Spectroscopic investigations of a waveguide for photon-echo quantum memory

Sinclair, Neil; Sağlamyürek, Erhan; George, Mathew; Ricken, Raimund; Mela, C. La; Sohler, W.; Tittel, Wolfgang

doi:10.1016/j.jlumin.2009.12.022

Cited by 58 publications

(127 citation statements)

References 86 publications

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“…We find at least one order of magnitude improvement of critical properties (optical coherence and hyperfine population lifetimes) compared to those measured previously in a similar waveguide at 3 K [18]. Moreover, the measured properties match those observed using Tm 3+ :LiNbO 3 bulk crystals under similar conditions [24], and improve upon those observed with other REIdoped waveguides [20][21][22].…”

supporting

confidence: 82%

“…x = 1. We find a coherence lifetime of 117 µs; 70 times greater than what we measured in Tm 3+ :Ti 4+ :LiNbO 3 at 3.5 K [18], and larger than the 86 µs we observed using a Tm 3+ :LiNbO 3 bulk crystal at 790 mK temperature, 794.25 nm wavelength, and ∼150 Gauss magnetic field [24]. The increase of T 2 with lower temperatures is due to a reduction of phonon-induced decoherence.…”

mentioning

confidence: 54%

“…Magnetic fields of up to 20 kG are applied parallel to the crystal's c-axis using a superconducting solenoid coil. We employ an external-cavity diode laser, producing polarized light set normal to the crystal's c-axis [18,19]. Its wavelength is tuned between 795.5 and 799.0 nm (vac.)…”

mentioning

confidence: 99%

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Properties of a Rare-Earth-Ion-Doped Waveguide at Sub-Kelvin Temperatures for Quantum Signal Processing

et al. 2017

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We characterize the 795 nm 3 H6 to 3 H4 transition of Tm 3+ in a Ti 4+ :LiNbO3 waveguide at temperatures as low as 800 mK. Coherence and hyperfine population lifetimes -up to 117 µs and 2.5 hours, respectively -exceed those at 3 K at least ten-fold, and are equivalent to those observed in a bulk Tm 3+ :LiNbO3 crystal under similar conditions. We also find a transition dipole moment that is equivalent to that of the bulk. Finally, we prepare a 0.5 GHz-bandwidth atomic frequency comb of finesse >2 on a vanishing background. These results demonstrate the suitability of rare-earthdoped waveguides created using industry-standard Ti-indiffusion in LiNbO3 for on-chip quantum applications.PACS numbers: 42.50. Md, 42.82.Gw, 42.50.Gy, 32.70.Cs Integrated optics offers the possibility of scalable manipulation of light due to small guiding volume, chip size, ever-improving fabrication methods, and low loss [1,2]. These attractive features have also enabled advanced experiments and applications of quantum optics and quantum information processing, with many demonstrations using telecommunication-industry-standard Tiindiffused LiNbO 3 waveguides, e.g. see [3][4][5][6][7][8][9] and references therein. Moreover, the ability to combine many components onto a single substrate is required for the implementation of an integrated quantum information processing node that performs local operations, interconnects, and measurements for quantum-secured computing and communications [10]. For example, a chip containing multiplexed sources of entangled photon pairs, Bell-state analyzers, photon number-resolving nondestructive photon detection, and feed-forward qubit-mode translation and selection, e.g. using frequency shifts or on-demand quantum memories, could pave the way to the development of a practical quantum repeater [9,11,12]. A promising avenue to this end, and to quantum information processing in general, is based on qubit interfaces using rare-earth-ion-doped (REI-doped) crystals at cryogenic temperatures [3,5,[12][13][14][15][16]. Consequently, the development of rare-earth-ion-doped waveguides constitutes an exciting and important path towards applications.Many ground-breaking quantum optics experiments, in particular quantum memory for light [13][14][15][16], are based on cryogenically-cooled REIs doped into a variety of bulk crystals. However, work employing REI-doped crystalline waveguides has, until only the past year, been restricted to LiNbO 3 -generally doped with thulium -into which waveguides were fabricated by means of titanium indiffusion [3,5,9,12,17]. A likely explanation for the lack of investigations using other REIs in Ti 4+ :LiNbO 3 is that an earlier low-temperature characterization of -all of which guide light in unperturbed regions of the REI-doped crystal. While the results are promising, it is still unclear how the waveguide fabrication process affects the relevant REI properties for quantum applications and if good properties can be retained using industry-standard Ti-indiffusion in LiNbO 3 .To investi...

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confidence: 82%

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confidence: 54%

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Properties of a Rare-Earth-Ion-Doped Waveguide at Sub-Kelvin Temperatures for Quantum Signal Processing

et al. 2017

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“…In the literature, this lifetime was reported to be 2.45 ms by a direct measurement of the 1.7 µm transition in bulk crystals 37 and waveguides. 38,39 The differences are quite significant and need further explanation, especially considering that this lifetime is essentially concentration independent. 37 We think the different measurements may be sampling different groups of ions in the material, resulting in the the different values of the bottleneck lifetime.…”

Section: Summary and Discussionmentioning

confidence: 97%

Optical decoherence and energy level structure of 0.1%Tm3+:LiNbO3

2012

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We report the energy level structure of the 3 H6 and 3 H4 multiplets for Tm 3+ doped congruent LiNbO3, as well as the decoherence properties and their temperature dependencies for the 3 H6(1) ↔ 3 H4(1a) transition at 794 nm. It is shown that this material provides very significant improvements in bandwidth, time-bandwidth product, and sensitivity for spatial-spectral holographic signal processing devices and quantum memories based on spectral hole burning. The available signal processing bandwidth for 0.1% Tm 3+ :LiNbO3 is 300 GHz versus 20 GHz for Tm 3+ YAG. The peak absorption coefficient for 0.1% Tm 3+ :LiNbO3 is 15 cm −1 at 794.5 nm compared with 1.7 cm −1 for 0.1% Tm:YAG at 793 nm, and the total absorption strength is eighty times stronger. The oscillator strength for Tm 3+ :LiNbO3 is about twenty five times larger than that for Tm 3+ :YAG, making the material five times more sensitive for processing high-bandwidth analog signals. The homogeneous linewidth, which determines processing time or spectrum analyzer resolution, is 30 kHz at 1.6 K and 350 kHz at 6 K, as measured by photon echoes. Those values establish potential time-bandwidth products of 10 7 and 7 ×10 5 respectively. The temperature dependence of the homogeneous linewidth was explained by observation of a 7.8 cm −1 crystal field level in the ground multiplet and direct phonon coupling. The excited state 3 H4 lifetime T1 is 152 µs and the bottleneck lifetime of the lowest 3 F4 level is 7 ms from photon echo measurements. These factors combine to provide a surprisingly large increase in key parameters that determine material performance for spatial-spectral holography, quantum information, and other spectral hole burning applications.

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“…On the other hand, for a certain type of dopant, by having the external electric field orthogonal to the difference between the permanent electric dipole moment of the ground and excited states, one can keep the resonant frequency between these states unchanged. In our proposed system the permanent dipoles are aligned with the 3-axis [20,21], therefore the electric field should be applied along the 2-axis in order to avoid level shifts.…”

Section: Possible Implementationmentioning

confidence: 99%

Photonic quantum memory in two-level ensembles based on modulating the refractive index in time: Equivalence to gradient echo memory

2012

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We present a quantum memory protocol that allows to store light in ensembles of two-level atoms, e.g. rare-earth ions doped into a crystal, by modulating the refractive index of the host medium of the atoms linearly in time. We show that under certain conditions the resulting dynamics is equivalent to that underlying the gradient echo memory protocol, which relies on a spatial gradient of the atomic resonance frequencies. We discuss the prospects for an experimental implementation.

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Spectroscopic investigations of a waveguide for photon-echo quantum memory

Cited by 58 publications

References 86 publications

Properties of a Rare-Earth-Ion-Doped Waveguide at Sub-Kelvin Temperatures for Quantum Signal Processing

Properties of a Rare-Earth-Ion-Doped Waveguide at Sub-Kelvin Temperatures for Quantum Signal Processing

Optical decoherence and energy level structure of 0.1%Tm3+:LiNbO3

Photonic quantum memory in two-level ensembles based on modulating the refractive index in time: Equivalence to gradient echo memory

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