| 1. |
- Alqedra, Mohammed K., et al.
(författare)
-
Optical coherence properties of Kramers' rare-earth ions at the nanoscale for quantum applications
- 2023
-
Ingår i: Physical Review B. - 2469-9950. ; 108:7
-
Tidskriftsartikel (refereegranskat)abstract
- Rare Earth (RE) ion doped nanomaterials are promising candidates for a range of quantum technology applications. Among RE ions, the so-called Kramers' ions possess spin transitions in the GHz range at low magnetic fields, which allows for high-bandwidth multimode quantum storage, fast qubit operations as well as interfacing with superconducting circuits. They also present relevant optical transitions in the infrared. In particular, Er3+ has an optical transition in the telecom band, while Nd3+ presents a high-emission-rate transition close to 890 nm. In this paper, we measure spectroscopic properties that are of relevance to using these materials in quantum technology applications. We find the inhomogeneous linewidth to be 10.7 GHz for Er3+ and 8.2 GHz for Nd3+, and the excited state lifetime T1 to be 13.68 ms for Er3+ and 540μs for Nd3+. We study the dependence of homogeneous linewidth on temperature for both samples, with the narrowest linewidth being 379 kHz (T2=839 ns) for Er3+ measured at 3 K, and 62 kHz (T2=5.14μs) for Nd3+ measured at 1.6 K. Further, we investigate time-dependent homogeneous linewidth broadening due to spectral diffusion and the dependence of the homogeneous linewidth on magnetic field to get additional clarity of mechanisms that can influence the coherence time. In light of our results, we discuss two applications: single qubit-state readout and a Fourier-limited single photon source.
|
|
| 2. |
- Andersson-Engels, Stefan, et al.
(författare)
-
Deep-tissue optical imaging and photoactivation activities at biophotonics@tyndall
- 2016
-
Ingår i: Frontiers in Optics, FiO 2016. - 2162-2701. - 9781943580194
-
Konferensbidrag (refereegranskat)abstract
- Activities for deep tissue imaging and photoactivation will be presented. Wihin Biophotonics@Tyndall projects based on upconverting nanoparticles and ultrasound optical tomography will be pursued. Data from collaborative research will be given.
|
|
| 3. |
- Bartholomew, John G., et al.
(författare)
-
High-resolution spectroscopic techniques for studying rare-earth ions in nanoparticles
- 2023
-
Ingår i: Journal of Luminescence. - : Elsevier BV. - 0022-2313. ; 257
-
Tidskriftsartikel (refereegranskat)abstract
- Rare-earth doped nanoparticles can exhibit narrow optical and spin linewidths at low temperatures. These outstanding properties for nanomaterials make them attractive for quantum technologies based on optically addressable spins such as quantum memories and computers. Although accurate linewidth measurements have been reported using, for example, spectral hole burning or photon echo techniques, so far they have been mostly restricted to large ensembles of particles. Being able to extend linewidths measurements to few and single particles is particularly important in view of their integration in nanophotonic devices. In this paper, we present techniques for determining inhomogeneous and homogeneous linewidths of small ensembles of rare-earth ions in doped nanoparticles with high signal-to-noise ratios for convenient integration times. Using these techniques we have observed property variations for particles from the same synthesis, a first step towards their optimization for applications in quantum technologies.
|
|
| 4. |
- Bengtsson, Alexander, et al.
(författare)
-
Characterization and modeling of acousto-optic signal strengths in highly scattering media
- 2019
-
Ingår i: Biomedical Optics Express. - 2156-7085. ; 10:11, s. 5565-5584
-
Tidskriftsartikel (refereegranskat)abstract
- Ultrasound optical tomography (UOT) is an imaging technique based on the acousto-optic effect that can perform optical imaging with ultrasound resolution inside turbid media, and is thus interesting for biomedical applications, e.g. for assessing tissue blood oxygenation. In this paper, we present near background free measurements of UOT signal strengths using slow light filter signal detection. We carefully analyze each part of our experimental setup and match measured signal strengths with calculations based on diffusion theory. This agreement between experiment and theory allows us to assert the deep tissue imaging potential of similar to 5 cm for UOT of real human tissues predicted by previous theoretical studies [Biomed. Opt. Express 8, 4523 (2017)] with greater confidence, and indicate that future theoretical analysis of optimized UOT systems can be expected to be reliable. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement
|
|
| 5. |
- Bengtsson, Alexander, et al.
(författare)
-
Comparison of contrast-to-noise ratios of different detection methods in ultrasound optical tomography
- 2022
-
Ingår i: Biomedical Optics Express. - 2156-7085. ; 13:9, s. 4834-4850
-
Tidskriftsartikel (refereegranskat)abstract
- Ultrasound optical tomography (UOT) is a hybrid imaging modality based on interaction between ultrasound and light, with a potential to extend optical imaging capabilities in biological tissues to depths of several centimeters. Several methods have been developed to detect the UOT signal. To better understand their potential for deep tissue imaging, we present a theoretical contrast-to-noise comparison between the spectral hole burning, single-shot off-axis holography, speckle contrast, and photorefractive detection methods for UOT. Our results indicate that spectral hole burning filters have the potential to reach the largest imaging depths. We find that digital off-axis holography and photorefractive detection can have good contrast-to-noise ratio at significant depths. The speckle contrast method has a smaller penetration depth comparatively.
|
|
| 6. |
- Bengtsson, Samuel N., et al.
(författare)
-
Free induction decay in the extreme ultraviolet
- 2015
-
Ingår i: Proceedings of Frontiers in Optics 2015, FIO 2015. - 9781943580033
-
Konferensbidrag (refereegranskat)abstract
- We present an experimental study of controlled Free Induction Decay (FID) in the extreme ultraviolet regime excited by High-order Harmonics. The control is done by applying a delayed infrared pulse.
|
|
| 7. |
- Bondza, Saskia, et al.
(författare)
-
A simple experimental method for measuring the thermal sensitivity of single-mode fibers
- 2020
-
Ingår i: Review of Scientific Instruments. - : AIP Publishing. - 0034-6748 .- 1089-7623. ; 91:10
-
Tidskriftsartikel (refereegranskat)abstract
- We present a simple technique to experimentally determine the optical-path length change with temperature for optical single-mode fibers. Standard single-mode fibers act as natural low-finesse cavities, with the Fresnel reflection of the straight cleaved surfaces being ∼3%, for the laser light coupled to them. By measuring the intensity variations due to interference of light reflected from the fiber front and end surfaces, while ramping the ambient temperature, the thermal sensitivity of the optical-path length of the fiber can be derived. Light was generated by a narrow linewidth, low drift laser. With our fairly short test fibers, we found that it was possible to reach a relative precision of the temperature sensitivity, compared to a reference fiber, on the 0.4%-2% scale and an absolute precision of 2%-5%, with the potential to improve both by an order of magnitude. The results for single-acrylate, dual-acrylate, and copper- and aluminum-coated fibers are presented. Values are compared with analytic models and results from a finite element method simulation. With the aid of these measurements, a simple fiber-interferometer, which is insensitive to thermal drifts, could be constructed.
|
|
| 8. |
- Goldner, Ph., et al.
(författare)
-
Long coherence lifetime and electromagnetically induced transparency in a highly-spin-concentrated solid
- 2009
-
Ingår i: Physical Review A (Atomic, Molecular and Optical Physics). - 1050-2947. ; 79:3
-
Tidskriftsartikel (refereegranskat)abstract
- We have studied a rare-earth-doped crystal, Pr3+:La-2(WO4)(3), which exhibits a high magnetic-moment density. Although the latter favors rare-earth dephasing, a nuclear-spin coherence lifetime of 250 mu s has been observed, as well as electromagnetically induced transparency (EIT). This suggests that a broad range of materials could be considered for quantum information applications such as quantum memories for light, where solids are especially attractive. Absorption and dispersion curves are independently in very good agreement with EIT theory. Fano-like profiles have also been observed.
|
|
| 9. |
- Guillot-Noel, O., et al.
(författare)
-
Hyperfine structure and hyperfine coherent properties of praseodymium in single-crystalline La-2(WO4)(3) by hole-burning and photon-echo techniques
- 2009
-
Ingår i: Physical Review B (Condensed Matter and Materials Physics). - 1098-0121. ; 79:15
-
Tidskriftsartikel (refereegranskat)abstract
- We studied the hyperfine structure and hyperfine coherent properties of the H-3(4)(0)-> D-1(2)(0) transition of Pr3+ ions in a tungstate single crystal La-2(WO4)(3) by hole-burning and photon-echo techniques. This work is motivated by the search of an efficient three level Lambda system in this new compound with which we could build up a quantum memory. By nonconventional hole-burning experiments, the ordering of the hyperfine splittings in the H-3(4)(0) ground state and in the D-1(2)(0) excited state is obtained. The hyperfine splittings are thus ordered: 24.6 and 14.9 MHz for the H-3(4)(0) level and 5.0 and 7.3 MHz for the D-1(2)(0) level. The relative and absolute transition strengths of individual hyperfine transitions are determined by comparing absorption strengths and by measuring the Rabi flopping frequency as the transition is coherently driven. Free induction and Raman echo decays give inhomogeneous and homogeneous hyperfine linewidths of 57 +/- 2 and 1.25 +/- 0.1 kHz, respectively.
|
|
| 10. |
- Guillot-Noel, O., et al.
(författare)
-
Hyperfine structure, optical dephasing, and spectral-hole lifetime of single-crystalline Pr3+: La-2(WO4)(3)
- 2007
-
Ingår i: Physical Review B (Condensed Matter and Materials Physics). - 1098-0121. ; 75:20
-
Tidskriftsartikel (refereegranskat)abstract
- Most of the experiments related to quantum information applications, involving rare-earth doped inorganic crystals, are performed on yttrium orthosilicate single crystals. The work presented here is motivated by the search of new compounds which can be used in the field of quantum computing and/or quantum storage. Relaxation times and hyperfine structure of the H-3(4)(0)-> D-1(2)(0) transition in 1.4% Pr3+:La-2(WO4)(3) at 4 K have been measured by photon-echo and spectral-hole-burning techniques. The hyperfine splittings of the ground H-3(4)(0) and the excited D-1(2)(0) states are 14.9 +/- 0.1 MHz, 24.6 +/- 0.1 MHz and 5.0 +/- 0.1 MHz, 7.3 +/- 0.1 MHz, respectively. An inhomogeneous linewidth of 18.8 +/- 0.1 GHz was measured. A homogeneous linewidth of 25.3 +/- 2.0 kHz was obtained with or without an external magnetic field of about 14 mT. The fluorescence dynamics of the D-1(2) level obtained by a direct excitation in the H-3(4)-> D-1(2) transition gives a nonexponential decay which indicates energy-transfer processes. This decay can be accurately fitted by the Inokuti-Hirayama model [J. Chem. Phys. 43, 1978 (1965)] with a radiative lifetime of 61 +/- 1 mu s giving a minimal homogeneous linewidth of 2.6 kHz. The spectral-hole lifetime due to population redistribution within the ground hyperfine levels is 16 +/- 2 s. The results obtained for the La-2(WO4)(3) compound make this crystal an interesting host for quantum applications.
|
|
