Quantum Engineering Laboratory
Our group studies quantum dynamics in nanoscale materials and devices using optics and electronics. We seek to better understand complex quantum-mechanical systems, with a goal of developing new technologies for communication, computation, and sensing based on quantum physics.










News
- Congratulations, Yung!Congratulations to Yung on defending their PhD thesis!
- Congratulations, Alex!Alex Breitweiser is awarded an IBM PhD Fellowship.
- Congratulations, Jordan!Incoming PhD student Jordan Gusdorff is awarded an NSF Graduate Research Fellowship.
- Congratulations, Abby!Abigail Poteshman is awarded the William E. Stephens Prize from the Penn. Dept. of Physics & Astronomy.
- Our paper on real-time control is selected as an Editor’s suggestion in Phys. Rev. Applied
Recent Publications
![]() | Shulevitz, Henry J; Huang, Tzu-Yung; Xu, Jun; Neuhaus, Steven; Patel, Raj N; Lee C. Bassett, Cherie Kagan R Template-Assisted Self Assembly of Fluorescent Nanodiamonds for Scalable Quantum Technologies Journal Article ACS Nano, 16 (2), pp. 1847–1856, 2022. @article{Shulevitz2021, title = {Template-Assisted Self Assembly of Fluorescent Nanodiamonds for Scalable Quantum Technologies}, author = {Henry J. Shulevitz and Tzu-Yung Huang and Jun Xu and Steven Neuhaus and Raj N. Patel and Lee C. Bassett, Cherie R. Kagan}, url = {https://arxiv.org/abs/2111.14921}, doi = {10.1021/acsnano.1c09839}, year = {2022}, date = {2022-01-13}, journal = {ACS Nano}, volume = {16}, number = {2}, pages = {1847–1856}, abstract = {Milled nanodiamonds containing nitrogen-vacancy (NV) centers provide an excellent platform for sensing applications as they are optically robust, have nanoscale quantum sensitivity, and form colloidal dispersions which enable bottom-up assembly techniques for device integration. However, variations in their size, shape, and surface chemistry limit the ability to position individual nanodiamonds and statistically study properties that affect their optical and quantum characteristics. Here, we present a scalable strategy to form ordered arrays of nanodiamonds using capillary-driven, template-assisted self assembly. This method enables the precise spatial arrangement of isolated nanodiamonds with diameters below 50 nm across millimeter-scale areas. Measurements of over 200 assembled nanodiamonds yield a statistical understanding of their structural, optical, and quantum properties. The NV centers' spin and charge properties are uncorrelated with nanodiamond size, but rather are consistent with heterogeneity in their nanoscale environment. This flexible assembly method, together with improved understanding of the material, will enable the integration of nanodiamonds into future quantum photonic and electronic devices.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Milled nanodiamonds containing nitrogen-vacancy (NV) centers provide an excellent platform for sensing applications as they are optically robust, have nanoscale quantum sensitivity, and form colloidal dispersions which enable bottom-up assembly techniques for device integration. However, variations in their size, shape, and surface chemistry limit the ability to position individual nanodiamonds and statistically study properties that affect their optical and quantum characteristics. Here, we present a scalable strategy to form ordered arrays of nanodiamonds using capillary-driven, template-assisted self assembly. This method enables the precise spatial arrangement of isolated nanodiamonds with diameters below 50 nm across millimeter-scale areas. Measurements of over 200 assembled nanodiamonds yield a statistical understanding of their structural, optical, and quantum properties. The NV centers' spin and charge properties are uncorrelated with nanodiamond size, but rather are consistent with heterogeneity in their nanoscale environment. This flexible assembly method, together with improved understanding of the material, will enable the integration of nanodiamonds into future quantum photonic and electronic devices. |
![]() | Narun, Leah R; Fishman, Rebecca E K; Shulevitz, Henry J; Patel, Raj N; Bassett, Lee C Efficient Analysis of Photoluminescence Images for the Classification of Single-Photon Emitters Journal Article Forthcoming Forthcoming. @article{Narun2021, title = {Efficient Analysis of Photoluminescence Images for the Classification of Single-Photon Emitters}, author = {Leah R. Narun and Rebecca E. K. Fishman and Henry J. Shulevitz and Raj N. Patel and Lee C. Bassett}, url = {https://arxiv.org/abs/2112.05654}, year = {2021}, date = {2021-12-31}, abstract = {Solid-state single-photon emitters (SPE) are a basis for emerging technologies such as quantum communication and quantum sensing. SPE based on fluorescent point defects are ubiquitous in semiconductors and insulators, and new systems with desirable properties for quantum information science may exist amongst the vast number of unexplored defects. However, the characterization of new SPE typically relies on time-consuming techniques for identifying point source emitters by eye in photoluminescence (PL) images. This manual strategy is a bottleneck for discovering new SPE, motivating a more efficient method for characterizing emitters in PL images. Here we present a quantitative method using image analysis and regression fitting to automatically identify Gaussian emitters in PL images and classify them according to their stability, shape, and intensity relative to the background. We demonstrate efficient emitter classification for SPEs in nanodiamond arrays and hexagonal boron nitride flakes. Adaptive criteria detect SPE in both samples despite variation in emitter intensity, stability, and background features. The detection criteria can be tuned for specific material systems and experimental setups to accommodate the diverse properties of SPE.}, keywords = {}, pubstate = {forthcoming}, tppubtype = {article} } Solid-state single-photon emitters (SPE) are a basis for emerging technologies such as quantum communication and quantum sensing. SPE based on fluorescent point defects are ubiquitous in semiconductors and insulators, and new systems with desirable properties for quantum information science may exist amongst the vast number of unexplored defects. However, the characterization of new SPE typically relies on time-consuming techniques for identifying point source emitters by eye in photoluminescence (PL) images. This manual strategy is a bottleneck for discovering new SPE, motivating a more efficient method for characterizing emitters in PL images. Here we present a quantitative method using image analysis and regression fitting to automatically identify Gaussian emitters in PL images and classify them according to their stability, shape, and intensity relative to the background. We demonstrate efficient emitter classification for SPEs in nanodiamond arrays and hexagonal boron nitride flakes. Adaptive criteria detect SPE in both samples despite variation in emitter intensity, stability, and background features. The detection criteria can be tuned for specific material systems and experimental setups to accommodate the diverse properties of SPE. |
![]() | Fishman, Rebecca E K; Patel, Raj N; Hopper, David A; Huang, Tzu-Yung; Bassett, Lee C Photon emission correlation spectroscopy as an analytical tool for quantum defects Journal Article Forthcoming Forthcoming. @article{Fishman2021, title = {Photon emission correlation spectroscopy as an analytical tool for quantum defects}, author = {Rebecca E. K. Fishman and Raj N. Patel and David A. Hopper and Tzu-Yung Huang and Lee C. Bassett}, url = {https://arxiv.org/abs/2111.01252}, year = {2021}, date = {2021-11-04}, abstract = {Photon emission correlation spectroscopy has a long history in the study of atoms, molecules, and, more recently, solid-state quantum defects. In solid-state systems, its most common use is as an indicator of single-photon emission, a key property for quantum technology. However, photon correlation data can provide a wealth of information about quantum emitters beyond their single-photon purity−information that can reveal details about an emitter's electronic structure and optical dynamics that are hidden by other spectroscopy techniques. We present a standardized framework for using photon emission correlation spectroscopy to study quantum emitters, including discussion of theory, data acquisition, analysis, and interpretation. We highlight nuances and best practices regarding the commonly used g(2)(τ=0)<0.5 test for single-photon emission. Finally, we illustrate how this experimental technique can be paired with optical dynamics simulations to formulate an electronic model for unknown quantum emitters, enabling the design of quantum control protocols and assessment of their suitability for quantum information science applications.}, keywords = {}, pubstate = {forthcoming}, tppubtype = {article} } Photon emission correlation spectroscopy has a long history in the study of atoms, molecules, and, more recently, solid-state quantum defects. In solid-state systems, its most common use is as an indicator of single-photon emission, a key property for quantum technology. However, photon correlation data can provide a wealth of information about quantum emitters beyond their single-photon purity−information that can reveal details about an emitter's electronic structure and optical dynamics that are hidden by other spectroscopy techniques. We present a standardized framework for using photon emission correlation spectroscopy to study quantum emitters, including discussion of theory, data acquisition, analysis, and interpretation. We highlight nuances and best practices regarding the commonly used g(2)(τ=0)<0.5 test for single-photon emission. Finally, we illustrate how this experimental technique can be paired with optical dynamics simulations to formulate an electronic model for unknown quantum emitters, enabling the design of quantum control protocols and assessment of their suitability for quantum information science applications. |
![]() | Kagan, Cherie R; Bassett, Lee C; Murray, Christopher B; Thompson, Sarah M Colloidal Quantum Dots as Platforms for Quantum Information Science Journal Article Chemical Reviews, 2020. @article{Kagan2020, title = {Colloidal Quantum Dots as Platforms for Quantum Information Science}, author = {Cherie R. Kagan and Lee C. Bassett and Christopher B. Murray and Sarah M. Thompson}, url = {https://pubs.acs.org/doi/10.1021/acs.chemrev.0c00831}, doi = {10.1021/acs.chemrev.0c00831}, year = {2020}, date = {2020-12-29}, journal = {Chemical Reviews}, abstract = {Colloidal quantum dots (QDs) are nanoscale semiconductor crystals with surface ligands that enable their dispersion in solvents. Quantum confinement effects facilitate wave function engineering to sculpt the spatial distribution of charge and spin states and thus the energy and dynamics of QD optical transitions. Colloidal QDs can be integrated in devices using solution-based assembly methods to position single QDs and to create ordered QD arrays. Here, we describe the synthesis, assembly, and photophysical properties of colloidal QDs that have captured scientific imagination and have been harnessed in optical applications. We focus especially on the current understanding of their quantum coherent effects and opportunities to exploit QDs as platforms for quantum information science. Freedom in QD design to isolate and control the quantum mechanical properties of charge, spin, and light presents various approaches to create systems with robust, addressable quantum states. We consider the attributes of QDs for optically addressable qubits in emerging quantum computation, sensing, simulation, and communication technologies, e.g., as robust sources of indistinguishable, single photons that can be integrated into photonic structures to amplify, direct, and tune their emission or as hosts for isolated, coherent spin states that can be coupled to light or to other spins in QD arrays.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Colloidal quantum dots (QDs) are nanoscale semiconductor crystals with surface ligands that enable their dispersion in solvents. Quantum confinement effects facilitate wave function engineering to sculpt the spatial distribution of charge and spin states and thus the energy and dynamics of QD optical transitions. Colloidal QDs can be integrated in devices using solution-based assembly methods to position single QDs and to create ordered QD arrays. Here, we describe the synthesis, assembly, and photophysical properties of colloidal QDs that have captured scientific imagination and have been harnessed in optical applications. We focus especially on the current understanding of their quantum coherent effects and opportunities to exploit QDs as platforms for quantum information science. Freedom in QD design to isolate and control the quantum mechanical properties of charge, spin, and light presents various approaches to create systems with robust, addressable quantum states. We consider the attributes of QDs for optically addressable qubits in emerging quantum computation, sensing, simulation, and communication technologies, e.g., as robust sources of indistinguishable, single photons that can be integrated into photonic structures to amplify, direct, and tune their emission or as hosts for isolated, coherent spin states that can be coupled to light or to other spins in QD arrays. |