Gaurav Bahl

For More Information

• MURI: Robust Photonics with High-Order Topological Protection
• Research group website

Education

• PhD, Electrical Engineering, Stanford University, September 2010
• MS, Electrical Engineering, Stanford University, June 2008
• B.Eng, Summa cum laude, Electrical Engineering, McMaster University, ON, Canada, June 2005

Academic Positions

• Affiliate, Department of Physics, University of Illinois at Urbana-Champaign, March 2020 - to date
• Affiliate, Illinois Quantum Information Science and Technology Center (IQUIST), Dec 2018 - to date.
• Associate Professor, Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, August 16, 2018 - to date
• Affiliate, Technology Entrepreneur Center, University of Illinois at Urbana-Champaign, May 5, 2017 - to date.
• Affiliate, Micro and Nanotechnology Laboratory, University of Illinois at Urbana-Champaign, January 16, 2013 - to date
• Affiliate, Department of Electrical & Computer Engineering, University of Illinois at Urbana-Champaign, August 16, 2012 - to date
• Assistant Professor, Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, August 16, 2012-2018
• Postdoctoral Research Fellow, EECS, Optics and Photonics Laboratory, University of Michigan, Ann Arbor, September 2010-August 2012
• Research Assistant, Mechanical Engineering, Micro-Structures and Sensors Laboratory, Stanford, April 2006-August 2010

Course Development

• Developed a new special topics class for mechanical engineers ME 498 PM4 "Photonic MEMS".

Research Statement

Gaurav Bahl performs experimental research at the interface between optical and mechanical systems. Of particular interest are the mechanisms by which light interacts mechanically with photonic microsystems (i.e. via radiation pressure, gradient force, electrostrictive pressure, and photothermal effects), and how mechanical devices can affect and manipulate light. Applications of this research include inertial sensors, microfluidic bio-chemical devices, microwave frequency references, and harsh-environment physical sensors.

While the forces exerted on matter by single photons are miniscule, micro/nanodevices that are both optically and mechanically resonant can enhance such opto-mechanical interactions by several orders-of-magnitude. These devices are excellent scientific platforms for research in nonlinear optics, quantum mechanics, laser development, and thermal management via laser heating and cooling.

Graduate Research Opportunities

PhD oriented Electrical Engineering graduate students with a strong background in experimental optics are encouraged to contact Prof. Bahl with a complete CV.

Undergraduate Research Opportunities

Research Topics

• Charge particle physics and engineering
• Electronics, Plasmonics, and Photonics
• Micro & nanoelectromechanical M/NEMS integrated systems
• Photonics: optical engineering and systems
• RF and microwave engineering

Chapters in Books

• N.T. Otterstrom, E.A. Kittlaus, D.B. Sohn, G. Bahl, "Non-reciprocity in Brillouin scattering," in Semiconductors and Semimetals vol 109, Brillouin Scattering Part 1. Eds: B.J. Eggleton, M. Steel, C.G. Poulton, Elsevier, 2022, ISSN 0080-8784, ISBN 978-03-239-89299 doi:10.1016/bs.semsem.2022.05.006

Selected Articles in Journals

• C.J. Flower, M.J. Mehrabad, L. Xu, G. Moille, D.G. Suarez-Forero, O.E. Örsel, G. Bahl, Y. Chembo, K. Srinivasan, S. Mittal, M. Hafezi, "Observation of topological frequency combs," Science 384, 6702, pp.1356-1361, 2024.
• J. Jing, G. Bahl, "Simultaneous maximization of voltage and power efficiencies in magneto-mechanical transmitters," IEEE Transactions on Antennas and Propagation 72(2), pp.1617-1623, 2023.
• O.E. Orsel, J. Noh, G. Bahl, "Electrically-controlled suppression of Rayleigh backscattering in an integrated photonic circuit," Nanophotonics 13(2), pp.173-181, 2024.
• A. Stegmaier, H. Brand, S. Imhof, A. Fritzsche, T. Helbig, T. Hofmann, I. Boettcher, M. Greiter, C.H. Lee, G. Bahl, A. Szameit, T. Kießling, R. Thomale, L.K. Upreti, "Realizing efficient topological temporal pumping in electrical circuits," Phys. Rev. Research 6, 023010, 2024.
• O.E. Orsel, G. Bahl, "Electro-optic non-reciprocal polarization rotation in lithium niobate," APL Photonics 8, 096107, 2023.
• J. Jing, S. Tawfick, G. Bahl, "Frequency response and eddy current power loss in magneto-mechanical transmitters," IEEE Transactions on Antennas and Propagation 71(4), pp.3642-3653, 2023.
• P. Zhu, X.-Q. Sun, T.L. Hughes, G. Bahl, "Higher rank chirality and non-Hermitian skin effect in a topolectrical circuit," Nature Communications 14, 720, doi: 10.1038/s41467-023-36130-x, 2023.
• J. Schulz*, J. Noh*, W.A. Benalcazar, G. Bahl, G. von Freymann [* equal contribution], "Photonic quadrupole topological insulator using orbital-induced synthetic flux," Nature Communications 13, 6597, 2022.
• G. Liu, J. Noh, J. Zhao, G. Bahl, "Self-Induced Dirac Boundary State and Digitization in a Nonlinear Resonator Chain," Physical Review Letters, 129, 135501, 2022.
• A. Kanj, R.P. Thanalakshme, C. Li, J. Kulikowski, G. Bahl, S. Tawfick, "Design, Dynamics, and Dissipation of a Torsional-Magnetic Spring Oscillator," (accepted) Mechanical Systems and Signal Processing, 2022. arXiv preprint: 2112.13806
• S.S. Yamada, T. Li, M. Lin, C.W. Peterson, T.L. Hughes, G. Bahl, "Bound states at partial dislocation defects in multipole higher-order topological insulators," Nature Communications 13:2035, doi:10.1038/s41467-022-29785-5, 2022.
• R.P. Thanalakshme, A. Kanj, J. Kim, E. Wilken-Resman, J. Jing, I.H. Grinberg, J.T. Bernhard, S. Tawfick, G. Bahl, "Magneto-Mechanical Transmitters for Ultra-Low Frequency Near-field Communication," IEEE Transactions on Antennas and Propagation, doi:10.1109/TAP.2021.3137244, 2021
• D.B. Sohn, O.E. Orsel, G. Bahl, "Electrically driven optical isolation through phonon mediated photonic Autler-Townes splitting," Nature Photonics 15, pp.822–827, doi:10.1038/s41566-021-00884-x, 2021. *Featured as hero image for Nov 2021.
• S. Kim, G. Bahl, "Exceptional behaviour without exceptional effort," Nature Photonics 15, pp.556–557, doi:10.1038/s41566-021-00849-0, 2021.
• C. W. Peterson, T. Li, W. Jiang, T.L. Hughes, G. Bahl, "Trapped fractional charges at bulk defects in topological insulators," Nature 589, pp.376-380, 2021.
• S. Kim, D.B. Sohn, C.W. Peterson, G. Bahl, “On-chip optical non-reciprocity through a synthetic Hall effect for photons,” APL Photonics 6, 011301, 2021. * Selected as Editor’s Pick
• I.H. Grinberg, M. Lin, W.A. Benalcazar, T.L. Hughes, G. Bahl, "Observation of a trapped state at a dislocation in a weak magneto-mechanical topological insulator," Phys. Rev. Applied 14, 064042, 2020. *Selected as Editor's Suggestion.
• C. W. Peterson, T. Li, W. A. Benalcazar, T.L. Hughes, G. Bahl, "A fractional corner anomaly reveals higher-order topology," Science, vol. 368, iss. 6495, pp. 1114-1118, 2020.
• I. H. Grinberg, M. Lin, C. Harris, W. A. Benalcazar, C. W. Peterson, T. L. Hughes, G. Bahl, "Robust temporal pumping in a magneto-mechanical topological insulator," Nature Communications 11:974, 2020.
• D.B. Sohn, G. Bahl, "Direction reconfigurable non-reciprocal acousto-optic modulator on chip," APL Photonics 4, 126103, 2019.
• S. Kim, J.M. Taylor, G. Bahl, "Dynamic suppression of Rayleigh light scattering in dielectric resonators," Optica 6(8), pp. 1016-1022, 2019.
• C. W. Peterson, W. A. Benalcazar, M. Lin, T. L. Hughes, G. Bahl, "Strong nonreciprocity in modulated resonator chains through synthetic electric and magnetic fields," Physical Review Letters, 123, 063901, 2019.
• B. J. Eggleton, C. G. Poulton, P. T. Rakich, M. J. Steel, G. Bahl, "Brillouin integrated photonics," Nature Photonics 13, pp.664–677, doi:10.1038/s41566-019-0498-z, 2019.
• I.H. Grinberg, A. Mangu, C. W. Peterson, E. Wilken-Resman, J. T. Bernhard, G. Bahl, "Magnetostatic spring softening and stiffening in magneto-mechanical resonator systems," IEEE Transactions on Magnetics, doi:10.1109/TMAG.2019.2906864, 2019
• K. Han, J. Suh, G. Bahl, "Optomechanical non-contact measurement of microparticle compressibility in liquids," Optics Express 26(24), pp. 31908-31916 (2018), 2018.
• Peterson, C.W., S. Kim, J.T. Bernhard, and G. Bahl, "Reconfigurable arbitrary nonreciprocal transfer functions through nonreciprocal coupling," Science Advances 4(6), eaat0232, doi:10.1126/sciadv.aat0232, 2018.
• Chen, Y.-C. I. Ghosh, A. Schleife, P.S. Carney, and G. Bahl, “Optimization of anisotropic photonic density of states for Raman cooling,” Phys. Rev. A 97, 043835, 2018.
• C.W. Peterson, W.A. Benalcazar, T.L. Hughes, G. Bahl, "Demonstration of a quantized microwave quadrupole insulator with topologically protected corner states," Nature 555, pp.346–350, doi:10.1038/nature25777, 2018.
• J. Suh, K. Han, G. Bahl, "Imaging of acoustic pressure modes in opto-mechano-fluidic resonators with a single particle probe," Applied Physics Letters, 112, 071106, 2018.
• D.B. Sohn, S. Kim, G. Bahl, "Time-reversal symmetry breaking with acoustic pumping of nanophotonic circuits," Nature Photonics 12, pp.91-97, doi:10.1038/s41566-017-0075-2 (2018) *Cover article
• Kim, S., X. Xu, J.M. Taylor, and G. Bahl, “Dynamically induced robust phonon transport and chiral cooling in an optomechanical system,” Nature Communications 8, 205, doi:10.1038/s41467-017-00247-7, 2017.
• Kim*, J., S. Kim*, and G. Bahl [* equal contribution], "Complete linear optical isolation at the microscale with ultralow loss," Scientific Reports, 7:1647, doi:10.1038/s41598-017-01494-w, 2017.
• Kim, S. and G. Bahl, "Role of optical density of states in two-mode optomechanical cooling," Optics Express 25(2), pp.776-784, 2017.
• Suh, J., K. Han, C.W. Peterson, and G. Bahl, "Real-time sensing of flowing nanoparticles with electro-opto-mechanics," APL Photonics 2, 010801, doi:10.1063/1.4972299, 2017.
• Chen, Y.-C., S. Kim, and G. Bahl, "Brillouin Cooling in a Linear Waveguide," New Journal of Physics, 18, 115004, 2016.
• Bahl, G., "Raman cooling in a semiconductor (News & Views)," Nature Photonics 10, pp.566-567, doi:10.1038/nphoton.2016.142, July 2016.
• Han, K., J. Kim, and G. Bahl, "High-Throughput Sensing of Freely Flowing Particles with OptoMechanoFluidics," Optica 3(6), pp. 585-591, doi:10.1364/OPTICA.3.000585, 2016. *Cover article.
• Dostart, N., S. Kim, and G. Bahl, "Giant Gain Enhancement in Surface-Confined Resonant Stimulated Brillouin Scattering," Laser & Photonics Reviews, doi:10.1002/lpor.201500141, 2015.
• Chen, Y.-C. and G. Bahl, "Raman Cooling of Solids through Photonic Density of States Engineering," Optica 2(10), pp.893-899, doi:10.1364/OPTICA.2.000893, 2015.
• Kim, J., M. Kuzyk, K. Han, H. Wang, and G. Bahl, "Non-reciprocal Brillouin scattering induced transparency," Nature Physics 11, pp.275-280, doi:10.1038/nphys3236, 2015.
• Zhu, K., K. Han, T. Carmon, X. Fan, and G. Bahl, "Opto-Acoustic Biosensing with Optomechanofluidic Resonators," European Physical Journal Special Topics, 223, 1937-1947, 2014.
• Gartia, M.R., S. Seo, J. Kim, T.-W. Chang, G. Bahl, M. Lu, G.L. Liu, and J.G. Eden, "Injection-Seeded Optoplasmonic Amplifier in the Visible," Scientific Reports 4, 6168, doi:10.1038/srep06168, 2014.
• Han, K., K. Zhu, and G. Bahl, "Opto-Mechano-Fluidic Viscometer," Applied Physics Letters, 105, 014103, 2014.
• Han, K., K.H. Kim, J. Kim, W. Lee, J. Liu, X. Fan, T. Carmon, and G. Bahl, "Fabrication and testing of microfluidic optomechanical oscillators," Journal of Visualized Experiments, vol.87, e51497, doi:10.3791.51497, 2014.
• Han,, K., J. Kim, and G. Bahl, "Aerostatically tunable optomechanical oscillators," Optics Express, vol. 22, issue 2, pp. 1267-1276, 2014.
• Kim, K. H.*, G. Bahl*, W. Lee, J. Liu, M. Tomes, X. Fan, T. Carmon [* = equal contribution], "Cavity Optomechanics on a Microfluidic Resonator," Light: Science & Applications, vol. 2, e110; doi:10.1038/lsa.2013.66, 2013.
• Bahl, G., K. H. Kim, W. Lee, J. Liu, X. Fan, and T. Carmon, "Brillouin cavity optomechanics with microfluidic devices," Nature Communications, 4:1994, doi:10.1038/ncomms2994, 2013.
• Bahl, G., X. Fan, and T. Carmon, "Acoustic Whispering-Gallery Modes in Optomechanical Shells," New Journal of Physics, Vol. 14, 115026, 2012.
• Bahl, G., M. Tomes, F. Marquardt, and T. Carmon, “Observation of Spontaneous Brillouin Cooling,” Nature Physics, doi:10.1038/nphys2206, 2012.
• Tomes, M., F. Marquardt, G. Bahl, and T. Carmon, “Quantum Mechanical Theory of Optomechanical Brillouin Cooling,” Physical Review A, 84, 063806, 2011.
• Bahl, G., J. Zehnpfennig, M. Tomes, and T. Carmon, “Stimulated Optomechanical Excitation of Surface Acoustic Waves in a Microdevice,” Nature Communications, 2:403, doi:10.1038/ncomms1412, 2011.
• Zehnpfennig, J., G. Bahl, M. Tomes, and T. Carmon, “Surface Optomechanics: Calculating Optically Excited Acoustical Whispering Gallery Modes in Microspheres,” Optics Express, Vol. 19, pp.14240-8, 2011.
• Bahl, G., J. Salvia, R. Melamud, B. Kim, R.T. Howe, and T. W. Kenny, “AC Polarization for Charge-Drift Elimination in Resonant Electrostatic MEMS and Oscillators,” Journal of Microelectromechanical Systems, Vol. 20, No. 2, April 2011.
• Yoneoka, S., J. Salvia, G. Bahl, R. Melamud, S. A. Chandorkar, and T. W. Kenny, “Active Electrostatic Compensation of Micromechanical Resonators Under Random Vibrations,” JMEMS Letters, Vol. 19, No. 5, October 2010.
• Bahl, G., R. Melamud, B. Kim, S. A. Chandorkar, J. Salvia, M. A. Hopcroft, D. Elata, R. G. Hennessy, R. N. Candler, R.T. Howe, and T. W. Kenny, “Model and Observations of Dielectric Charge in Thermally Oxidized Silicon Resonators,” Journal of Microelectromechanical Systems, Vol. 19, No. 1, Feb 2010.
• Melamud, R., S. A. Chandorkar, B. Kim, H. K. Lee, J. Salvia, G. Bahl, M. A. Hopcroft, and T. W. Kenny, “Temperature Insensitive Composite Micromechanical Resonators,” Journal of Microelectromechanical Systems, Vol. 18, No. 6, Dec 2009.
• Agarwal, M., S. A. Chandorkar, H. Mehta, R. N. Candler, B. Kim, M. A. Hopcroft, R. Melamud, C. M. Jha, G. Bahl, G. Yama, T. W. Kenny, and B. Murmann, “A Study of Electrostatic Force Nonlinearities in Resonant Microstructures,” Applied Physics Letters, Vol. 92, pp. 104106-3, 2008.
• Agarwal, M., H. Mehta, R. N. Candler, S. A. Chandorkar, B. Kim, M. A. Hopcroft, R. Melamud, G. Bahl, G. Yama, T. W. Kenny, and B. Murmann, “Scaling of Amptitude-Frequency-Dependence Nonlinearities in Electrostatically Transduced Microresonators,” Journal of Applied Physics, Vol. 102, p. 74903, 2007.
• Jha, C. M., G. Bahl, R. Melamud, S. A. Chandorkar, M. A. Hopcroft, B. Kim, M. Agarwal, J. Salvia, H. Mehta, and T. W. Kenny, "High Resolution Microresonator-Based Digital Temperature Sensor, "Applied Physics Letters, Vol. 91, p. 74101, 2007.
• Hopcroft, M. A., B. Kim, S. Chandorkar, R. Melamud, M. Agarwal, C. M. Jha, G. Bahl, J. Salvia, H. Mehta, H. K. Lee, R. N. Candler, and T. W. Kenny, "Using The Temperature Dependence of Resonator Quality Factor as a Thermometer," Applied Physics Letters, Vol. 91, p. 013505, 2007.

Articles in Conference Proceedings

• I. Grinberg, M. Lin, W. Benalcazar, T. Hughes, G. Bahl, "Magneto-Mechanical Topological Lego," at APS March Meeting, Los Angeles, 2018.
• C. Peterson, W. Benalcazar, T. Hughes, G. Bahl, "Measurement of topologically protected corner states in a microwave metamaterial quadrupole insulator," at APS March Meeting, Los Angeles, 2018.
• Sohn, D., S. Kim, and G. Bahl, "Piezo-optomechanical nonreciprocal modulator," Workshop on Optomechanics and Brillouin Scattering: Fundamentals, Applications and Technology (WOMBAT), Besancon, France, July 2017.
• Suh, J., K. Han, C.W. Peterson, and G. Bahl, "High-throughput real-time sensing with microfluidic electro-opto-mechanical resonators," at SPIE Photonics West, Feb 2017.
• Peterson, C.W., J.T. Bernhard, and G. Bahl, "Toward lossless nonreciprocity through spatiotemporal modulation," at Nanometa 2017, Seefeld, Austria, Jan 2017.
• Zhang, Z., S. Shi, K. Han, G. Bahl, and S. Tawfick, "Flexible Transparent Conductor/Strain Sensors from Downsizing Traditional Metallic Wires to the Nanoscale," MRS Conference Spring, April 2015.
• Ng, E., Y. Yang, V.A. Hong, C.H. Ahn, D.B. Heinz, I. Flader, Y. Chen, C.L.M. Everhart, B. Kim, R. Melamud, R.N. Candler, M.A. Hopcroft, J.C. Salvia, S. Yoneoka, A.B. Graham, M. Agarwal, M.W. Messana, K.L. Chen, H.K. Lee, S. Wang, G. Bahl, V. Qu, C.F. Chiang, T.W. Kenny, A. Partridge, M. Lutz, G. Yama, and G.J. O'Brien, "The long path from MEMS resonators to timing products," Proc. 28th IEEE MEMS 2015, Estoril, Portugal, 18-22 Jan 2015.

Pending Articles

• C. Li, A. Kanj, J. Jing, G. Bahl, S. Tawfick, "Pivot Bearings for Efficient Torsional Magneto-Mechanical Resonators," arXiv:2410.14855, 2024.
• O.E. Orsel, J. Noh, P. Zhu, J. Yim, T.L. Hughes, R. Thomale, G. Bahl, "Giant non-reciprocity and gyration through modulation-induced Hatano-Nelson coupling in integrated photonics," arXiv:2410.10079, 2024.
• J. Jing, G. Bahl, "An adaptive driving circuit for magneto-mechanical transmitters," techRxiv, doi: 10.36227/techrxiv. 172792935.51503108/v1, 2024.
• G. Liu, V. Workman, J. Noh, Y. Ma, T.L. Hughes, W.A. Benalcazar, G. Bahl, "A mono-atomic orbital-based 1D topological crystalline insulator," arXiv:2310.10403, 2023.

Patents

• US Patent # 10,693,206. June 23, 2020, "Nonreciprocal devices having reconfigurable nonreciprocal transfer functions through nonreciprocal coupling." Authors: Gaurav Bahl, Christopher Peterson.
• US Patent # 10,693,524. June 23, 2020, "System and Method for Mechanically-Based Magnetic-Field Transmitter." Authors: Gaurav Bahl, Sameh Tawfick, Rhinithaa P. Thanalakshme, Ali Kanj, Inbar Grinberg, Jennifer Bernhard.
• US Patent # 10,690,856, June 23, 2020, "Breaking Time-Reversal Symmetry with Acoustic Pumping of Nanophotonic Circuits." Authors: Gaurav Bahl, Donggyu Benjamin Sohn
• US Patent # 10,234,444. March 19, 2019. System and Method for nano-opto-mechanical-fluidic Sensing of Particles. Authors: Gaurav Bahl, Kewen Han.
• US Patent # 9,594,257. Mar 14, 2017, "System and Method for Brillouin Scattering Induced Transparency" Authors: Gaurav Bahl, JunHwan Kim, Hailin Wang, Mark Kuzyk.

Journal Editorships

• Associate Editor for Optica, Feb 2023 - Jan 2026 (3-year term)
• Editorial Advisory Board for APL Photonics, Jan 2019 - Dec 2021 (3-year term)

Professional Societies

• Member, ASME, 2016-date
• Member, SPIE, 2014-date
• Fellow, Optica (formerly OSA), Member: 2010-2020, Senior member: 2020-2023. Fellow: 2023-Present.
• Senior Member, Institute of Electrical and Electronics Engineers (IEEE), Member: 2009-2016, Senior member: 2016-Present

Research Honors

• 2022 Fellow of Optica (formerly OSA)
• 2019 Presidential Early Career Award for Scientists and Engineers (PECASE)
• 2018 Deans Award for Excellence in Research
• 2017 Office of Naval Research (ONR) Director of Research Early Career Grant
• 2015 Air Force Young Investigator Program (YIP) award for Chip-Scale Linear Non-Reciprocal Optomechanical Systems.

Other Honors

• George B. Grim Professor in Mechanical Science and Engineering (Feb 2023)
• Fellow of Optica (Oct 2022)

Recent Courses Taught

• ME 360 AL1 (ME 360 AL2) - Signal Processing
• ME 370 - Mechanical Design I
• ME 487 - MEMS-NEMS Theory & Fabrication
• ME 598 GB1 - Emergent Phenomena w/photons