A Single-Ion Reservoir as a High-Sensitive Sensor of Electric Signals

Abstract

A single-ion reservoir has been tested, and characterized in order to be used as a highly sensitive optical detector of electric signals arriving at the trapping electrodes. Our system consists of a single laser-cooled 40Ca+ ion stored in a Paul trap with rotational symmetry. The performance is observed through the axial motion of the ion, which is equivalent to an underdamped and forced oscillator. Thus, the results can be projected also to Penning traps. We have found that, for an ion oscillator temperature T axial ≲ 10 mK in the forced-frequency range ω z = 2π × (80,200 kHz), the reservoir is sensitive to a time-varying electric field equivalent to an electric force of 5.3(2) neV/μm, for a measured quality factor Q = 3875(45), and a decay time constant γ z = 88(2) s−1. This method can be applied to measure optically the strength of an oscillating field or induced (driven) charge in this frequency range within times of tens of milliseconds. Furthermore the ion reservoir has been proven to be sensitive to electrostatic forces by measuring the ion displacement. Since the heating rate is below 0.3 μeV/s, this reservoir might be used as optical detector for any ion or bunch of charged particles stored in an adjacent trap.

Phonon-laser ultrasensitive force sensor

“…In addition, squeezing technique [17] was employed to further suppress thermal noises in the system. The ion's phonon laser under our consideration works as an amplitude-amplified harmonic oscillator, which is quite sensitive to the external force, as reported previously [18][19][20][21][22][23]. In our experiment, the trapped 40 Ca + ion was first Doppler-cooled and then pumped simultaneously by a red-detuned laser and a blue-detuned laser with respect to the resonant transition.…”

The TRAPSENSOR facility: an open-ring 7 tesla Penning trap for laser-based precision experiments

“…The resonant transition 1 S  0 1 P 1 (Δm j =+1) has been used (422 nm). The frequency for this transition is 98GHz above the value used in the Paul trap experiments [22], due to the confinement of the ion in the 7 tesla magnetic field.…”

“…The main scientific goal of the TRAPSENSOR Penning-traps facility is to use a single laser-cooled 40 Ca + ion as high-sensitive sensor for precision Penning-trap mass spectrometry [19]. The characterization of a single laser-cooled 40 Ca + ion was accomplished using a Paul trap [22], including the scenario with two ions in the trap [23].…”

“…Besides the on-going developments of a variant of the induced-image current technique for SHEs [5,18], a novel method for mass spectrometry was proposed based on the use of a single laser-cooled 40 Ca + ion as detector [19], following a scheme based on two traps described earlier [20]. In the first ever attempt to experimentally realize this concept, the sensitivity of a single 40 Ca + ion laser-cooled to the Doppler limit (T 1 limit mK) has been characterized by studying its axial motion in an open-ring Paul trap [21,22]. The analytical method and a first approach of using just one trap to store the ion of interest and the laser-cooled ion simultaneously has been recently presented [23], following a former idea described in [24].…”

Dynamics of an unbalanced two-ion crystal in a Penning trap for application in optical mass spectrometry

“…The outcomes from the calculations can be combined with the optical response of the sensor ion after applying external fields in resonance with the motional modes of the crystal. The latter has already been studied using a Paul trap with rotational symmetry [14,15]. The proposed method is universal (with respect to the massto-charge ratio), it can be used in broad band mode, and offers a permanent monitoring of the motion of the sensor ion in the trap, allowing for a precise quantification of possible systematic effects arising from trap-electrodes imperfections or misalignments with respect to the magnetic field.…”