Publications

Pierce C. Qureshi, Vincent Ng, Farhan Azeem, Luke S. Trainor, Harald G. L. Schwefel, Stéphane Coen, Miro Erkintalo, Stuart G. Murdoch. Kerr microresonator dual-comb source with adjustable line-spacing. Optics Express, 2023.

Mallika Suresh, Harald G. L. Schwefel, Dominik Walter Vogt. Gallium arsenide whispering gallery mode resonators for terahertz photonics. Optics Express, 2023.

Li Ma, Luke S. Trainor, Gavin G. G. King, Harald G. L. Schwefel, Jevon J. Longdell. Optically detected magnetic resonance to characterize atomlike microwave-optical transducers. Physical Review A, 2023.

Nicholas Lambert, Luke S. Trainor, Harald G. L. Schwefel. Microresonator-based electro-optic dual frequency comb. Communications Physics, 2023.

Vincent Ng, Farhan Azeem, Luke S. Trainor, Harald G. L. Schwefel, Stéphane Coen, Miro Erkintalo, Stuart G. Murdoch. Wideband multimode optical parametric oscillation in a Kerr microresonator. Optics Express, 2023.

Josh Christensen, Farhan Azeem, Luke S. Trainor, Dmitry v. Strekalov, Harald G. L. Schwefel. Distance calibration via Newton’s rings in yttrium lithium fluoride whispering gallery mode resonators. Optics Letters, 2022.

Pierce C. Qureshi, Vincent Ng, Farhan Azeem, Luke S. Trainor, Harald G. L. Schwefel, Stéphane Coen, Miro Erkintalo, Stuart G. Murdoch. Soliton linear-wave scattering in a Kerr microresonator. Communications Physics, 2022.

Daniel S. Norman, Farhan Azeem, Jevon J. Longdell, Harald G. L. Schwefel. Measuring optical loss in yttrium orthosilicate using a whispering gallery mode resonator. Materials for Quantum Technology, 2022.

Farhan Azeem, Luke S. Trainor, Ang Gao, Maya Isarov, Dmitry v. Strekalov, Harald G. L. Schwefel. Ultra-Low Threshold Titanium-Doped Sapphire Whispering-Gallery Laser. Advanced Optical Materials, 2022.

Nicholas Lambert, Harald G. L. Schwefel. Visualising the heart of chaos. Light: Science & Applications, 2021.

Sonia Mobassem, Nicholas Lambert, Alfredo Rueda, Johannes M. Fink, Gerd Leuchs, Harald G. L. Schwefel. Thermal noise in electro-optic devices at cryogenic temperatures. Quantum Science and Technology, 2021.

Farhan Azeem, Luke S. Trainor, Patrick A. Devane, Daniel S. Norman, Alfredo Rueda, Nicholas Lambert, Madhuri Kumari, Matthew R. Foreman, Harald G. L. Schwefel. Dielectric perturbations: anomalous resonance frequency shifts in optical resonators. Optics Letters, 2021.

M. D. E. Denys, M. K. Olsen, Luke S. Trainor, Harald G. L. Schwefel, A. S. Bradley. Steady states, squeezing, and entanglement in intracavity triplet down conversion. Optics Communications, 2020.

William Hease, Alfredo Rueda, Rishabh Sahu, Matthias Wulf, Georg Arnold, Harald G. L. Schwefel, Johannes M. Fink. Bidirectional Electro-Optic Wavelength Conversion in the Quantum Ground State. PRX Quantum, 2020.

Nicholas Lambert, A. A. Esmail, M. Edwards, A. J. Ferguson, Harald G. L. Schwefel. Random telegraph signal analysis with a recurrent neural network. Physical Review E, 2020.

Golnoush Shafiee, Dmitry v. Strekalov, Alexander Otterpohl, Florian Sedlmeir, Gerhard Schunk, Ulrich Vogl, Harald G. L. Schwefel, Gerd Leuchs, Christoph Marquardt. Nonlinear power dependence of the spectral properties of an optical parametric oscillator below threshold in the quantum regime. New Journal of Physics, 2020.

Ian Hendry, Luke S. Trainor, Yiqing Xu, Stéphane Coen, Stuart G. Murdoch, Harald G. L. Schwefel, Miro Erkintalo. Experimental observation of internally pumped parametric oscillation and quadratic comb generation in a $χ^(2)$ whispering-gallery-mode microresonator. Optics Letters, 2020.

Nicholas Lambert, Alfredo Rueda, Florian Sedlmeir, Harald G. L. Schwefel. Coherent Conversion Between Microwave and Optical Photons—An Overview of Physical Implementations. Advanced Quantum Technologies, 2020.

Alexander Otterpohl, Florian Sedlmeir, Ulrich Vogl, Thomas Dirmeier, Golnoush Shafiee, Gerhard Schunk, Dmitry v. Strekalov, Harald G. L. Schwefel, Tobias Gehring, Ulrik L. Andersen, Gerd Leuchs, Christoph Marquardt. Squeezed vacuum states from a whispering gallery mode resonator. Optica, 2019.

Noel Lito B. Sayson, Toby Bi, Vincent Ng, Hoan Pham, Luke S. Trainor, Harald G. L. Schwefel, Stéphane Coen, Miro Erkintalo, Stuart G. Murdoch. Octave-spanning tunable parametric oscillation in crystalline Kerr microresonators. Nature Photonics, 2019.

Alfredo Rueda, Florian Sedlmeir, Madhuri Kumari, Gerd Leuchs, Harald G. L. Schwefel. Resonant electro-optic frequency comb. Nature, 2019.

Dominik Walter Vogt, Angus Harvey Jones, Harald G. L. Schwefel, Rainer Leonhardt. Anomalous blue-shift of terahertz whispering-gallery modes via dielectric and metallic tuning. Optics Letters, 2019.

Dominik Walter Vogt, Angus Harvey Jones, Harald G. L. Schwefel, Rainer Leonhardt. Prism coupling of high-Q terahertz whispering-gallery-modes over two octaves from 0.2 THz to 1.1 THz. Optics Express, 2018.

Gabriel Santamaría Botello, Florian Sedlmeir, Alfredo Rueda, Kerlos Atia Abdalmalak, Elliott R. Brown, Gerd Leuchs, Sascha Preu, Daniel Segovia-Vargas, Dmitry v. Strekalov, Luis Enrique García Muñoz, Harald G. L. Schwefel. Sensitivity limits of millimeter-wave photonic radiometers based on efficient electro-optic upconverters. Optica, 2018.

Noel Lito B. Sayson, Hoan Pham, Karen E. Webb, Vincent Ng, Luke S. Trainor, Harald G. L. Schwefel, Stéphane Coen, Miro Erkintalo, Stuart G. Murdoch. Origins of clustered frequency combs in Kerr microresonators. Optics Letters, 2018.

Vladimir v. Kornienko, Galiya Kh. Kitaeva, Florian Sedlmeir, Gerd Leuchs, Harald G. L. Schwefel. Towards terahertz detection and calibration through spontaneous parametric down-conversion in the terahertz idler-frequency range generated by a 795 nm diode laser system. APL Photonics, 2018.

Luke S. Trainor, Florian Sedlmeir, Christian Peuntinger, Harald G. L. Schwefel. Selective Coupling Enhances Harmonic Generation of Whispering-Gallery Modes. Physical Review Applied, 2018.

Li Ge, Liang Feng, Harald G. L. Schwefel. Optical microcavities: new understandings and developments. Photonics Research, 2017.

Florian Sedlmeir, Matthew R. Foreman, Ulrich Vogl, Richard Zeltner, Gerhard Schunk, Dmitry v. Strekalov, Christoph Marquardt, Gerd Leuchs, Harald G. L. Schwefel. Polarization-Selective Out-Coupling of Whispering-Gallery Modes. Physical Review Applied, 2017.

Dmitry v. Strekalov, Christoph Marquardt, Andrey B. Matsko, Harald G. L. Schwefel, Gerd Leuchs. Nonlinear and quantum optics with whispering gallery resonators. Journal of Optics, 2016.

Gabriel A. Santamaría-Botello, Luis Enrique García Muñoz, Florian Sedlmeir, Sascha Preu, D. Segovia-Vargas, K. Atia Abdalmalak, S. Llorente Romano, A. García Lampérez, Stefan Malzer, Gottfried H. Döhler, Harald G. L. Schwefel, Heiko B. Weber. Maximization of the optical intra-cavity power of whispering-gallery mode resonators via coupling prism. Optics Express, 2016.

Matthew R. Foreman, Florian Sedlmeir, Harald G. L. Schwefel, Gerd Leuchs. Dielectric tuning and coupling of whispering gallery modes using an anisotropic prism. JOSA B, 2016.

Alfredo Rueda, Florian Sedlmeir, Michele C. Collodo, Ulrich Vogl, Birgit Stiller, Gerhard Schunk, Dmitry v. Strekalov, Christoph Marquardt, Johannes M. Fink, Oskar Painter, Gerd Leuchs, Harald G. L. Schwefel. Efficient microwave to optical photon conversion: an electro-optical realization. Optica, 2016.

Gerhard Schunk, Ulrich Vogl, Florian Sedlmeir, Dmitry v. Strekalov, Alexander Otterpohl, V. Averchenko, Harald G. L. Schwefel, Gerd Leuchs, Christoph Marquardt. Frequency tuning of single photons from a whispering-gallery mode resonator to MHz-wide transitions. Journal of Modern Optics, 2016.

Vittorio Peano, Harald G. L. Schwefel, Christoph Marquardt, Florian Marquardt. Intracavity Squeezing Can Enhance Quantum-Limited Optomechanical Position Detection through Deamplification. Physical Review Letters, 2015.

Gerhard Schunk, Ulrich Vogl, Dmitry v. Strekalov, Michael Förtsch, Florian Sedlmeir, Harald G. L. Schwefel, Manuela Göbelt, Silke Christiansen, Gerd Leuchs, Christoph Marquardt. Interfacing transitions of different alkali atoms and telecom bands using one narrowband photon pair source. Optica, 2015.

Michael Förtsch, Thomas Gerrits, Martin J. Stevens, Dmitry Strekalov, Gerhard Schunk, Josef U. Fürst, Ulrich Vogl, Florian Sedlmeir, Harald G. L. Schwefel, Gerd Leuchs, Sae Woo Nam, Christoph Marquardt. Near-infrared single-photon spectroscopy of a whispering gallery mode resonator using energy-resolving transition edge sensors. Journal of Optics, 2015.

Harald G. L. Schwefel, Hakan E. Türeci. A chaotic approach clears up imaging. Science, 2015.

A. Rivera-Lavado, Sascha Preu, Luis Enrique García Muñoz, A. Generalov, J. Montero-De-Paz, Gottfried H. Döhler, D. Lioubtchenko, M. Méndez-Aller, Florian Sedlmeir, Martin Schneidereit, Harald G. L. Schwefel, Stefan Malzer, D. Segovia-Vargas, A. v. Räisänen. Dielectric Rod Waveguide Antenna as THz Emitter for Photomixing Devices. IEEE Transactions on Antennas and Propagation, 2015.

Michael Förtsch, Gerhard Schunk, Josef U. Fürst, Dmitry Strekalov, Thomas Gerrits, Martin J. Stevens, Florian Sedlmeir, Harald G. L. Schwefel, Sae Woo Nam, Gerd Leuchs, Christoph Marquardt. Highly efficient generation of single-mode photon pairs from a crystalline whispering-gallery-mode resonator source. Physical Review A, 2015.

Gerhard Schunk, Josef U. Fürst, Michael Förtsch, Dmitry v. Strekalov, Ulrich Vogl, Florian Sedlmeir, Harald G. L. Schwefel, Gerd Leuchs, Christoph Marquardt. Identifying modes of large whispering-gallery mode resonators from the spectrum and emission pattern. Optics Express, 2014.

Florian Sedlmeir, Richard Zeltner, Gerd Leuchs, Harald G. L. Schwefel. High-Q MgF$_2$ whispering gallery mode resonators for refractometric sensing in aqueous environment. Optics Express, 2014.

Harald G. L. Schwefel. In optical pumping, less can be more. Science, 2014.

Frank Vollmer, Harald G. L. Schwefel. Taking detection to the limit with optical microcavities: Recent advances presented at the 560. WE Heraeus Seminar. The European Physical Journal Special Topics, 2014.

Richard Zeltner, Florian Sedlmeir, Gerd Leuchs, Harald G. L. Schwefel. Crystalline MgF$_2$ whispering gallery mode resonators for enhanced bulk index sensitivity. The European Physical Journal Special Topics, 2014.

Michele C. Collodo, Florian Sedlmeir, Benjamin Sprenger, Sergiy Svitlov, L. J. Wang, Harald G. L. Schwefel. Sub-kHz lasing of a CaF$_2$ whispering gallery mode resonator stabilized fiber ring laser. 2014.

Ingo Breunig, Boris Sturman, Florian Sedlmeir, Harald G. L. Schwefel, Karsten Buse. Whispering gallery modes at the rim of an axisymmetric optical resonator: Analytical versus numerical description and comparison with experiment. Optics Express, 2013.

Florian Sedlmeir, Martin Hauer, Josef U. Fürst, Gerd Leuchs, Harald G. L. Schwefel. Experimental characterization of an uniaxial angle cut whispering gallery mode resonator. Optics Express, 2013.

Sascha Preu, Sandra I. Schmid, Florian Sedlmeir, Jörg Evers, Harald G. L. Schwefel. Directional emission of dielectric disks with a finite scatterer in the THz regime. Optics Express, 2013.

Alex Kaplan, Matthew Tomes, Tal Carmon, Maxim Kozlov, Oren Cohen, Guy Bartal, Harald G. L. Schwefel. Finite element simulation of a perturbed axial-symmetric whispering-gallery mode and its use for intensity enhancement with a nanoparticle coupled to a microtoroid. Optics Express, 2013.

Maxim Kozlov, Ofer Kfir, Avner Fleischer, Alex Kaplan, Tal Carmon, Harald G. L. Schwefel, Guy Bartal, Oren Cohen. Narrow-bandwidth high-order harmonics driven by long-duration hot spots. New Journal of Physics, 2012.

Chang-Ling Zou, Harald G. L. Schwefel, Fang-Wen Sun, Zheng-Fu Han, Guang-Can Guo. Quick root searching method for resonances of dielectric optical microcavities with the boundary element method. Optics Express, 2011.

Mingying Peng, Benjamin Sprenger, Markus A. Schmidt, Harald G. L. Schwefel, Lothar Wondraczek. Broadband NIR photoluminescence from Bi-doped Ba$_2$P$_2$O$_7$ crystals: Insights into the nature of NIR-emitting Bismuth centers. Optics Express, 2010.

Benjamin Sprenger, Harald G. L. Schwefel, Z. H. Lu, Sergiy Svitlov, L. J. Wang. CaF$_2$ whispering-gallery-mode-resonator stabilized-narrow-linewidth laser. Optics Letters, 2010.

Benjamin Sprenger, Harald G. L. Schwefel, L. J. Wang. Whispering-gallery-mode-resonator-stabilized narrow-linewidth fiber loop laser. Optics Letters, 2009.

Harald G. L. Schwefel, Christopher G. Poulton. An improved method for calculating resonances of multiple dielectric disks arbitrarily positioned in the plane. Optics Express, 2009.

Dmitry v. Strekalov, Harald G. L. Schwefel, Anatoliy A. Savchenkov, Andrey B. Matsko, L. J. Wang, Nan Yu. Microwave whispering-gallery resonator for efficient optical up-conversion. Physical Review A, 2009.

Harald G. L. Schwefel, Wolfgang Köhler, Z. H. Lu, J. Fan, L. J. Wang. Direct experimental observation of the single reflection optical Goos-Hänchen shift. Optics Letters, 2008.

Tal Carmon, Harald G. L. Schwefel, Lan Yang, Mark Oxborrow, A. Douglas Stone, Kerry J. Vahala. Static envelope patterns in composite resonances generated by level crossing in optical toroidal microcavities. Physical Review Letters, 2008.

Sascha Preu, Harald G. L. Schwefel, Stefan Malzer, Gottfried H. Döhler, L. J. Wang, M. Hanson, J. D. Zimmerman, A. C. Gossard. Coupled whispering gallery mode resonators in the Terahertz frequency range. Optics Express, 2008.

Hakan E. Türeci, Harald G. L. Schwefel. An efficient Fredholm method for the calculation of highly excited states of billiards. Journal of Physics A, 2007.

Harald G. L. Schwefel, A. Douglas Stone, Hakan E. Türeci. Polarization properties and dispersion relations for spiral resonances of a dielectric rod. Journal of the Optical Society of America B, 2005.

Harald G. L. Schwefel, Nathan B. Rex, Hakan E. Türeci, Richard K. Chang, A. Douglas Stone, Tahar Ben-Messaoud, Joseph Zyss. Dramatic shape sensitivity of directional emission patterns from similarly deformed cylindrical polymer lasers. Journal of the Optical Society of America B, 2004.

Hakan E. Türeci, Harald G. L. Schwefel, A. Douglas Stone, Evgeniy Narimanov. Gaussian-optical approach to stable periodic orbit resonances of partially chaotic dielectric micro-cavities. Optics Express, 2002.

Nathan B. Rex, Hakan E. Türeci, Harald G. L. Schwefel, Richard K. Chang, A. Douglas Stone. Fresnel filtering in lasing emission from scarred modes of wave-chaotic optical resonators. Physical Review Letters, 2002.