Two-photon spectroscopy of trapped HD${}^{+}$ ions in the Lamb-Dicke regime

Abstract

We study the feasibility of nearly-degenerate two-photon rovibrational spectroscopy in ensembles of trapped, sympathetically cooled hydrogen molecular ions using a resonance-enhanced multiphoton dissociation (REMPD) scheme. Taking advantage of quasi-coincidences in the rovibrational spectrum, the excitation lasers are tuned close to an intermediate level to resonantly enhance two-photon absorption. Realistic simulations of the REMPD signal are obtained using a four-level model that takes into account saturation effects, ion trajectories, laser frequency noise and redistribution of population by blackbody radiation. We show that the use of counterpropagating laser beams enables optical excitation in an effective Lamb-Dicke regime. Sub-Doppler lines having widths in the 100 Hz range can be observed with good signal-to-noise ratio for an optimal choice of laser detunings. Our results indicate the feasibility of molecular spectroscopy at the $10^{-14}$ accuracy level for improved tests of molecular QED, a new determination of the proton-to-electron mass ratio, and studies of the time (in)dependence of the latter.

16 pages, 17 figures

References in corpus (8)

• Enhanced sensitivity to variation of the fine structure constant and m_p/m_e in diatomic molecules
• Stability of the proton-to-electron mass ratio
• Bounds on fifth forces from precision measurements on molecules
• Calculation of the relativistic Bethe logarithm in the two-center problem
• Vibrational spectroscopy of H2+: hyperfine structure of two-photon transitions
• Relativistic corrections of mα^6(m/M) order to the hyperfine structure of the H_2^+ molecular ion
• Vibrational spectroscopy of H2+: precise evaluation of the Zeeman effect
• Nuclear-spin dependent parity violation in diatomic molecular ions

Cited by in corpus (13)

• Probing QED and fundamental constants through laser spectroscopy of vibrational transitions in HD+
• Proton-Electron Mass Ratio from Laser Spectroscopy of HD${}^{+}$ at the Part-Per-Trillion Level
• Fundamental transitions and ionization energies of the hydrogen molecular ions at the few ppt level
• Constraints on extra dimensions from precision molecular spectroscopy
• H2+ and HD+: candidates for a molecular clock
• Hydrogen molecular ions for improved determination of fundamental constants
• Hyperfine structure in the H${}_2^{+}$ and HD${}^{+}$ molecular ions at $m{\alpha }^6$ order
• High-precision spectroscopy of the HD+ molecule at the 1-p.p.b. level
• Proton-electron mass ratio from HD${}^{+}$ revisited
• One-loop vacuum polarization at m$\alpha$7 and higher orders for three-body molecular systems
• Proposal for suppressing ac Stark shift in the He($2{}^3{S}_1\to 3{}^3{S}_1$) two-photon transition using magic wavelengths
• Physics beyond the Standard Model from hydrogen spectroscopy
• Ghost features in Doppler-broadened spectra of rovibrational transitions in trapped HD${}^{+}$ ions