This phase-matching method unlocks both efficient THz generation from femtosecond optical pulses and sensitive THz detection on the same chip.
From chip to free space
Many real-world applications require THz signals to radiate into free space. To bridge this gap, our team integrated planar antennas directly onto the lithium niobate chip. These antennas couple the broadband THz pulses out of the chip and into the open, which enables compatibility with imaging, spectroscopy, and wireless communication setups. Borrowing principles from conventional radio-frequency (RF) design, we tuned antenna and transmission line geometries to target specific frequency bands—and it offers the community a new level of control over THz output.
Lithium niobate advantages
To evaluate performance, the team compared our device to commercial photoconductive antennas—the current standard choice for THz generation and detection.
When measuring under the same conditions, we found that our chips already deliver comparable performance. There is plenty of room for optimization, so we believe lithium niobate can soon surpass the state of the art by orders of magnitude.
Lithium niobate brings several intrinsic advantages that make it uniquely suited for THz applications:
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No bias voltage is required for THz generation—and it enables large-scale integration without complex drive electronics.
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High-power handling—the material tolerates watt-level optical inputs, with on-chip intensities millions of times higher than those in fiber or free space. This may enable high-power THz applications without room-sized lasers.
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On-chip modulation—our team demonstrated that THz radiation modulates light, which opens the door to compact terahertz modulators.
Lithium niobate photonic circuits are already fueling applications for 6G communications, quantum technologies, and even optical computing. With this new demonstration, the material’s reach now extends into the terahertz frontier.
Since our method is fully compatible with existing photonic circuits, we hope to enable terahertz operation across the same applications—and open entirely new ones.
Our research was supported by the European Union (MIRAQLS Grant No. 101070700), the Swiss National Science Foundation (PRIMA Grant No. 201547), and the SNSF-NSF Lead Agency program (NSF ECCS-2407727).
FURTHER READING
Y. Lampert et al., Nat. Commun., 16, 7004 (2025); https://doi.org/10.1038/s41467-025-62267-y.