Marc-Antoine Lemonde, Srujan Meesala, Alp Sipahigil, Martin J. A. Schuetz, Mikhail D. Lukin, Marko Loncar, and Peter Rabl. Submitted. “Phonon networks with SiV centers in diamond waveguides.” arXiV pre-print, 1801.01904. Publisher's Version Main text Supplementary
Srujan Meesala*, Young-Ik Sohn*, and et al. Submitted. “Strain engineering of the silicon vacancy center in diamond.” arXiV pre-print, 1801.09833. Publisher's VersionAbstract
We control the electronic structure of the silicon-vacancy (SiV) color-center in diamond by changing its static strain environment with a nano-electro-mechanical system. This allows deterministic and local tuning of SiV optical and spin transition frequencies over a wide range, an essential step towards multi-qubit networks. In the process, we infer the strain Hamiltonian of the SiV revealing large strain susceptibilities of order 1 PHz/strain for the electronic orbital states. We identify regimes where the spin-orbit interaction results in a large strain suseptibility of order 100 THz/strain for spin transitions, and propose an experiment where the SiV spin is strongly coupled to a nanomechanical resonator.
Zin Lin, Benedikt Groever, Federico Capasso, Alejandro W. Rodriguez, and Marko Lončar. Submitted. “Topology Optimized Multi-layered Meta-optics.” arXiv:1706.06715. Publisher's Version [PDF]
Young-Ik Sohn*, Srujan Meesala*, Benjamin Pingault*, Haig A. Atikian, Jeffrey Holzgrafe, Mustafa Gündoğan, Camille Stavrakas, Megan J. Stanley, Alp Sipahigil, Joonhee Choi, Mian Zhang, Jose L. Pacheco, John Abraham, Edward Bielejec, Mikhail D. Lukin, Mete Atatüre, and Marko Lončar. Submitted. “Controlling the coherence of a diamond spin qubit through strain engineering.” arXiv:1706.03881. arXiv VersionAbstract
The uncontrolled interaction of a quantum system with its environment is detrimental for quantum coherence. In the context of solid-state qubits, techniques to mitigate the impact of fluctuating electric and magnetic fields from the environment are well-developed. In contrast, suppression of decoherence from thermal lattice vibrations is typically achieved only by lowering the temperature of operation. Here, we use a nano-electro-mechanical system (NEMS) to mitigate the effect of thermal phonons on a solid-state quantum emitter without changing the system temperature. We study the silicon-vacancy (SiV) colour centre in diamond which has optical and spin transitions that are highly sensitive to phonons. First, we show that its electronic orbitals are highly susceptible to local strain, leading to its high sensitivity to phonons. By controlling the strain environment, we manipulate the electronic levels of the emitter to probe, control, and eventually, suppress its interaction with the thermal phonon bath. Strain control allows for both an impressive range of optical tunability and significantly improved spin coherence. Finally, our findings indicate that it may be possible to achieve strong coupling between the SiV spin and single phonons, which can lead to the realisation of phonon-mediated quantum gates and nonlinear quantum phononics.
Main text Supplementary material
Zin Lin, Lysander Christakis, Yang Li, Eric Mazur, Alejandro W. Rodriguez, and Marko Lončar. Submitted. “Topology-optimized Dual-Polarization Dirac Cones.” arXiv:1705.03574. Publisher's Version [PDF]
Jingyuan Linda Zhang, Shuo Sun, Michael J Burek, Constantin Dory, Yan-Kai Tzeng, Kevin A Fischer, Yousif Kelaita, Konstantinos G Lagoudakis, Marina Radulaski, Zhi-Xun Shen, Nicholas A Melosh, Steven Chu, Marko Loncar, and Jelena Vuckovic. 1/29/2018. “Strongly Cavity-Enhanced Spontaneous Emission from Silicon-Vacancy Centers in Diamond.” Nano Letters, 18, 2, Pp. 1360-1365. Publisher's Version acs.nanolett.7b05075.pdf
Cheng Wang, Mian Zhang, Brian Stern, Michal Lipson, and Marko Loncar. 1/22/2018. “Nanophotonic Lithium Niobate Electro-optic Modulators.” Optics Express, 26, 2, Pp. 1547-1555. Publisher's Version [PDF]
Pawel Latawiec, Vivek Venkataraman, Amirhassan Shams-Ansari, Matthew Markham, and Marko Loncar. 1/15/2018. “An integrated diamond Raman laser pumped in the near-visible.” Optics Letters Vol. 43, Issue 2, pp. 318-321 (2018). arXiv VersionAbstract
Using a high-Q diamond microresonator (Q > 300,000) interfaced with high-power-handling directly-written doped-glass waveguides, we demonstrate a Raman laser in an integrated platform pumped in the near-visible. Both TM-to-TE and TE-to-TE lasing is observed, with a Raman lasing threshold as low as 20 mW and Stokes power of over 1 mW at 120 mW pump power. Stokes emission is tuned over a 150 nm (60 THz) bandwidth around 875 nm wavelength, corresponding to 17.5% of the center frequency.
Mian Zhang, Cheng Wang, Rebecca Cheng, Amirhassan Shams-Ansari, and Marko Loncar. 12/18/2017. “Monolithic Ultrahigh-Q Lithium Niobate Microring Resonator.” Optica, 4, 12, Pp. 1536-1537. Publisher's Version [PDF]
Cheng Wang, Zhaoyi Li, Myoung-Hwan Kim, Xiao Xiong, Xi-Feng Ren, Guang-Can Guo, Nanfang Yu, and Marko Loncar. 12/13/2017. “Metasurface-assisted phase-matching-free second harmonic generation in lithium niobate waveguides.” Nature Communications, 8, Pp. 2098. Publisher's Version [PDF]
Young-Ik Sohn, Rachel Miller, Vivek Venkataraman, and Marko Lončar. 12/2017. “Mechanical and optical nanodevices in single-crystal quartz.” Applied Physics Letters, 111, Pp. 263103. Publisher's VersionAbstract

Single-crystal α-quartz, one of the most widely used piezoelectric materials, has enabled a wide range of timing applications. Owing to the fact that integrated thin-film based quartz platform is not available, most of these applications rely on macroscopic, bulk crystal-based devices. Here we show that the Faraday cage angled-etching technique can be used to realize nanoscale electromechanical and photonic devices in quartz. Using this approach, we demonstrate quartz nanomechanical cantilevers and ring resonators featuring Qs of 4,900 and 8,900, respectively.

Stefan Bogdanovic, Madelaine S.Z. Liddy, Suzanne B. van Dam, Lisanne C. Coenen, Thomas Fink, Marko Loncar, and Ronald Hanson. 11/1/2017. “Robust nano-fabrication of an integrated platform for spin control in a tunable microcavity.” APL Photonics, 2, Pp. 126101. Publisher's Version [PDF]
Xuefeng Jiang, Linbo Shao, Shu-Xin Zhang, Xu Yi, Jan Wiersig, Li Wang, Qihuang Gong, Marko Loncar, Lan Yang, and Yun-Feng Xiao. 10/19/2017. “Chaos-assisted broadband momentum transformation in optical microresonators.” Science, 358, 6361, Pp. 344–347. Publisher's Version [PDF]
Orad Reshef, Philip Camayd-Muñoz, Daryl I. Vulis, Yang Li, Marko Lonc̆ar, and Eric Mazur. 10/9/2017. “Direct Observation of Phase-Free Propagation in a Silicon Waveguide.” ACS Photonics, 4, 10, Pp. 2385–2389. Publisher's Version [PDF]
Mohammad Soltani, Mian Zhang, Colm Ryan, Guilhem J. Ribeill, Cheng Wang, and Marko Loncar. 10/5/2017. “Efficient quantum microwave-to-optical conversion using electro-optic nanophotonic coupled resonators.” Physical Review A, 96, Pp. 043808. Publisher's Version [PDF]
Michael J. Burek, Charles Meuwly, Ruffin E. Evans, Mihir K. Bhaskar, Alp Sipahigil, Srujan Meesala, Bartholomeus Machielse, Denis D. Sukachev, Christian T. Nguyen, Jose L. Pacheco, Edward Bielejec, Mikhail D. Lukin, and Marko Lončar. 8/25/2017. “Fiber-Coupled Diamond Quantum Nanophotonic Interface.” Physical Review Applied, 8, 2, Pp. 024026. Publisher's Version physrevapplied.8.024026.pdf
Zin Lin, Marko Lončar, and Alejandro W. Rodriguez. 7/13/2017. “Topology optimization of multi-track ring resonators and 2D microcavities for nonlinear frequency conversion.” Optics Letters, 42, 14, Pp. 2818-2821. Publisher's Version [PDF]
Mihir K. Bhaskar, Denis D. Sukachev, Alp Sipahigil, Ruffin E. Evans, Michael J. Burek, Christian T. Nguyen, Lachlan J. Rogers, Petr Siyushev, Mathias H. Metsch, Hongkun Park, Fedor Jelezko, Marko Lončar, and Mikhail D. Lukin. 5/31/2017. “Quantum Nonlinear Optics with a Germanium-Vacancy Color Center in a Nanoscale Diamond Waveguide.” Physical Review Letters, 118, Pp. 223603. Publisher's Version [PDF]
Daryl I. Vulis, Yang Li, Orad Reshef, Philip Camayd-Muñoz, Mei Yin, Shota Kita, Marko Lončar, and Eric Mazur. 5/29/2017. “Monolithic CMOS-compatible zero-index metamaterials.” Optics Express, 25, 11, Pp. 12381-12399. Publisher's Version [PDF]
Carmen Palacios-Berraquero, Dhiren M. Kara, Alejandro R.-P. Montblanch, Matteo Barbone, Pawel Latawiec, Duhee Yoon, Anna K. Ott, Marko Lončar, Andrea C. Ferrari, and Mete Atature. 5/22/2017. “Large-scale quantum-emitter arrays in atomically thin semiconductors.” Nature Communications, 8, Pp. 15093. Publisher's Version [PDF]