Interview conducted by Louis CastelFeb 3 2026AZoOptics speaks with Feng Pan from Stanford University about his team’s recent advance: a room-temperature spin–photon interface that merges silicon nanophotonics with atomically thin semiconductors. Feng explains how carefully engineered nanostructure symmetries enable stable electron–photon entanglement without the need for cryogenic cooling. He also discusses the pivotal role of MoSe2 in the system’s performance, and what this development could mean for building scalable quantum communication systems and future hybrid quantum networks.
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Could you briefly explain what your new room-temperature quantum communication device does and why operating at room temperature is such a key milestone for the field?
This new nanoscale optical device combines silicon photonics with atomically thin semiconductors to entangle the spins of photons and electrons. This approach enables record-high photonic performance, including highly efficient spin control of photons and strong light-matter interactions with electrons, and efficient photon extraction, all achieved at room temperature.
In atomically thin semiconductors, the spins of electrons, once optically addressed, typically lose coherence within one trillionth of a second at room temperature. Being able to operate efficiently without cryogenics, therefore, represents a major milestone: it significantly reduces cost and system complexity and makes large-scale deployment far more realistic, particularly for quantum communication and quantum computing.
What specific physical mechanisms in your device help stabilize the electron spin state long enough to be useful for quantum signaling?
The key physical mechanism is the deliberate engineering of structural symmetries - specifically mirror and inversion symmetries - in silicon nanostructures. By tailoring these symmetries, we create chiral electromagnetic fields that allow the spin angular momentum of photons to be efficiently and selectively transferred to the spin states of electrons in the semiconductor.
In addition, the use of high-quality crystalline silicon thin films, together with high-precision nanofabrication, minimizes optical loss and disorder that would otherwise introduce spin dephasing. Careful preparation and integration of atomically thin semiconductor monolayers further preserve intrinsic spin–valley selection rules and ensure strong, coherent light–matter coupling. Taken together, these factors stabilize the electron spin state long enough to enable robust quantum signaling at room temperature.
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Transition metal dichalcogenides have been explored widely in quantum optics; what made MoSe2 the right choice here, and what trade-offs or advantages did you observe compared with other TMDCs or 2D materials?
MoSe2 was chosen primarily because it exhibits some of the best photoluminescence properties among transition metal dichalcogenides, which is critical for high-fidelity optical spin initialization and readout. Its narrow excitonic linewidths and high radiative efficiency enable strong light–matter interactions and robust optical spin–valley selectivity, making it particularly well suited for photonic quantum optics experiments.
The trade-off is that MoSe2 does not offer the most favorable electrical properties among TMDCs. In particular, charge carrier injection and electrostatic control are generally more efficient in materials such as WS2 or MoS2. For this reason, while MoSe2 is ideal for demonstrating optically driven spin–photon transduction, we anticipate that WS2 or MoS2 may be better candidates for future studies focused on electro-optic spin transduction or electrically driven quantum devices.
From a devices and integration standpoint, how compatible is your approach with existing silicon photonics and CMOS fabrication workflows? What are the main challenges to scaling this from a lab prototype to a wafer-scale technology?
From a fabrication standpoint, our approach is highly compatible with existing silicon photonics and CMOS workflows. We begin by bonding a 4-inch silicon-on-insulator wafer to a glass wafer, followed by nanopatterning using electron-beam lithography and standard dry and wet etching to define the silicon nanostructures. These processes rely on well-established silicon fabrication techniques and can be readily translated to deep-UV or extreme-UV lithography and scaled up in commercial foundries.
The primary challenge in moving from a lab-scale prototype to wafer-scale technology lies in the integration of high-quality transition-metal dichalcogenide monolayers. Specifically, achieving uniform, defect-free TMDC films directly grown on silicon nanostructures - or transferring large-area monolayers onto pre-patterned silicon without introducing strain, contamination, or misalignment - remains a key materials and integration hurdle. Addressing this challenge will be critical for realizing scalable, wafer-level quantum photonic devices.
Many quantum optical platforms must balance coherence, brightness, and on-chip routing. Where does your device fall in that tradeoff, and which performance metrics are your next priority for improvement?
At this stage, our device prioritizes robust spin–photon coupling and on-chip integration over ultimate coherence and brightness. The emission we currently detect is primarily incoherent photoluminescence. However, this operating regime allowed us to establish efficient spin control and photon routing in a fully integrated, room-temperature platform.
Our next major performance priority is to achieve deterministic single-photon emission from the heterostructured system. This will involve engineering and positioning quantum emitters within TMDC monolayers to enable coherent, on-demand photon generation. Improving photon indistinguishability, brightness, and coupling efficiency to the silicon nanophotonic resonators will be key milestones toward scalable quantum photonic networks.
What additional components do you see as the most critical to realize a full quantum network built around this kind of room-temperature spin-photon interface?
The most critical additional component is an electro-optic transducer integrated directly with the existing optical device. Such a transducer would enable coherent conversion between electrical and quantum optical signals, allowing spin–photon interfaces to communicate seamlessly with other types of stationary quantum nodes.
In particular, this capability would make it possible to network platforms such as superconducting qubits through optical fiber networks, enabling distributed quantum computing and long-distance quantum communication. Integrating electro-optic transduction with a room-temperature spin–photon interface, therefore, represents a key step toward scalable, heterogeneous quantum networks.
In the near term, what do you think are the most realistic use cases for this technology, and what would a first-generation deployed system actually look like?
In the near term, the most realistic use cases are optical readout of electron spin states and direct discrimination and measurement of photon spin states. Because the device operates at room temperature and is fully compatible with on-chip photonics, it is well-suited for compact quantum sensors and spin-encoded optical receivers.
A first-generation deployed system would likely consist of pixelated on-chip components, with each pixel selectively addressing one of the two opposite photon spin states. Arrays of these pixels could function as integrated spin-resolved detectors or spin-selective optical interfaces, providing a practical and scalable pathway toward more complex quantum networking architectures.
How do you see room-temperature photonic platforms like yours coexisting with, or potentially displacing, today’s cryogenic quantum systems in computing and communication over the next decade?
Over the next decade, room-temperature photonic platforms are likely to coexist with today’s cryogenic quantum systems rather than directly displace them. Cryogenic platforms continue to offer exceptionally high fidelity and well-established scaling pathways, particularly for local quantum processing.
Room-temperature photonic platforms, by contrast, can provide complementary capabilities by enabling low-loss, long-distance interconnection between cryogenic quantum nodes using photons. In this hybrid architecture, photonics serves as the communication backbone, linking high-performance cryogenic processors into distributed quantum networks. Taken together, these approaches combine the strengths of both platforms and offer a realistic path toward scalable quantum computing and communication.
Finally, for students and early-career researchers who are excited by this work, which skills or interdisciplinary areas, do you think will be most important if they want to contribute to next-generation quantum communication devices?
I come from a materials science and engineering background, and I believe that materials quality remains one of the most critical factors in achieving high-performance quantum devices. Reducing impurities and defects, as well as discovering and engineering new materials with tailored quantum properties, will be essential for improving coherence, efficiency, and scalability.
At the same time, heterogeneous integration across materials platforms holds enormous promise for realizing system-level quantum functionalities. Future breakthroughs will increasingly come from researchers who can bridge materials synthesis, nanofabrication, photonics, and quantum device physics. Developing interdisciplinary skills across these areas will be especially important for anyone aiming to contribute to next-generation quantum communication technologies.
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About the Speaker
Feng Pan is a postdoctoral scholar with Prof. Jennifer A. Dionne in the Department of Materials Science and Engineering at Stanford. He received his Ph.D. degree at the University of Wisconsin Madison, advised by Prof. Randall H. Goldsmith. His research expertise spans several aspects, including quantum optics, nanophotonics, metasurfaces, chiral metamaterials, plasmonics, and single-particle microscopy and spectroscopy. He is interested in harnessing photonics to address critical challenges in energy, quantum information science, and sustainability.
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