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Nathan Youngblood

Assistant Professor
Personal Website Google Scholar Electrical and Computer Engineering

overview

Dr. Youngblood is an Assistant Professor in the Department of Electrical and Computer Engineering at the University of Pittsburgh. Prior to Pitt, he was a postdoctoral researcher at the University of Oxford where he developed phase-change optical systems and photonic architectures for non-von Neumann computing. Dr. Youngblood is a recipient of the NSF CAREER and AFOSR Young Investigator awards and leads the Youngblood Photonics Lab at Pitt, whose goal is to develop reconfigurable photonic materials, devices, and architectures which have potential to transform the field of artificial intelligence by minimizing computing latency and energy consumption. His work has been published in leading journals such as Nature, Nature Photonics, and Science Advances, and featured in popular news outlets such as The Times and the Daily Mail.

about

PhD, Electrical and Computer Engineering, University of Minnesota, 2012 - 2016

MSc, Electrical and Computer Engineering, University of Minnesota, 2012 - 2015

BS, Physics, Bethel University, 2007 - 2011

Gholipour, B., Youngblood, N., Wang, Q., Wu, P.C., Barclay, P., & Ou, J.Y. (2024). Reconfigurable photonic platforms: feature issue introduction. Optical Materials Express, 14(1), 236.Optica Publishing Group. doi: 10.1364/ome.510620.

Erickson, J.R., Nobile, N.A., Vaz, D., Vinod, G., Ocampo, C.A.R., Zhang, Y., Hu, J., Vitale, S.A., Xiong, F., & Youngblood, N. (2023). Comparing the thermal performance and endurance of resistive and PIN silicon microheaters for phase-change photonic applications. OPTICAL MATERIALS EXPRESS, 13(6), 1677-1688.Optica Publishing Group. doi: 10.1364/OME.488564.

Kari, S.R., Ocampo, C.A.R.A., Jiang, L., Meng, J., Peserico, N., Sorger, V.J.J., Hu, J., & Youngblood, N. (2023). Optical and Electrical Memories for Analog Optical Computing. IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS, 29(2), 1-12.Institute of Electrical and Electronics Engineers (IEEE). doi: 10.1109/JSTQE.2023.3239918.

Nobile, N.A., Erickson, J.R., Rios, C., Zhang, Y., Hu, J., Vitale, S.A., Xiong, F., & Youngblood, N. (2023). Time-Resolved Temperature Mapping Leveraging the Strong Thermo-Optic Effect in Phase-Change Materials. ACS PHOTONICS, 10(10), 3576-3585.American Chemical Society (ACS). doi: 10.1021/acsphotonics.3c00620.

Nobile, N.A., Lian, C., Sun, H., Huang, Y.S., Mills, B., Popescu, C.C., Callahan, D., Hu, J., Ocampo, C.A.R., & Youngblood, N. (2023). Nonvolatile Tuning of Bragg Structures Using Transparent Phase-Change Materials. Optical Materials Express, 13(10), 2700.Optica Publishing Group. doi: 10.1364/ome.498931.

Shah, V., & Youngblood, N. (2023). AnalogVNN: A fully modular framework for modeling and optimizing photonic neural networks. APL Mach. Learn. 1 June 2023; 1 (2): 026116, 1(2).AIP Publishing. doi: 10.1063/5.0134156.

Youngblood, N. (2023). Coherent Photonic Crossbar Arrays for Large-Scale Matrix-Matrix Multiplication. IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS, 29(2), 1-11.Institute of Electrical and Electronics Engineers (IEEE). doi: 10.1109/JSTQE.2022.3171167.

Youngblood, N., Rios Ocampo, C.A., Pernice, W.H.P., & Bhaskaran, H. (2023). Integrated optical memristors. NATURE PHOTONICS, 17(7), 561-572.Springer Science and Business Media LLC. doi: 10.1038/s41566-023-01217-w.

Zhou, W., Dong, B., Farmakidis, N., Li, X., Youngblood, N., Huang, K., He, Y., David Wright, C., Pernice, W.H.P., & Bhaskaran, H. (2023). In-memory photonic dot-product engine with electrically programmable weight banks. NATURE COMMUNICATIONS, 14(1), 2887.Springer Science and Business Media LLC. doi: 10.1038/s41467-023-38473-x.

Erickson, J.R., Shah, V., Wan, Q., Youngblood, N., & Xiong, F. (2022). Designing fast and efficient electrically driven phase change photonics using foundry compatible waveguide-integrated microheaters. OPTICS EXPRESS, 30(8), 13673-13689.Optica Publishing Group. doi: 10.1364/OE.446984.

Farmakidis, N., Youngblood, N., Lee, J.S., Feldmann, J., Lodi, A., Li, X., Aggarwal, S., Zhou, W., Bogani, L., Pernice, W.H., Wright, C.D., & Bhaskaran, H. (2022). Electronically Reconfigurable Photonic Switches Incorporating Plasmonic Structures and Phase Change Materials. ADVANCED SCIENCE, 9(20), e2200383.Wiley. doi: 10.1002/advs.202200383.

Lian, C., Vagionas, C., Alexoudi, T., Pleros, N., Youngblood, N., & Rios, C. (2022). Photonic (computational) memories: tunable nanophotonics for data storage and computing. NANOPHOTONICS, 11(17), 3823-3854.Walter de Gruyter GmbH. doi: 10.1515/nanoph-2022-0089.

Tan, J.Y.S., Cheng, Z., Feldmann, J., Li, X., Youngblood, N., Ali, U.E., Wright, C.D., Pernice, W.H.P., & Bhaskaran, H. (2022). Monadic Pavlovian associative learning in a backpropagation-free photonic network. OPTICA, 9(7), 792-802.Optica Publishing Group. doi: 10.1364/OPTICA.455864.

Youngblood, N., Talagrand, C., Porter, B.F., Galante, C.G., Kneepkens, S., Triggs, G., Sarwat, S.G., Yarmolich, D., Bonilla, R.S., Hosseini, P., Taylor, R.A., & Bhaskaran, H. (2022). Reconfigurable Low-Emissivity Optical Coating Using Ultrathin Phase Change Materials. ACS PHOTONICS, 9(1), 90-100.American Chemical Society (ACS). doi: 10.1021/acsphotonics.1c01128.

Farmakidis, N., Swett, J.L., Youngblood, N., Li, X., Evangeli, C., Aggarwal, S., Mol, J.A., & Bhaskaran, H. (2021). Exploiting rotational asymmetry for sub-50 nm mechanical nanocalligraphy. MICROSYSTEMS & NANOENGINEERING, 7(1), 84.Springer Science and Business Media LLC. doi: 10.1038/s41378-021-00300-y.

Feldmann, J., Youngblood, N., Karpov, M., Gehring, H., Li, X., Stappers, M., Le Gallo, M., Fu, X., Lukashchuk, A., Raja, A.S., Liu, J., Wright, C.D., Sebastian, A., Kippenberg, T.J., Pernice, W.H.P., & Bhaskaran, H. (2021). Parallel convolutional processing using an integrated photonic tensor core. NATURE, 589(7840), 52-+.Springer Science and Business Media LLC. doi: 10.1038/s41586-020-03070-1.

Feldmann, J., Youngblood, N., Karpov, M., Gehring, H., Li, X., Stappers, M., Le Gallo, M., Fu, X., Lukashchuk, A., Raja, A.S., Liu, J., Wright, C.D., Sebastian, A., Kippenberg, T.J., Pernice, W.H.P., & Bhaskaran, H. (2021). Parallel convolutional processing using an integrated photonic tensor core (vol 589, pg 52, 2021). NATURE, 591(7849), E13.Springer Science and Business Media LLC. doi: 10.1038/s41586-021-03216-9.

Ma, X., Youngblood, N., Liu, X., Cheng, Y., Cunha, P., Kudtarkar, K., Wang, X., & Lan, S. (2021). Engineering photonic environments for two-dimensional materials. NANOPHOTONICS, 10(3), 1031-1058.Walter de Gruyter GmbH. doi: 10.1515/nanoph-2020-0524.

Feldmann, J., Youngblood, N., Li, X., Wright, C.D., Bhaskaran, H., & Pernice, W.H.P. (2020). Integrated 256 Cell Photonic Phase-Change Memory With 512-Bit Capacity. IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS, 26(2), 1-7.Institute of Electrical and Electronics Engineers (IEEE). doi: 10.1109/JSTQE.2019.2956871.

He, Q., Youngblood, N., Cheng, Z., Miao, X., & Bhaskaran, H. (2020). Dynamically tunable transmissive color filters using ultra-thin phase change materials. OPTICS EXPRESS, 28(26), 39841-39849.Optica Publishing Group. doi: 10.1364/OE.411874.

Li, X., Youngblood, N., Cheng, Z., Carrillo, S.G.C., Gemo, E., Pernice, W.H.P., Wright, C.D., & Bhaskaran, H. (2020). Experimental investigation of silicon and silicon nitride platforms for phase-change photonic in-memory computing. OPTICA, 7(3), 218-225.Optica Publishing Group. doi: 10.1364/OPTICA.379228.

Li, X., Youngblood, N., Cheng, Z., Carrillo, S.G.C., Gemo, E., Pernice, W.H.P., Wright, C.D., & Bhaskaran, H. (2020). Experimental investigation of silicon and silicon nitride platforms for phase-change photonic in-memory computing: erratum. Optica, 7(12), 1804.Optica Publishing Group. doi: 10.1364/optica.414370.

Shen, Y., Yang, X., Naidoo, D., Fu, X., & Forbes, A. (2020). Structured ray-wave vector vortex beams in multiple degrees of freedom from a laser: erratum. Optica, 7(12), 1705.Optica Publishing Group. doi: 10.1364/optica.414397.

Carrillo, S.G.C., Gemo, E., Li, X., Youngblood, N., Katumba, A., Bienstman, P., Pernice, W., Bhaskaran, H., & Wright, C.D. (2019). Behavioral modeling of integrated phase-change photonic devices for neuromorphic computing applications. APL MATERIALS, 7(9).AIP Publishing. doi: 10.1063/1.5111840.

Farmakidis, N., Youngblood, N., Li, X., Tan, J., Swett, J.L., Cheng, Z., Wright, C.D., Pernice, W.H.P., & Bhaskaran, H. (2019). Plasmonic nanogap enhanced phase-change devices with dual electrical-optical functionality. SCIENCE ADVANCES, 5(11), eaaw2687.American Association for the Advancement of Science (AAAS). doi: 10.1126/sciadv.aaw2687.

Feldmann, J., Youngblood, N., Wright, C.D., Bhaskaran, H., & Pernice, W.H.P. (2019). All-optical spiking neurosynaptic networks with self-learning capabilities. NATURE, 569(7755), 208-+.Springer Science and Business Media LLC. doi: 10.1038/s41586-019-1157-8.

Gemo, E., Carrillo, S.G.C., DeGalarreta, C.R., Baldycheva, A., Hayat, H., Youngblood, N., Bhaskaran, H., Pernice, W.H.P., & Wright, C.D. (2019). Plasmonically-enhanced all-optical integrated phase-change memory. OPTICS EXPRESS, 27(17), 24724-+.The Optical Society. doi: 10.1364/OE.27.024724.

Li, X., Youngblood, N., Rios, C., Cheng, Z., Wright, C.D., Pernice, W.H.P., & Bhaskaran, H. (2019). Fast and reliable storage using a 5 bit, nonvolatile photonic memory cell. OPTICA, 6(1), 1-6.The Optical Society. doi: 10.1364/OPTICA.6.000001.

Rios, C., Youngblood, N., Cheng, Z., Le Gallo, M., Pernice, W.H.P., Wright, C.D., Sebastian, A., & Bhaskaran, H. (2019). In-memory computing on a photonic platform. SCIENCE ADVANCES, 5(2), eaau5759.American Association for the Advancement of Science (AAAS). doi: 10.1126/sciadv.aau5759.

Sarwat, S.G., Cheng, Z., Youngblood, N., Alias, M.S., Sinha, S., Warner, J., & Bhaskaran, H. (2019). Strong Opto-Structural Coupling in Low Dimensional GeSe3 Films. NANO LETTERS, 19(10), 7377-7384.American Chemical Society (ACS). doi: 10.1021/acs.nanolett.9b03039.

Youngblood, N., Rios, C., Gemo, E., Feldmann, J., Cheng, Z., Baldycheva, A., Pernice, W.H.P., Wright, C.D., & Bhaskaran, H. (2019). Tunable Volatility of Ge2Sb2Te5 in Integrated Photonics. ADVANCED FUNCTIONAL MATERIALS, 29(11).Wiley. doi: 10.1002/adfm.201807571.

Cheng, Z., Rios, C., Youngblood, N., Wright, C.D., Pernice, W.H.P., & Bhaskaran, H. (2018). Device-Level Photonic Memories and Logic Applications Using Phase-Change Materials. ADVANCED MATERIALS, 30(32), e1802435.Wiley. doi: 10.1002/adma.201802435.

Rios, C., Stegmaier, M., Cheng, Z., Youngblood, N., Wright, C.D., Pernice, W.H.P., & Bhaskaran, H. (2018). Controlled switching of phase-change materials by evanescent-field coupling in integrated photonics. OPTICAL MATERIALS EXPRESS, 8(9), 2455-2470.The Optical Society. doi: 10.1364/OME.8.002455.

Sarwat, S.G., Youngblood, N., Au, Y.Y., Mol, J.A., Wright, C.D., & Bhaskaran, H. (2018). Engineering Interface-Dependent Photoconductivity in Ge2Sb2Te5 Nanoscale Devices. ACS APPLIED MATERIALS & INTERFACES, 10(51), 44906-44914.American Chemical Society (ACS). doi: 10.1021/acsami.8b17602.

Chen, C., Youngblood, N., Peng, R., Yoo, D., Mohr, D.A., Johnson, T.W., Oh, S.H., & Li, M. (2017). Three-Dimensional Integration of Black Phosphorus Photodetector with Silicon Photonics and Nanoplasmonics. NANO LETTERS, 17(2), 985-991.American Chemical Society (ACS). doi: 10.1021/acs.nanolett.6b04332.

Peng, R., Khaliji, K., Youngblood, N., Grassi, R., Low, T., & Li, M. (2017). Midinfrared Electro-optic Modulation in Few-Layer Black Phosphorus. NANO LETTERS, 17(10), 6315-6320.American Chemical Society (ACS). doi: 10.1021/acs.nanolett.7b03050.

Xu, M., Gu, Y., Peng, R., Youngblood, N., & Li, M. (2017). Black phosphorus mid-infrared photodetectors. APPLIED PHYSICS B-LASERS AND OPTICS, 123(4).Springer Science and Business Media LLC. doi: 10.1007/s00340-017-6698-7.

Youngblood, N., & Li, M. (2017). Ultrafast photocurrent measurements of a black phosphorus photodetector. APPLIED PHYSICS LETTERS, 110(5).AIP Publishing. doi: 10.1063/1.4975360.

Youngblood, N., & Li, M. (2017). Integration of 2D materials on a silicon photonics platform for optoelectronics applications. NANOPHOTONICS, 6(6), 1205-1218.Walter de Gruyter GmbH. doi: 10.1515/nanoph-2016-0155.

Youngblood, N., Peng, R., Nemilentsau, A., Low, T., & Li, M. (2017). Layer-Tunable Third-Harmonic Generation in Multilayer Black Phosphorus. ACS PHOTONICS, 4(1), 8-14.American Chemical Society (ACS). doi: 10.1021/acsphotonics.6b00639.

Lee, S.C., Youngblood, N., Jiang, Y.B., Peterson, E.J., Stark, C.J.M., Detchprohm, T., Wetzel, C., & Brueck, S.R.J. (2015). Incorporation of indium on cubic GaN epitaxially induced on a nanofaceted Si(001) substrate by phase transition. APPLIED PHYSICS LETTERS, 107(23).AIP Publishing. doi: 10.1063/1.4936772.

Youngblood, N., Chen, C., Koester, S.J., & Li, M. (2015). Waveguide-integrated black phosphorus photodetector with high responsivity and low dark current. NATURE PHOTONICS, 9(4), 247-252.Springer Science and Business Media LLC. doi: 10.1038/NPHOTON.2015.23.

Youngblood, N., Anugrah, Y., Ma, R., Koester, S.J., & Li, M. (2014). Multifunctional Graphene Optical Modulator and Photodetector Integrated on Silicon Waveguides. NANO LETTERS, 14(5), 2741-2746.American Chemical Society (ACS). doi: 10.1021/nl500712u.

Li, X., Youngblood, N., Wright, C.D., Pernice, W.H.P., & Bhaskaran, H. Non-volatile silicon photonic memory with more than 4-bit per cell capability.

Shah, V., & Youngblood, N. Leveraging Continuously Differentiable Activation Functions for Learning in Quantized Noisy Environments.

Youngblood, N., Talagrand, C., Porter, B., Galante, C.G., Kneepkens, S., Sarwat, S.G., Yarmolich, D., Bonilla, R.S., Hosseini, P., Taylor, R., & Bhaskaran, H. Broadly-tunable smart glazing using an ultra-thin phase-change material.

Gemo, E., García-Cuevas Carrillo, S., Faneca, J., Ruíz de Galarreta, C., Hayat, H., Youngblood, N., Baldycheva, A., Pernice, W.H.P., Bhaskaran, H., & Wright, C.D. (2020). Sub-wavelength plasmonic-enhanced phase-change memory. In Photonic and Phononic Properties of Engineered Nanostructures X, 11289.SPIE. doi: 10.1117/12.2546031.

Li, X., Youngblood, N., Zhou, W., Feldmann, J., Swett, J., Aggarwal, S., Sebastian, A., Wright, C.D., Pernice, W., & Bhaskaran, H. (2020). On-chip Phase Change Optical Matrix Multiplication Core. In 2020 IEEE International Electron Devices Meeting (IEDM), 2020-December, (pp. 7.5.1-7.5.4).IEEE. doi: 10.1109/iedm13553.2020.9372052.

Youngblood, N., Farmakidis, N., Li, X., & Bhaskaran, H. (2020). Nanoscale Optoelectronic Memory with Nonvolatile Phase-Change Photonics. In Conference Proceedings - Lasers and Electro-Optics Society Annual Meeting-LEOS, 2020-May.

Zokaee, F., Lou, Q., Youngblood, N., Liu, W., Xie, Y., & Jiang, L. (2020). LightBulb: A Photonic-Nonvolatile-Memory-based Accelerator for Binarized Convolutional Neural Networks. In 2020 Design, Automation & Test in Europe Conference & Exhibition (DATE), (pp. 1438-1443).IEEE. doi: 10.23919/date48585.2020.9116494.

David Wright, C., Bhaskaran, H., Wolfram, H.P.P., Carrillo, S.G.C., Gemo, E., Baldycheva, A., Cheng, Z., Li, X., Rios, C., Youngblood, N., Feldmann, J., Gruhler, N., & Stegmaier, M. (2019). Integrated Phase-change Photonics: A strategy for merging communication and computing. In Optics InfoBase Conference Papers, Part F160-OFC 2019.

Rios, C., Youngblood, N., Cheng, Z., Gallo, M.L., Pernice, W.H.P., Wright, C., Sebastian, A., & Bhaskaran, H. (2019). All-Photonic in-Memory Computing Based on Phase-Change Materials. In 2019 Conference on Lasers and Electro-Optics, CLEO 2019 - Proceedings. doi: 10.23919/CLEO.2019.8749826.

Ríos, C., Youngblood, N., Cheng, Z., Le Gallo, M., Pernice, W.H.P., Wright, C.D., Sebastian, A., & Bhaskaran, H. (2019). All-photonic in-memory computing based on phase-change materials. In Conference on Lasers and Electro-Optics, Part F129-CLEO_SI 2019.OSA. doi: 10.1364/cleo_si.2019.sm2j.2.

Wright, C.D., Bhaskaran, H., Pernice, W.H.P., Carrillo, S.G.C., Gemo, E., Baldycheva, A., Cheng, Z., Li, X., Rios, C., Youngblood, N., Feldmann, J., Gruhler, N., & Stegmaier, M. (2019). Integrated Phase-change Photonics: A Strategy for Merging Communication and Computing. In Optical Fiber Communication Conference (OFC) 2019.OSA. doi: 10.1364/ofc.2019.m1d.3.

Bhaskaran, H., Cheng, Z., Rios, C.A., Youngblood, N., Wright, C.D., & Pernice, W.H. (2017). On-chip phase-change photonic memory and computing. In Active Photonic Platforms IX, 10345.SPIE. doi: 10.1117/12.2272127.

Chen, C., Yoo, D., Youngblood, N., Oh, S.H., & Li, M. (2017). Mid-Infrared Plasmonic Coaxial Nanorings for Surface Enhanced Infrared Absorption (SEIRA) Spectroscopy. In Conference on Lasers and Electro-Optics, 2017-January, (pp. 1-2).OSA. doi: 10.1364/cleo_at.2017.jth2a.36.

Peng, R., Youngblood, N., & Li, M. (2017). Mid-Infrared Electro-Optic Modulation in Black Phosphorus. In Conference on Lasers and Electro-Optics, 2017-January, (pp. 1-2).OSA. doi: 10.1364/cleo_qels.2017.fw4h.7.

Chen, C., Youngblood, N., Mohr, D., Yoo, D., Johnson, T., Peng, R., Oh, S.H., & Li, M. (2016). Black Phosphorus Photodetector on Silicon Photonic and Plasmonic Hybrid Platform. In Conference on Lasers and Electro-Optics.OSA. doi: 10.1364/cleo_si.2016.sm4e.6.

Youngblood, N., & Li, M. (2016). Ultrafast Photocurrent Spectroscopy in a Black Phosphorus Van der Waals Heterostructure. In Conference on Lasers and Electro-Optics.OSA. doi: 10.1364/cleo_si.2016.stu1r.4.

Youngblood, N., Peng, R., Nemilentsau, A., Low, T., & Li, M. (2016). Thickness dependent third-harmonic generation in few-layer black phosphorus. In Conference on Lasers and Electro-Optics.OSA. doi: 10.1364/cleo_at.2016.jth4c.9.

Chen, C., Youngblood, N., & Li, M. (2015). Study of black phosphorus anisotropy on silicon photonic waveguide. In 2015 Optoelectronics Global Conference (OGC).IEEE. doi: 10.1109/ogc.2015.7336864.

Youngblood, N., Chen, C., Koester, S.J., & Li, M. (2015). A Black Phosphorus FET Integrated on a Silicon Waveguide for High Speed, Low Dark Current Photodetection. In CLEO: 2015, 2015-August.OSA. doi: 10.1364/cleo_si.2015.sm3g.3.

Youngblood, N., Chen, C., Koester, S.J., & Li, M. (2015). A black phosphorus FET integrated on a silicon waveguide for high speed, low dark current photodetection. In CLEO: Science and Innovations, CLEO-SI 2015, (p. 2267). doi: 10.1364/CLEO_SI.2015.SM3G.3.

Youngblood, N., Anugrah, Y., Ma, R., Koester, S., & Li, M. (2014). Simultaneous optical modulation and detection using graphene integrated on a silicon waveguide. In CLEO: 2014, 2014-January.OSA. doi: 10.1364/cleo_si.2014.sth1m.3.

Youngblood, N., Anugrah, Y., Ma, R., Koester, S.J., & Li, M. (2014). Simultaneous optical modulation and detection using graphene integrated on a silicon waveguide. In Optics InfoBase Conference Papers.

Research interests

2D materials and devices
In-memory computing
Machine learning
Phase-change photonics
Silicon photonics