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Item Rare earth doped crystals for classical and quantum information(Montana State University - Bozeman, College of Letters & Science, 2021) Woodburn, Philip Joseph 'Tino'; Chairperson, Graduate Committee: Rufus L. Cone; This is a manuscript style paper that includes co-authored chapters.High-quality rare-earth-ion (REI) doped materials are a prerequisite for many applications such as quantum memories, ultra-high-resolution photonic signal processing, and quantum-limited sensing. Realization of practical solid-state photonic technologies critically depends on finding materials that offer necessary combinations of optical and spin-state coherence, spectral multiplexing capacity, transition wavelengths, and many other key properties. To realize these advances, we continue to improve the fundamental understanding and control of physical processes that govern ion-ion, ion-spin, and ion-lattice interactions. Furthermore, exploring the role of material chemistry and fabrication in determining the observed properties is crucial. With these motivations, we study a range of rare-earth-doped optical materials using powders and single crystals to understand and optimize the properties relevant to quantum memory, quantum transduction, photonic signal processing, and optical cooling applications. In addition to producing, measuring, and analysing spectroscopic and coherence properties of promising material systems, we highlight the engineering of lattice defects to manipulate both static and dynamic disorder. This work spans nine different REI doped materials: four single crystals, Tm 3+:Y 3Ga 5O 12, Yb 3+:YVO 4, Er 3+:Y 3Al 5O 12, and Er 3+:Y 2SiO 5, and five crystalline powders, Er 3+:LiNbO 3, Tm 3+:Y 3Al 5O 12, Tb 3+:Y 3Al 5O 12, Yb 3+:YAG, and Eu 3+:CaCO 3. These choices are based on material properties unique to each system, need for investigation, or potential for systematic comparison of fabrication methods and stoichiometry. Spectral hole burning (SHB), optical and spin coherence measurement techniques are sensitive quantitative characterization tools, complementing traditional optical, chemical, and structural analysis. We find that coherence and spin lifetimes are especially sensitive to low levels of strain and defects in the crystal, undetected by other methods. Properties of REI doped materials are found to vary by orders of magnitude depending on the source, synthesis, and implementation of the materials. Even mild mechanical processing producing large variations in spin lifetimes and SHB properties. These variations are attributed to low levels of glass-like dynamics in the crystalline lattice introduced by inhomogeneous strain and chemical defects, which can be reduced or eliminated by annealing or improved fabrication. Overall, these studies reveal that SHB or coherence measurements are needed to identify material dynamics and guide the fabrication process to reach the true fundamental capabilities of REI materials.Item Exploration of rare-earth ion transitions and host materials for spectral hole burning applications and quantum information science(Montana State University - Bozeman, College of Letters & Science, 2021) Marsh, Aaron Daniel; Chairperson, Graduate Committee: Rufus L. ConeDue to their capacity for generating and manipulating light, the rare-earths are a foundational part of many cutting-edge technologies, ranging from lighting to quantum communications. Optical applications based on rare-earth doped materials are restricted to their transition energies. There are large bands, including the telecom window, where available rare-earth transitions typically have poor properties at liquid helium temperatures. The limitations are determined by the fundamental interactions between rare-earth ions and their host materials; comprehension of the interactions can be leveraged to significantly improve the properties of rare-earth quantum states. Three unexplored rare-earth optical transitions are investigated in this thesis: the Tm 3+ 3 H6<-->3 F3 at ~690 nm, the Pr 3+ 3 H 4<-->3 F 3 at ~1584 nm, and the Tm 3+ 3 F4<-->3 H 4 at ~1451 nm. The first transition suppresses non-radiative relaxation through engineering of the host material phonon spectrum. The 3 F 3 lifetime is extended to ~100 microsecond in Tm 3+ :KPb 2Br 5. The material Tm 3+:LaF 3 is also prepared for high-contrast spectral filtering in ultrasound-optical medical imaging sensitive to blood oxygenation at ~690 nm. Narrow 380 kHz holes are burned; simulations of hole burning indicate that ~60 dB of filtering contrast at ~3MHz is possible. Likewise, non-radiative relaxation is suppressed on the Pr 3+ transition at ~1584 nm in the low-phonon energy host RbPb 2Br 5. Four sites are revealed, with ~2-5 GHz spectrally resolved inhomogeneous broadenings, ~0.5-1 ms T 1 lifetimes, pseudoquadrupole level storage, and ~750 ns coherence times. This material is discussed for use as an L-band quantum memory. The excited state transition of Tm 3+ at ~1451 nm is then explored for quantum memories. High-resolution spectroscopy finds ~1 GHz inhomogeneous broadenings, ~6 ms lifetimes, and laser-limited ~30 MHz holes are burned. Techniques for measuring the properties of excited state transitions are described. Throughout, experimental methods and applications demonstrate the close relationship between lanthanide research and devices. Rare-earth doped crystals are used as an all-optical, high-resolution sensor package for characterizing cryostats in situ, and spectral hole burning characterizes laser performance as a real-time, ~1 MHz resolution spectrum analyzer. The exploration of rare-earth transitions is found to enable new research and new applications, with many other transitions yet to be explored.Item Two-step excitation and direct two-photon absorption in Tb 3+: LiYF 4(Montana State University - Bozeman, College of Letters & Science, 1990) Jones, Raymond PaulItem Photon echo studies of rare-earth-activated materials for optical memory and signal processing devices(Montana State University - Bozeman, College of Letters & Science, 1995) Equall, Randy WayneItem Optical characterization of perturbed sites and C₃i sites in rare earth doped oxide crystals(Montana State University - Bozeman, College of Letters & Science, 2003) Reinemer, Gregory DonaldItem Two-photon absorption and two-photon-resonant four-wave mixing for the Tb^3+ ion in insulators(Montana State University - Bozeman, College of Letters & Science, 1987) Huang, JinItem Thulium ions in a yttrium aluminum garnet host for quantum computing applications : material analysis and single qubit operations(Montana State University - Bozeman, College of Letters & Science, 2008) Zafarullah, Ijaz; Chairperson, Graduate Committee: Wm. Randall BabbittRare-earth-doped crystals have been used for optical signal processing and storage applications. In this dissertation, their potential for quantum computing applications is explored. In one quantum computing scheme, information is stored in nuclear spin states and this information is then processed by using optical pulses through the coupling of these nuclear spin states to a common electronic level. To implement this scheme, nuclear spin states and coupling of these nuclear spin states to a common electronic level is required. Preliminary work in rare-earth materials like Pr3+ and Eu3+ has shown promising results regarding their suitability for quantum computing applications. One particular problem with these materials is that their transition wavelengths are only accessible with dye lasers. These lasers are inherently unstable, and currently few available systems exhibit the stability required for quantum computing applications. An alternative choice was to investigate other rare-earth ions like thulium. Thulium has a transition wavelength that can be accessed with diode lasers, which are commercially available, easy to stabilize, and compact. This dissertation is based on our investigations of Tm3+:YAG for quantum computing applications. Investigations involved a detailed characterization of the material. Nuclear spin states, in Tm3+:YAG, were obtained by applying an external magnetic field to the sample. First, interaction of an external magnetic field with the thulium ions at various sites in the crystal was analyzed. This analysis was used to measure the magnetic anisotropy in the material. These results show that it is possible, with the suitable choice of the magnetic orientation and the site in the crystal, to build a working 3-level quantum system. In the demonstration of single qubit operations in Tm3+:YAG, we first theoretically studied the effect of Gaussian spatial beam on the single qubit operations. Later on, we experimentally prepared a single isolated ensemble of ions in the inhomogeneously broadened absorption profile of the medium. This single isolated ensemble of ions was used as a test-bed to implement the single qubit operations. We also isolated two ensembles of ions in the inhomogeneous absorption profile of the medium. The interaction between these two isolated ensembles of ions was also studied.Item Energies of rare-earth ion states relative to host bands in optical materials from electron photoemission spectroscopy(Montana State University - Bozeman, College of Letters & Science, 2003) Thiel, Charles Warren; Chairperson, Graduate Committee: Rufus L. Cone; John L. Carlsten (co-chair)There are a vast number of applications for rare-earth-activated materials and much of today's cutting-edge optical technology and emerging innovations are enabled by their unique properties. In many of these applications, interactions between the rare-earth ion and the host material's electronic states can enhance or inhibit performance and provide mechanisms for manipulating the optical properties. Continued advances in these technologies require knowledge of the relative energies of rare-earth and crystal band states so that properties of available materials may be fully understood and new materials may be logically developed. Conventional and resonant electron photoemission techniques were used to measure 4f electron and valence band binding energies in important optical materials, including YAG, YAlO3, and LiYF4. The photoemission spectra were theoretically modeled and analyzed to accurately determine relative energies. By combining these energies with ultraviolet spectroscopy, binding energies of excited 4f N-15d and 4f N+1 states were determined. While the 4f N ground-state energies vary considerably between different trivalent ions and lie near or below the top of the valence band in optical materials, the lowest 4f N-15d states have similar energies and are near the bottom of the conduction band. As an example for YAG, the Tb3+ 4f N ground state is in the band gap at 0.7 eV above the valence band while the Lu3+ ground state is 4.7 eV below the valence band maximum; however, the lowest 4f N-15d states are 2.2 eV below the conduction band for both ions. We found that a simple model accurately describes the binding energies of the 4f N, 4f N-15d, and 4f N+1 states. The model's success across the entire rare-earth series indicates that measurements on two different ions in a host are sufficient to predict the energies of all rare-earth ions in that host. This information provides new insight into electron transfer transitions, luminescence quenching, and valence stability. All of these results lead to a clearer picture for the host's effect on the rare-earth ion's electron binding energies and will motivate fundamental theoretical analysis and accelerate the development of new optical materials.