Defect and coherent transient optical spectroscopy of rare-earth doped crystals

Jianying Zhou, G.Q. Wang, D.C. Dai +3 more

Zach J. Simmons

Matthew J. Sellars

Nathalie Kunkel, John G. Bartholomew, Laurent Binet +2 more

We present a case study on Eu 3+ -doped Y 2 O 3 transparent ceramics in which high-resolution laser spectroscopy is used as a material characterization tool. By comparing the results from coherent and incoherent optical spectroscopy with other characterization methods, we show that optical techniques can deliver supplementary information about the local environment of the activator ions in materials. Thus, high-resolution spectroscopy may be of interest for the investigation of a wider range of rare earth doped optical materials beyond materials studied for quantum information technology. The refinement of optical spectroscopy for the study of narrow optical transitions in rare earth ion single crystals has demonstrated that these techniques are extremely sensitive tools for probing the local environment of the rare earth ion. These techniques, such as photon echo experiments, have been important in developing materials for quantum information technology and spectral filtering applications. Here, we apply these techniques to transparent ceramic samples and compare the results with information gained from conventional material characterization techniques. Our present study demonstrates the high sensitivity of laser spectroscopic methods to microstructural strain and the presence of defects. In particular, the sensitivity is sufficient to detect small changes introduced by different thermal treatments in nominally equivalent materials. The results of our work show that it is possible to relate high-resolution optical measurements to defects and microstructural strain.

Leonardo V. S. França, Shaan Doshi, Haitao Zhang +1 more

Abstract Charge‐trapping defects in crystalline solids play important roles in applications ranging from microelectronics, optical storage, sensing and quantum technologies. On one hand, depleting trapped charges in the host matrix reduces charge noise and enhances coherence of solid‐state quantum emitters. On the other hand, stable charge traps can enable high‐density optical storage systems. Here we report all‐optical control of charge‐trapping defects via optical charge trapping (OCT) spectroscopy of a rare‐earth ion doped oxide (Y 2 O 3 ). Charge trapping is realized by low intensity optical excitation in the 200–375 nm range. Charge detrapping or depletion is carried out by optically stimulated luminescence (OSL) under 532 nm stimulation. Using a Pr‐doped Y 2 O 3 polycrystalline ceramic host matrix, we observe charging pathways via the inter‐band optical absorption of Y 2 O 3 and via the 4f‐5d transitions of Pr 3+ . We demonstrate effective control of the density of trapped charges within the Y 2 O 3 matrix at ambient environment. These results point to a viable method for controlling the local charge environment in rare‐earth doped crystals via all‐optical means, and pave the way for further development of efficient optical storage technologies with ultrahigh storage capacity, as well as for the localized control of quantum coherence in rare‐earth doped solids.

T. Kushida