131 (13), 133602 (2023)
"Squeezed-light enhancement and backaction evasion in a high-sensitivity optically pumped magnetometer" Phys. Rev. Lett. 127 (19), 193601 (2021)
"Squeezed-light spin noise spectroscopy" Phys. Rev. A 93 (5), 053802 (2016)
"Sensitivity, quantum limits, and quantum enhancement of noise spectroscopies"
Phys. Rev. A 95 (041803(R)) (2016)
"Signal tracking beyond the time resolution of an atomic sensor by Kalman filtering"
Phys. Rev. Lett. 120 (4), 040503 (2018)
Selected Publications
"Quantum-enhanced magnetometry at optimal number density"
C. Troullinou, V. G. Lucivero, and M. W. Mitchell, Phys. Rev. Lett. 131 (13), 133602 (2023)
"Squeezed-light enhancement and backaction evasion in a high-sensitivity optically pumped magnetometer" Phys. Rev. Lett. 127 (19), 193601 (2021)
"Squeezed-light spin noise spectroscopy" Phys. Rev. A 93 (5), 053802 (2016)
"Sensitivity, quantum limits, and quantum enhancement of noise spectroscopies"
Phys. Rev. A 95 (041803(R)) (2016)
"Signal tracking beyond the time resolution of an atomic sensor by Kalman filtering"
Phys. Rev. Lett. 120 (4), 040503 (2018)
![Picture](/uploads/1/1/8/5/118533451/editor/quantumentanglement.jpg?1595453710)
QUANTUM ENTANGLEMENT AND NOISE
Selected Publications
"Measurement-induced, spatially-extended entanglement in a hot, strongly-interacting atomic system" Nature communications 11 (1), 1-9 (2020)
"Correlation function of spin noise due to atomic diffusion"
Physical Review A 96 (6), 062702 (2017)
"Effects of spin-exchange collisions on the fluctuation spectra of hot alkali vapors" K. Mouloudakis, G. Vasilakis, V. G. Lucivero, J. Kong, I. K. Kominis,
M. W. Mitchell, Phys. Rev. A 106(2), 023113 (2022)
"Macroscopic quantum state analyzed particle by particle"
Physical Review Letters 114 (12), 120402 (2015)
Selected Publications
"Measurement-induced, spatially-extended entanglement in a hot, strongly-interacting atomic system" Nature communications 11 (1), 1-9 (2020)
"Correlation function of spin noise due to atomic diffusion"
Physical Review A 96 (6), 062702 (2017)
"Effects of spin-exchange collisions on the fluctuation spectra of hot alkali vapors" K. Mouloudakis, G. Vasilakis, V. G. Lucivero, J. Kong, I. K. Kominis,
M. W. Mitchell, Phys. Rev. A 106(2), 023113 (2022)
"Macroscopic quantum state analyzed particle by particle"
Physical Review Letters 114 (12), 120402 (2015)
(2016-2019) Postdoctoral Research Associate at Princeton Univeristy (link to Romalis group)
Since 2016 to 2019 I worked as Postdoctoral Research Associate within the atomic physics group led by Prof. Michael Romalis at the Physics Department of Princeton University in New Jersey. The group is world leading in the field of optical magnetometry, in which laser light and high-density alkali-metal vapors are used to measure either scalar or RF magnetic fields, reaching ultra-high sensitivity below the femtoTesla (sub-fT) level. Such atomic sensors are fundamentally limited by the laws of quantum mechanics and techniques based on quantum properties like optical squeezing, spin squeezing and atomic entanglement have allowed physicists to improve their sensitivity beyond what is obtainable by using classical resources. Such magnetometers are particularly suitable for practical applications in biomagnetism and medicine as well as in space science and tests of fundamental physics. Furthermore they are already being built into commercial and chip-scale magnetic sensors. I am currently working on a new generation of multipass vapor cells in order to perform high-sensitive magnetometers, atomic physics and quantum optics experiments.
(2011-2016) PhD Thesis @ICFO
Link: "Quantum metrology with high-density atomic vapors and squeezed states of light"
Link: "Quantum metrology with high-density atomic vapors and squeezed states of light"
![Picture](/uploads/1/1/8/5/118533451/published/coverpicfinalpng.png?1521340545)
Nowadays there is a considerable progress in optical magnetometry and spin noise spectroscopy, which use magnetically-sensitive atomic ensembles and optical readout, approaching the limits set by quantum mechanics. In recent years optical magnetometers have become the most sensitive instruments for measuring low frequency magnetic fields, achieving sub-femtotesla sensitivity and surpassing the competitive superconducting quantum interference devices (SQUIDs), and have found applications in biomedicine, geophysics, space science as well as in tests of fundamental physics.
Another emerging technique is spin noise spectroscopy (SNS), which allows one to determine physical properties of an unperturbed spin system from its power noise spectrum. In the last decade technological advances like real-time spectrum analyzers and shot-noise-limited detectors have allowed improvements in the sensitivity of spin noise detection leading to a broad range of applications in both atomic and solid state physics.
The main goal of this thesis is to address a major outstanding question: whether squeezed light can improve the sensitivity of atomic sensors under optimal sensitivity conditions, typically in a high-density regime due to the statistical advantage of using more atoms.
Firstly, we describe the design, construction and characterization of a new versatile experimental apparatus for the study of squeezed-light atomic spectroscopy within a high-density regime and low-noise magnetic environment. The new experimental system is combined with an existing source of polarization squeezed light based on spontaneous parametric down conversion (SPDC) in a nonlinear crystal, which is the active medium of an optical parametric oscillator.
Secondly, we report the first experimental demonstration of quantum-enhanced spin noise spectroscopy of natural abundance Rb via polarization squeezing of the probe beam. We found that input squeezing of 3:0 dB improves the signal-to-noise ratio by 1.5 dB to 2.6 dB, covering the ranges used in optimized spin noise spectroscopy experiments. We also show that squeezing improves the trade-o between statistical sensitivity and broadening eects.
Next, we introduce a novel theoretical model by defining a standard quantum limit (SQL) for optically-detected noise spectroscopy, identified as a bound to the covariance of the parameters estimated by fitting power noise spectra. We test the model for spin noise spectroscopy of natural abundance Rb and we demonstrate experimental performance of SNS at the SQL for a coherent probe and below the SQL for a polarization squeezed probe.
Finally, we report an optical magnetometer based on amplitude modulated optical rotation (AMOR), using a 85Rb vapor cell, that achieves room temperature sensitivity of 70 fT and we demonstrate its photon shot-noisel-imited (SNL) behaviour over a broad dynamic range. While no quantum resources of light were used in this second experiment, the combination of best sensitivity, in the class of room-temperature scalar magnetometers, and SNL operation makes the system a promising candidate for application of squeezed light to an optimized optical magnetometer with best-in-class sensitivity.
Another emerging technique is spin noise spectroscopy (SNS), which allows one to determine physical properties of an unperturbed spin system from its power noise spectrum. In the last decade technological advances like real-time spectrum analyzers and shot-noise-limited detectors have allowed improvements in the sensitivity of spin noise detection leading to a broad range of applications in both atomic and solid state physics.
The main goal of this thesis is to address a major outstanding question: whether squeezed light can improve the sensitivity of atomic sensors under optimal sensitivity conditions, typically in a high-density regime due to the statistical advantage of using more atoms.
Firstly, we describe the design, construction and characterization of a new versatile experimental apparatus for the study of squeezed-light atomic spectroscopy within a high-density regime and low-noise magnetic environment. The new experimental system is combined with an existing source of polarization squeezed light based on spontaneous parametric down conversion (SPDC) in a nonlinear crystal, which is the active medium of an optical parametric oscillator.
Secondly, we report the first experimental demonstration of quantum-enhanced spin noise spectroscopy of natural abundance Rb via polarization squeezing of the probe beam. We found that input squeezing of 3:0 dB improves the signal-to-noise ratio by 1.5 dB to 2.6 dB, covering the ranges used in optimized spin noise spectroscopy experiments. We also show that squeezing improves the trade-o between statistical sensitivity and broadening eects.
Next, we introduce a novel theoretical model by defining a standard quantum limit (SQL) for optically-detected noise spectroscopy, identified as a bound to the covariance of the parameters estimated by fitting power noise spectra. We test the model for spin noise spectroscopy of natural abundance Rb and we demonstrate experimental performance of SNS at the SQL for a coherent probe and below the SQL for a polarization squeezed probe.
Finally, we report an optical magnetometer based on amplitude modulated optical rotation (AMOR), using a 85Rb vapor cell, that achieves room temperature sensitivity of 70 fT and we demonstrate its photon shot-noisel-imited (SNL) behaviour over a broad dynamic range. While no quantum resources of light were used in this second experiment, the combination of best sensitivity, in the class of room-temperature scalar magnetometers, and SNL operation makes the system a promising candidate for application of squeezed light to an optimized optical magnetometer with best-in-class sensitivity.