Terahertz photonics on-chip

Ileana-Cristina Benea-Chelmus

Hybrid Photonics Laboratory, EPFL, Switzerland

Integrated photonics is becoming increasingly appealing to miniaturize and custom-tailor terahertz sources and detectors[1]. They provide ways to custom-tailor the geometry of waveguides and with it, the dispersion, routing, and confinement of both optical and terahertz signal on-chip. These benefits can be exploited to increase the sensitivity [2,3], the signal-to-noise ratio or the spectral selectivity of such devices [4,5], bringing advantages over bulk crystals.

In this talk, I will discuss our recent efforts to develop hybrid optical-terahertz circuits from two different material platforms, hybrid silicon-organic, and thin film lithium niobate. I will show how structures such as terahertz waveguides and cavities can be explored together with optical waveguides to increase the efficiency of nonlinear mixing between telecom beams and terahertz waves and, hence, realize more power-efficient terahertz devices.

Figure 1: Co-integrated terahertz and optical waveguides used for broadband terahertz generation from a miniaturized chip.

References

[1] S. Rajabali and I.-C. Benea-Chelmus. “Present and future of terahertz integrated photonic devices.”, APL Photonics, 8(8):080901 (2023)
[2] Y. Salamin et al., “Compact and ultra-efficient broadband plasmonic terahertz field detector,” Nat. Commun. 10(1) 1–8 (2019), doi: 10.1038/s41467-019-13490-x
[3] I.-C. Benea-Chelmus et al., “Electro-optic interface for ultrasensitive intracavity electric field measurements at microwave and terahertz frequencies,” Optica 7(5) 498-505 (2020), doi: 10.1364/OPTICA.384160
[4] A. Herter et al., “Terahertz waveform synthesis in integrated thin-film lithium niobate platform,” Nat. Commun. 14(1), 1–9 (2023), doi: 10.1038/s41467-022-35517-6
[5] A. Tomasino, A. Shams-Ansari, M. Lončar, and I.-C. Benea-Chelmus. “500 GHz field-resolved detection in thin-film lithium niobate devices.” In “2023 48th International Conference on Infrared, Millimeter and Terahertz Waves (IRMMW-THz),” pages 1–2 (2023)