Faculty Directory

Carlos A. Rios Ocampo joined the Department of Materials Science and Engineering and IREAP as an assistant professor in August 2021 after completing his postdoc at MIT with Prof. JJ Hu. He received his Ph.D. in Materials Science from the University of Oxford in 2017 under Prof. Harish Bhaskaran's supervision, his M.S. degree in optics and photonics from Karlsruhe Institute of Technology, and his B.S. in physics from the University of Antioquia, Colombia in 2010.

Dr. Rios Ocampo is an expert in experimental and computational optics and photonics, demonstrated over 13 years of research using both integrated and free-space optical setups, which led to the creation of the world’s first light-based memory chip able to store data indefinitely and to carry in-memory computations, potentially changing the fundamentals of computing as we know them.

His current research interests include photonic and phase-change materials; nanoscale light-matter interactions, photonic integrated circuits and photonic (neuromorphic) computing.

In his spare time, Dr. Rios Ocampo enjoys spending time with friends and family; connecting with nature via hiking, camping, punting and other sports, including karate. A Colombian native, he has represented both Colombia and England on their national karate teams.

• Photonic materials
• Phase-change materials
• Nanoscale light-matter interactions
• Photonic integrated circuits
• Photonic (neuromorphic) computing

Spring 2025: ENMA481/ENMA681  Introduction to Electronic and Optical Materials/ Advanced Electronic and Optical Materials

Fall 2024: ENMA300 Introduction to Materials Engineering 

Spring 2024: ENMA300 Introduction to Materials Engineering 

Fall 2023: ENMA300 Introduction to Materials Engineering 

Spring 2023: ENMA300 Introduction to Materials Engineering 

Spring 2022: ENMA481/ENMA681  Introduction to Electronic and Optical Materials/ Advanced Electronic and Optical Materials

Please visit Carlos's Google scholar for an up to date list:

1. Y-S. Huang, C-Y Lee, I. Takeuchi, C.A. Rios Ocampo. “Optical Phase Change Materials.” Accepted. Annual Reviews of Materials Research, 2024.
2. [OA] H. Sun, et al. “Microheater hotspot engineering for reliable multi-level switching in foundry-processed phase change silicon photonics,” preprint:arXiv:2407.00059, 2024.
3. [OA] A. Chen, A.Leff, Z. Li, C.A. Rios Ocampo, J. Boltersdorf, and T. Woehl. “Visualizing Plasmonic Hot Carrier-Mediated Metal Deposition and Nanoparticle Reshaping with Liquid Phase Transmission Electron Microscopy” preprint: ChemRxiv; doi:10.26434/chemrxiv-2024-06bv8, 2024. Accepted in Matter.
4. [OA] S. R.Kari, M.Tamura, Z. Guo, Y-S. Huang, H. Sun, C. Lian, N. Nobile, J. Erickson, M. Moridsadat, C. A. Rios Ocampo, B. Shastri, N. Youngblood. “High-Speed Multifunctional Photonic Memory on a Foundry-Processed Photonic Platform.” preprint:ArXiv:2409.13954, 2024. Accepted in Optica.
5. G. Yang, et al. “SOPHIE: A Scalable Recurrent Ising Machine Using Optically Addressed Phase Change Memory,” accepted at MICRON 2024.
6. [OA] CC Popescu, K Aryana, P Garud, KP Dao, S Vitale, V Liberman, HB Bae, T.-W. Lee, M. Kang, K.A. Richardson, C.A. Ríos Ocampo, Y. Zhang, T. Gu, J. Hu, H-J. Kim. “Unravelling and circumventing failure mechanisms in chalcogeginde optical phase change materilas,” preprint: arXiv:2409.12313, 2024. Accepted in Advanced Optical Materials.
7. [OA] C. Wu, Z. Jiao, H. Deng, Y-S. Huang, H. Yu, I. Takeuchi, C.A. Rios Ocampo, M. Li. “Reconfigurable inverse designed phase-change photonics” arXiv:2403.05649, 2024. Under review in APL Photonics.
8. [OA] N. Acharjeen, et al. “GeSbSeTe on n=1 ITO: monolithic plaform for photonics with mode symmetrization and post-fabrication tuning,” J. Opt. Soc. Am. B 41, D81-D87 (2024)
9. [OA] CC Popescu, K Aryana, P Garud, KP Dao, S Vitale, V Liberman, HB Bae, T.-W. Lee, M. Kang, K.A. Richardson, C.A. Ríos Ocampo, Y. Zhang, T. Gu, J. Hu, H-J. Kim. “Electrically reconfigurable phase-change transmissive metasurface,” Advanced  Materials, 36, 2400627, 2024.
10. [OA] C Wu, H Deng, YS Huang, H Yu, I Takeuchi, CA Ríos Ocampo, M Li. “Freeform Direct-write and Rewritable Photonic Integrated Circuits in Phase-Change Thin Films” Science Advances 10, eadk1361, 2024.
11. [OA] C-Y Lee, C. Lian, Y-S. Huang, H. Sun, N. Acharjee, I. Takeuchi, C. Rios Ocampo. “Glassy-Crystalline Spatial and Temporal Distributions in Chalcogenide Phase Change Materials for Optical Modulation.” Journal of the American Society of Ceramics (JACerS) 107(3). 2023
    1. Finalist of the 2nd Century Trailblazer award for young researchers.
12. [OA] C.C. Popescu, K.P Dao, L. Ranno, B. Mills, L. Martin, Y. Zhang, D.B. Neltner, T. Gu, J. Hu, K. Aryana, W.M. Humphreys, … C.A. Rios Ocampo. “An Open-Source Multi-functional Testing Platform for Optical Phase Change Materials”. In press Small Science, 2023. (ArXiv preprint arXiv:2307.06216.)
13. G. Yang, C. Demirkiran, Z.E. Kizilates, C.A. Rios Ocampo, A. K. Coskun, and A. Joshi. “Processing-in-Memory Using Optically-Addressed Phase Change Memory.” 2023 IEEE/ACM International Symposium on Low Power Electronics and Design (ISLPED), 2023. doi: 10.1109/ISLPED58423.2023.10244409.
14. [OA] Z. Zhang, S. El-Henawy, C.A. Rios Ocampo, and D. Bonning. “Inference of Process Variations in Silicon Photonics from Characterization Measurements.” Optics Express 31 (14), 23651-23661, 2023
15. N. Youngblood, C.A. Rios Ocampo, W. Pernice, H. Bhaskaran. “Integrated Optical Memristors.” Nature Photonics, 2023. [link]
16. [OA] A. Nobile et al. “Time-resolved temperature mapping leveraging the strong thermo-optic effect in phase-change devices”. ArXiv preprint arXiv:2210.08142, 2022. [link]
17. [OA] R. Erickson, et al. “Comparing the thermal performance and endurance of resistive and PIN silicon microheaters for phase-change photonic applications.” Optical Materials Express 13(6), 2023. [link]
18. [OA] Y-S. Huang, C-Y Lee, …., C.  Ríos. “Tunable Structural Transmissive Color in Fano-Resonant Optical Coatings Employing Phase-Change Materials”. Materials Today Advances. 18, 100364, 2023 (Preprint: arXiv:2302.03207). [link]
19. R. Kari, C.A. Rios Ocampo, et al. “Optical and Electrical Memories for Analog Optical Computing”. IEEE Journal of Selected Topics in Quantum Electronics, 29 (2), 2023. [link]
20. Chen et al. “Programmable Integrated Photonics via Phase-Change Materials”. Optics & Photonics News 33, 2022. [link]
21. Ríos, L. Zhou, AKU Michel, A. Majumdar, J. Hu. “Phase Change Materials for Optics and Photonics: feature issue introduction.” Optical Materials Express 12 (11), 4284-4286, 2022.
22. [OA] Ríos et al. “Ultra-compact nonvolatile photonics based on electrically reprogrammable transparent phase change materials.” PhotoniX 3,26, 2022. [ArXiv.pdf] [link]
23. [OA] Vitale, S.A., Miller, P., Robinson, P., Roberts, C., Liberman, V., Du, Q., Zhang, Y., Popescu, C., Shalaginov, M.Y., Kang, M., Richardson, K.A., Gu, T., Ríos, C., Hu, J., “Phase Transformation and Switching Behavior of Magnetron Plasma Sputtered Ge₂Sb₂Se₄Te”. Adv. Photonics Res. 2200202, 2022. link
24. Z. Fang, R. Chen, J. Zheng, A. I. Khan, K. M. Neilson, S. J. Geiger,  M.G. Moebius, A. Saxena, M.E. Chen, C. Ríos, J. Hu, E. Pop, A. Majumdar. “Ultra-low-energy programmable non-volatile silicon photonics based on phase-change materials with graphene heaters”. Nature Nanotechnology, 17, 842–848, 2022 [link]
25. [OA] C. Lian, C. Vagionas, T. Alexoudi, N. Pleros, N. Youngblood, C. Ríos. “Photonic (computational) memories: tunable nanophotonics for data storage and computing.” Nanophotonics, 11 (17), 3823-3854, 2022.  link
26. [OA] E. Dolgopolova, D. Li, J. Watt, C. Ríos, et al. “Spinel Fe3O4 Nanocrystals with Size-Tunable Plasmonic Properties Afford Strong Enhancement of Emission at Telecom Wavelengths”. Nanoscale Horizons, 7, 267-275, 2022. [.pdf]
27. [OA] K. Aryana, Y. Zhang, J. A. Tomko, M. Hoque, E.R. Hoglund, D. H. Olson, J. Nag, J.C. Read, C. Ríos, J. Hu & P.E. Hopkins “Suppressed electronic contribution in thermal conductivity of Ge2Sb2Se4Te.” Nature Communications 12, 7187, 2021. [.pdf]

    • Prior to UMD:

28. Y. Zhang, Q. Zhang, C. Rios, et al. “Transient tap couplers for wafer-level photonic testing based on optical phase change materials.” ACS Photonics, ASAP article, 2021.
29. Y. Zhang, C. Ríos, M.Y. Shalaginov, M. Li, A. Majumdar, T. Gu, J. Hu. “Myths and truths about optical phase change materials: A perspective.” Applied Physics Letters 118(21), 210501, 2021.
30. [OA] Y. Zhang et al. “Electrically reconfigurable nonvolatile metasurface using low-loss optical phase change material’ Nat. Nanotechnology 16 (6), 661-666, 2021.
    • OPN Highlight in research 2021.
    • Nature Nanotechnology Nes & Views: Tunable phase-change metasurfaces
31. C. M. Schwarz, S. M. Kuebler, C. Rivero-Baleine, B. Triplett, M. Kang, Q. Altemose, C. Blanco, K. A. Richardson, Q. Du, S. Deckoff-Jones, J. Hu, Y. Zhang, Y. Pan, C. Ríos. “Structurally and morphologically engineered chalcogenide materials for optical and photonic devices” J. Opt. Microsystems 1(1), 2021.
32. [OA] C. Ríos, Y. Zhang, M. Shalaginov, S. Deckoff-Jones, H. Wang, S. An, H. Zhang, M. Kang, K. A. Richardson, C. Roberts, J. B Chou, V. Liberman, S. Vitale, J. Kong, T. Gu, J. Hu. “Multi-level electro-thermal switching of optical phase-change materials using graphene”. Adv. Photonics Research. 202000034. 2021
33. [OA] M. Shalaginov et al. “Reconfigurable all-dielectric metalens with diffraction-limited performance.”  Nat. Communications 12(1). 2021.
34. [OA] M. Y. Shalaginovr, S.D. Campbel, S. An, Y. Zhang, C. Ríos, et al. “Design for quality: reconfigurable flat optics based on active metasurfaces” Nanophotonics 9(11), 3505-3534, 2020.
35. [OA] C. Ríos, N. Youngblood, Z. Cheng, M. Le Gallo, W.H.P. Pernice, C.D. Wright, A. Sebastian & H. Bhaskaran. “In-memory computing on a photonic platform”. Science Advances, 5(2), eaau5759, 2019.      
    • Nature Electronics Research Highlight: Photonic devices compute in memory. Nat. Electronics 2, p. 91, 2019.
36. [OA} Y. Zhang, et al. “Broadband Transparent Optical Phase Change Materials for High-Performance Nonvolatile Photonics”. Nat. Communications 10 (1), 1-9, 2019.
37. [OA] S. García-Cuevas, L. Trimby, Y-Y. Au, V.K. Nagreddy, P. Hosseini, G. Rodriguez-Hernandez, C. Ríos, H.Bhaskaran & C.D. Wright. “A Nonvolatile Phase-Change Metamaterial Color Display”. Adv. Opt. Materials, p. 1801782, 2019.
38. [OA] N. Youngblood, C. Ríos, E. Gemo, J. Feldmann, Z. Cheng, A. Baldycheva, W.H.P. Pernice, C. D. Wright & H. Bhaskaran. “Tunable volatility of Ge2Sb2Te5 in integrated photonics”. Adv. Functional Materials, p.1807571, 2019.
39. [OA] X. Li, N. Youngblood, C. Ríos, Z. Cheng, W.H.P. Pernice, C.D. Wright & H. Bhaskaran. “Fast and reliable storage using a 5-bit, non-volatile photonic memory cell”. Optica, Vol. 6(1), 1-6, 2019.
40. J. von Keitz, J. Feldmann, N. Gruhler, C. Ríos, C. David Wright, Harish Bhaskaran & Wolfram Pernice. “Reconfigurable nanophotonic cavities with non-volatile response “. ACS Photonics, Vol. 5 (11), 4644-4649, 2018.
41. [OA] C. Ríos, M. Stegmaier, Z. Cheng, N. Youngblood, C.D. Wright, W.H.P. Pernice & H. Bhaskaran. “Controlled switching of phase-change materials by evanescent-field coupling in integrated photonics [Invited]” Opt. Mat. Express 8(9), 2018.
42. [OA] Z. Cheng, C. Ríos, N. Youngblood, C.D. Wright, W.H.P. Pernice & H. Bhaskaran. “Device‐Level Photonic Memories and Logic Applications Using Phase‐Change Materials”. Advanced Materials, 30(32), 1802435, 2018.
43. [OA] Z. Cheng, C. Ríos, W.H.P. Pernice, C.D. Wright, A. Sebastian & H. Bhaskaran. “On-chip photonic synapse”. Science Advances, Vol. 3 (9), e1700160, 2017.
44. [OA] J. Feldman, M. Stegmaier, N. Gruhler, C. Ríos, H. Bhaskaran, CD. Wright, WHP Pernice. “Calculating with light using a chip-scale all-optical abacus” Nature Communications, Vol 8 (1), 1256, 2017.
45. [OA] M. Stegmaier, C. Ríos, H, Bhaskaran, CD. Wright, WHP Pernice. “Non-volatile All-Optical 1×2 Switch for Chipscale Photonic Networks”. Adv. Optical Materials, Vol. 5(1), 1600346, 2017.
46. [OA] G. Rodriguez‐Hernandez, P. Hosseini, C. Ríos, C.D. Wright, & H. Bhaskaran. “Mixed‐Mode Electro‐Optical Operation of Ge2Sb2Te5 Nanoscale Crossbar Devices”. Advanced Electronic Materials, 3(8), 1700079, 2017.1
47. [OA] C. Ríos, P. Hosseini, R. Taylor, H. Bhaskaran. “Color depth modulation and resolution in phase-change material nanodisplays“. Advanced Materials. 28(23), 4720–4726, 2016.
48. M. Stegmaier, C. Ríos, H. Bhaskaran & W.H.P. Pernice. “Thermo-optical effect in phase-change nanophotonics”. ACS Photonics, 3(5), 828-835, 2016.
49. C. Ríos, M. Stegmaier, P. Hosseini, D. Wang, T. Scherrer, C.D. Wright, H. Bhaskaran, W.H.P. Pernice. “Integrated all-photonic non-volatile multi-level memory” Nature Photonics 9, 725-732, 2015.
    • Extensively featured across world media, reaching over 11,000 viewers in under 3 months and featured in over 50 news articles, including in MIT Technology Review, IFL science, and Science News. 
    • Ranked as top article of similar age in Nature Photonics (Altmetrics). 
    • News and views article in Nature Photonics “Optical memory: Phase-change memory” and OPN: “A Photonic Upgrade for Computer Memory?”
50. [OA] C. Ríos, P. Hosseini, CD. Wright, H. Bhaskaran, WHP. Pernice. “On-chip photonic memory elements employing phase change materials”. Advanced Materials 26(9), 1372-1377, 2014. 
51. [OA] J.F. Barrera, M. Tebaldi, C. Ríos, E. Rueda, N. Bolognini, R. Torroba.  “Experimental multiplexing of encrypted movies using a JTC architecture”. Opt. Express, Vol. 20 (4), 2012. 
52. E. Rueda, C. Ríos, J. F. Barrera, and R. Torroba. “Master key generation to avoid the use of an external reference wave in an experimental JTC encrypting architecture”. Applied Optics, Vol. 51 (11), 2012.
53. J.F. Barrera, E Rueda, C. Ríos, N. Bolognini, M. Tebaldi, R. Torroba, “Experimental opto-digital synthesis of encrypted sub-samples of an image to improve its decoded quality”. Optics Communications, Vol. 284 (19), 2011. 
54. E. Rueda, C. Ríos, J. F. Barrera, R. Henao and R. Torroba. “Experimental multiplexing approach via code key rotations under a joint transform correlator scheme”. Optics Communications, Vol. 284 (10),  2011.
55. [OA] C. A. Ríos, E.  Rueda & J.F. Barrera. “Sistema Óptico de Encriptación de Doble Máscara de Fase bajo Arquitectura 4f”. TecnoLógicas, Special edition II, 75-96, 2010.
56. C. A. Ríos-Ocampo, E. Rueda, & J.F. Barrera. “Análisis de la Sensibilidad de un Sistema óptico de Encriptación Bajo Rotaciones de la Llave de Seguridad”. Revista Colombiana de Física 42(2), 5, 2010.