A single laser system for ground-state cooling of 25Mg+

Hemmerling, Boerge; Gebert, Florian; Wan, Yong; Nigg, Daniel; Sherstov, I.; Schmidt, Piet O.

doi:10.1007/s00340-011-4444-0

Cited by 31 publications

(35 citation statements)

References 38 publications

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“…We use a hyperfine qubit consisting of the states |↓ Mg = |F = 3, m F = 3 and |↑ Mg = |F = 2, m F = 2 of the 2 S 1/2 electronic ground state. The Raman laser system for coherent manipulation of the 25 Mg + qubit via the 2 P 3/2 Level is based on a frequency-quadrupled fiber laser 31 . The detuning from the atomic resonance is fixed at 9.2 GHz, limiting ground state cooling efficiency 27 and qubit operations due to spontaneous Raman scattering 32 .…”

Section: Methodsmentioning

confidence: 99%

Non-destructive state detection for quantum logic spectroscopy of molecular ions

Wolf

Wan

Heip

et al. 2016

Nature

179

168

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Precision laser spectroscopy 1 of cold and trapped molecular ions is a powerful tool for fundamental physics, including the determination of fundamental constants 2 , the laboratory test for their possible variation 3,4 , and the search for a possible electric dipole moment of the electron 5 . While the complexity of molecular structure facilitates these applications, the absence of cycling transitions poses a challenge for direct laser cooling 6 , quantum state control [7][8][9][10][11] , and detection. Previously employed state detection techniques based on photodissociation 12 or chemical reactions 13 are destructive and therefore inefficient, restricting the achievable resolution in laser spectroscopy. Here we experimentally demonstrate nondestructive state detection of a single trapped molecular ion through its strong Coulomb coupling to a well-controlled co-trapped atomic ion. An algorithm based on a state-dependent optical dipole force 14 (ODF) changes the internal state of the atom conditioned on the internal state of the molecule. We show that individual quantum states in the molecular ion can be distinguished by their coupling strength to the ODF and observe black-body radiationinduced quantum jumps between rotational states of a single molecular ion. Using the detuning dependence of the state detection signal, we implement a variant of quantum logic spectroscopy 15,16 of a molecular resonance. The state detection technique we demonstrate is applicable to a wide range of molecular ions, enabling further applications in state-controlled quantum chemistry 17 and spectroscopic investigations of molecules serving as probes for interstellar clouds 18,19 .One of the salient features of trapped ion systems is that the universal Coulomb interaction allows strong coupling of diverse quantum objects, such as different species of atomic ions or atomic and molecular ions. Being able to perform quantum logic operations e.g. in the form of gates 14,20,21 between the quantum objects has proven a powerful tool for quantum information processing and quantum simulations in such systems. It also allows combining the advantages of different atomic species. Quantum logic spectroscopy is one such application in which the high degree of control achieved over selected atomic ions is extended to species over which such control is lacking 15,16 . Here, we demonstrate for the first time quantum logic operations between a single molecular ion and a co-trapped atomic ion, making a wide range of molecular ions accessible to this highlydeveloped toolbox. The presented technique allows the investigation of single molecules in a well isolated system avoiding disturbance from the environment, which is the limiting factor in other implementations of single molecule spectroscopy such as surface enhanced Raman spectroscopy (SERS) 22 Quantum logic operations between atoms are based on state dependent forces often induced by laser fields. The same approach is applicable to molecular ions. The coupling is now distributed over many ro-vibrat...

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Section: Methodsmentioning

confidence: 99%

Non-destructive state detection for quantum logic spectroscopy of molecular ions

Wolf

Wan

Heip

et al. 2016

Nature

179

168

View full text Add to dashboard Cite

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“…The beams have tc and a + polarization to maximize the coupling strength and are at right angles to each other with the difference wave vector aligned along the axial direction of the trap. This results in a Lamb-Dicke parameter of r] = 0.3 [67] for the axial mode of interest here. The limited detuning of the Raman laser beams leads to off-resonant excitations, which result in dephasing and population loss during coherent manipulation as further discussed in Sec.…”

Section: A Experimental Setupmentioning

confidence: 97%

“…Compared to an extension of the SBC scheme de scribed in Ref. [67] to two-mode ground-state cooling, the op timized new scheme reduces the cooling time by a factor of 8.…”

Section: Time Scaling Factor Optimizationmentioning

confidence: 98%

“…In the previously implemented SBC scheme [67] the Rabi frequency £2,,-" of the Raman transition between motional state |n) and |ri) was calculated according to [58,63] Q n',n = exp (1) where is the CAR Rabi frequency, n< («>) denotes the smaller (larger) of n,n', and L°(x) are the generalized Laguerre polynomials. This allowed the determination of the n time for complete population transfer on the first-and second-order RSBs (see Fig.…”

Section: A Experimental Setupmentioning

confidence: 99%

“…Doppler cooling and Raman transitions are performed by coupling the 2S 1/2 and2 P3/2 states. Compared to aprevious implementation of SBC [67], a second laser is added for repumping the |aux) state via the 2Si/2 •<-> 2P]/2 transition, rf radiation couples the states |f) and |aux).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Efficient sympathetic motional-ground-state cooling of a molecular ion

et al. 2015

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Cold molecular ions are promising candidates in various fields ranging from precision spectroscopy and test of fundamental physics to ultracold chemistry. Control of internal and external degrees of freedom is a prerequisite for many of these applications. Motional-ground-state cooling represents the starting point for quantum logic-assisted internal state preparation, detection, and spectroscopy protocols. Robust and fast cooling is crucial to maximize the fraction of time available for the actual experiment. We optimize the cooling rate of ground-state cooling schemes for single 25Mg+ ions and sympathetic ground-state cooling of 24MgH+. In particular, we show that robust cooling is achieved by combining pulsed Raman sideband cooling with continuous quench cooling. Furthermore, we experimentally demonstrate an efficient strategy for ground-state cooling outside the Lamb-Dicke regime.

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A self-injection locked DBR laser for laser cooling of beryllium ions

et al. 2018

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We present a simple, robust, narrowlinewidth, frequency-doubled semiconductor laser source suitable for laser cooling and repumping of 9 Be + ions. A distributed Bragg reflector (DBR) laser diode operating at 626 nm is self-injection-locked to a frequency doubling cavity via phase-stabilised optical feedback when the laser is resonant with the cavity mode. The short-term laser instability is reduced from the MHz-level to approximately 20 kHz by the injection process, thus eliminating the need for a high-bandwidth feedback loop to suppress the otherwise troublesome high-frequency laser noise. Long-term stability of the laser frequency is achieved by feeding back to the length of the enhancement cavity utilising an electro-optic frequency comb generator to produce a beatnote with a laser that is detuned by 98 GHz. Long-term injection locking and frequency stabilisation via a wavemeter are ensured using automatic relocking algorithms.

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A single laser system for ground-state cooling of 25Mg+

Cited by 31 publications

References 38 publications

Non-destructive state detection for quantum logic spectroscopy of molecular ions

Non-destructive state detection for quantum logic spectroscopy of molecular ions

Efficient sympathetic motional-ground-state cooling of a molecular ion

A self-injection locked DBR laser for laser cooling of beryllium ions

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