• Laser & Optoelectronics Progress
  • Vol. 60, Issue 15, 1500005 (2023)
Weiyi Wang1,2 and Zhen Chai1,2,*
Author Affiliations
  • 1School of Instrumentation and Optoelectronic Engineering, Beihang University, Beijing 100191, China
  • 2Hangzhou Innovation Institute, Beihang University, Hangzhou 310023, Zhejiang, China
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    DOI: 10.3788/LOP222049 Cite this Article Set citation alerts
    Weiyi Wang, Zhen Chai. Interaction Between Laser and Thermal-Alkali Atomic Ensemble: Progress and Prospect[J]. Laser & Optoelectronics Progress, 2023, 60(15): 1500005 Copy Citation Text show less
    Structure diagram of energy level splitting of ground state and first excited state of a Rb atom. (a) Orbital energy level (orbital spin L1=0,L2=1); (b) fine structure energy level (electron spin S=1/2); (c) hyperfine structure energy level (nuclear spin I=3/2)
    Fig. 1. Structure diagram of energy level splitting of ground state and first excited state of a Rb atom. (a) Orbital energy level (orbital spin L1=0,L2=1); (b) fine structure energy level (electron spin S=1/2); (c) hyperfine structure energy level (nuclear spin I=3/2)
    Schematic diagram of atomic magnetometer principle
    Fig. 2. Schematic diagram of atomic magnetometer principle
    Basic response curves of atomic magnetometer. (a) Absorption curve (solid line); (b) dispersion curve (dashed line)
    Fig. 3. Basic response curves of atomic magnetometer. (a) Absorption curve (solid line); (b) dispersion curve (dashed line)
    Schematic diagram of CPT atomic clock principle. (a) Λ energy level configuration; (b) typical EIT absorption line type
    Fig. 4. Schematic diagram of CPT atomic clock principle. (a) Λ energy level configuration; (b) typical EIT absorption line type
    Relaxation mechanismPotentialTypical phenomenonTypical parameterReference
    Near field dipole moment interaction(DADB)-3DAR̂AB×R̂ABDBR-3Self-broadening of optical lines and self-depolarization of excited states;foreign gas broadeningResonant interaction cross section σDN ~10-13 cm247
    Radiation field dipole moment interaction(DAR̂ABR̂ABDB-3DADB)k2R-1Radiation trapping;coherence narrowingRelaxation times depend on container shape48
    Electron spin exchange interactionVR̂ABSASBApproach to spin temperature equilibrium;conservation of total spinInteraction cross section σDR ~10-14 cm249-50
    Coupling of electron spin to orbital spinVR̂NS

    Disorientation of S-state

    atoms by wall collisions

    and buffer-gas collisions

    Interaction cross section

    σLS ~10-19-10-26 cm2

    51
    Coupling of electron spin to nuclear spinST(R̂)IDisorientation of S-state atoms by wall collisions and buffer-gas collisions;nuclear polarization by spin exchange with electrons

    Interaction cross section

    σIS ~10-24 cm2

    52
    nuclear quadrupole moment16E:QWall relaxation of nuclear spins of diamagnetic atomsDepends on sticking time at wall,field gradients at wall,nuclear quadrupole moment,etc.53
    Random motion in an inhomogeneous magnetic fieldv(H×H)I|H|2Relaxation of 3He ground-state atomsDepends on field gradient and mean free path54-55
    Scattering of resonant light-emcpARelaxation of pumped atoms to polarized equilibrium stateTypical pumping times are on order of milliseconds or longer56
    Diffusion of atomsDiffusion rate is proportional to average free path and average velocity of atomSpatial motion of polarized atoms to container walls by random walk through a buffer gasA few milliseconds in a cm scale cell57
    Table 1. Physical mechanisms of various atomic relaxation processes[46]
    Atomic speciesHeating temperature /Sensitivity /(fTHzYearReference
    Potassium19010200266
    1800.54200316
    18020200971
    2000.16201072
    Rubidium1905201017
    140-1806-11201273
    1804201418
    15015201874
    17510201975
    Cesium10340200876
    12014201477
    Potassium & Rubidium1955201478
    2100.68201979
    Table 2. Parameters of SERF atomic magnetometers in different alkali atomic gas chambers
    TechnologyStabilityYearReference
    Vertically polarized light configuration combined with Ramsey time-domain separation method

    Short-term stability

    3×10-13τ-1/2,τ100 s

    201394
    Push-pull optical pumping combined with self-balancing Ramsey method10000 s stability 2×10-1520188895
    Table 3. Types and specifications of high-performance CPT atomic clocks
    YearSensitivityApplicationReference
    20052.9×10-5°/s/Hz1/2First realization of self-compensating SERF inertial measurement of nuclear spin96
    20094×10-6°/s/Hz1/2Measuring neutron spin-spin interactions97
    20104×10-6°/s/Hz1/2Highest index for verification of |b˜n| parameter of neutron charge conjugation-parity-time inversion symmetry breaking63
    20127×10-5°/s/Hz1/2Domestic first realization of SERF atomic spin gyro98
    Table 4. Performances and applications of SERF atomic spin gyroscope