Compact THz absorption spectroscopy using a LiNbO<sub>3</sub> slot waveguide

Eric R. Sung; Keith A. Nelson

doi:10.1038/s41377-025-02105-4

Your Location：

Home >

Browse articles >

Compact THz absorption spectroscopy using a LiNbO₃ slot waveguide

Original Articles

- Compact THz absorption spectroscopy using a LiNbO₃ slot waveguide
- Compact THz absorption spectroscopy using a LiNbO₃ slot waveguide
- Light: Science & Applications 2026年15卷第2期页码：590-599
- Affiliations：
  
  Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA
- Author bio：
  
  Keith A. Nelson (kanelson@mit.edu)
- Funds：
- DOI：10.1038/s41377-025-02105-4
  中图分类号：
- 收稿：2025-01-15，
  
  修回：2025-09-22，
  
  录用：2025-10-21，
  
  网络首发：2026-01-04，
  
  纸质出版：2026-02-28
- Accepted：
Scan QR Code
Eric R. Sung, Keith A. Nelson. Compact THz absorption spectroscopy using a LiNbO₃ slot waveguide[J]. Light: Science & Applications, 2026,15(2):590-599.

Sung, E. R. & Nelson, K. A. Compact THz absorption spectroscopy using a LiNbO₃ slot waveguide. Light: Science & Applications, 15, 590-599 (2026).
Eric R. Sung, Keith A. Nelson. Compact THz absorption spectroscopy using a LiNbO₃ slot waveguide[J]. Light: Science & Applications, 2026,15(2):590-599. DOI： 10.1038/s41377-025-02105-4.

Sung, E. R. & Nelson, K. A. Compact THz absorption spectroscopy using a LiNbO₃ slot waveguide. Light: Science & Applications, 15, 590-599 (2026). DOI： 10.1038/s41377-025-02105-4.

摘要

Abstract

THz spectroscopy is a powerful tool for studying a variety of samples

ranging from large biomolecules to solid-state materials. In cases where experimental space is limited or sample volumes are small

THz waveguides have been used to enable compact THz spectroscopy. The THz polaritonics platform is a waveguide-based approach that uses a thin lithium niobate slab to allow direct visualization of THz fields as they interact with structures integrated into the waveguide. Although there have been many successful studies using the platform for integrated photonics

the platform’s utility as a spectroscopic tool has been largely unexploited. Here

we use a slot waveguide integrated into the thin lithium niobate slab to measure the absorption spectrum of a sample inserted into the slot. The slot waveguide localizes the THz electric field within a low-index slot where a sample is placed. The THz fields propagate through the slot and are monitored as they interact with the sample. Perturbation theory is then used to extract the absorption spectrum and bulk refractive index of the sample with good sensitivity. These results show much promise for enabling compact linear and nonlinear THz spectroscopy using thin lithium niobate waveguides.

关键词

Keywords

references

Jepsen, P. U., Cooke, D. G. & Koch, M. Terahertz spectroscopy and imaging—modern techniques and applications. Laser Photonics Rev. 5 , 124–166 (2011)..

Koch, M. et al. Terahertz time-domain spectroscopy. Nat. Rev. Methods Prim. 3 , 48 (2023)..

Pickwell, E. & Wallace, V. P. Biomedical applications of terahertz technology. J. Phys. D Appl. Phys. 39 , R301–R310 (2006)..

Fukunaga, K. & Picollo, M. Terahertz spectroscopy applied to the analysis of artists’ materials. Appl. Phys. A 100 , 591–597 (2010)..

Baxter, J. B. & Guglietta, G. W. Terahertz spectroscopy. Anal. Chem. 83 , 4342–4368 (2011)..

Walther, M. et al. Chemical sensing and imaging with pulsed terahertz radiation. Anal. Bioanal. Chem. 397 , 1009–1017 (2010)..

Davies, A. G. et al. Terahertz spectroscopy of explosives and drugs. Mater. Today 11 , 18–26 (2008)..

Hangyo, M., Tani, M. & Nagashima, T. Terahertz time-domain spectroscopy of solids: a review. Int. J. Infrared Millim. Waves 26 , 1661–1690 (2005)..

Smith, R. M. & Arnold, M. A. Terahertz time-domain spectroscopy of solid samples: principles, applications, and challenges. Appl. Spectrosc. Rev. 46 , 636–679 (2011)..

George, D. K. & Markelz, A. G. Terahertz spectroscopy of liquids and biomolecules. in Terahertz Spectroscopy and Imaging (eds Peiponen, K. E., Zeitler, A. & Kuwata-Gonokami, M.) 229–250 (Springer, 2012).

Møller, U. et al. Terahertz reflection spectroscopy of Debye relaxation in polar liquids [invited ] . J. Opt. Soc. Am. B 26 , A113–A125 (2009)..

Pedersen, J. E. & Keiding, S. R. THz time-domain spectroscopy of nonpolar liquids. IEEE J. Quantum Electron. 28 , 2518–2522 (1992)..

Mittleman, D. M. et al. Gas sensing using terahertz time-domain spectroscopy. Appl. Phys. B 67 , 379–390 (1998)..

Lucia, F. C. Spectroscopy in the terahertz spectral region. in Sensing with Terahertz Radiation (ed Mittleman, D.) 39–115 (Springer, 2003).

Chen, Z. et al. Ultrafast multi-cycle terahertz measurements of the electrical conductivity in strongly excited solids. Nat. Commun. 12 , 1638 (2021)..

Ofori-Okai, B. K. et al. DC electrical conductivity measurements of warm dense matter using ultrafast THz radiation. Phys. Plasmas 31 , 042711 (2024)..

Penkov, N. V. Terahertz spectroscopy as a method for investigation of hydration shells of biomolecules. Biophys. Rev. 15 , 833–849 (2023)..

Mancini, T. et al. Terahertz spectroscopic analysis in protein dynamics: current status. Radiation 2 , 100–123 (2022)..

Feurer, T. et al. Terahertz polaritonics. Annu. Rev. Mater. Res. 37 , 317–350 (2007)..

Peier, P. et al. Imaging of THz waves in 2D photonic crystal structures embedded in a slab waveguide. N. J. Phys. 12 , 013014 (2010)..

Ofori-Okai, B. K. et al. Direct experimental visualization of waves and band structure in 2D photonic crystal slabs. N. J. Phys. 16 , 053003 (2014)..

Sivarajah, P. et al. What is the Brillouin zone of an anisotropic photonic crystal? Phys. Rev. B 93 , 054204 (2016)..

Ward, D. W. et al. Coherent control of phonon-polaritons in a terahertz resonator fabricated with femto second laser machining. Opt. Lett. 29 , 2671–2673 (2004)..

Pan, C. P. et al. Direct visualization of light confinement and standing wave in THz Fabry-Perot resonator with Bragg mirrors. Opt. Express 25 , 9768–9777 (2017)..

Sivarajah, P. et al. THz-frequency magnon-phonon-polaritons in the collective strong-coupling regime. J. Appl. Phys. 125 , 213103 (2019)..

Werley, C. A., Nelson, K. A. & Tait, C. R. Direct visualization of terahertz electromagnetic waves in classic experimental geometries. Am. J. Phys. 80 , 72–81 (2012)..

Lai, W. C. et al. On-chip methane sensing by near-IR absorption signatures in a photonic crystal slot waveguide. Opt. Lett. 36 , 984–986 (2011)..

Tombez, L. et al. Methane absorption spectroscopy on a silicon photonic chip. Optica 4 , 1322–1325 (2017)..

Wu, Z. F. et al. Investigation of a slow-light enhanced near-infrared absorption spectroscopic gas sensor, based on hollow-core photonic band-gap fiber. Sensors 18 , 2192 (2018)..

Singh, R. et al. Ultrasensitive terahertz sensing with high- Q Fano resonances in metasurfaces. Appl. Phys. Lett. 105 , 171101 (2014)..

Lee, D. K. et al. Highly sensitive and selective sugar detection by terahertz nano-antennas. Sci. Rep. 5 , 15459 (2015)..

Wang, R. D. et al. Conversion from terahertz-guided waves to surface waves with metasurface. Opt. Express 26 , 31233–31243 (2018)..

Wang, R. D. et al. Enhanced on-chip terahertz sensing with hybrid metasurface/lithium niobate structures. Appl. Phys. Lett. 114 , 121102 (2019)..

Han, B. J. et al. A sensitive and selective terahertz sensor for the fingerprint detection of lactose. Talanta 192 , 1–5 (2019)..

Almeida, V. R. et al. Guiding and confining light in void nanostructure. Opt. Lett. 29 , 1209–1211 (2004)..

Xu, Q. F. et al. Experimental demonstration of guiding and confining light in nanometer-size low-refractive-index material. Opt. Lett. 29 , 1626–1628 (2004)..

Joannopoulos, J. D. et al. Photonic Crystals: Molding the Flow of Light (Princeton University Press, 2008).

Saito, S. et al. First principles calculation of terahertz vibrational modes of a disaccharide monohydrate crystal of lactose. Jpn. J. Appl. Phys. 45 , L1156–L1158 (2006)..

Allis, D. G. et al. Assignment of the lowest-lying THz absorption signatures in biotin and lactose monohydrate by solid-state density functional theory. Chem. Phys. Lett. 440 , 203–209 (2007)..

Peretti, R. et al. THz-TDS time-trace analysis for the extraction of material and metamaterial parameters. IEEE Trans. Terahertz Sci. Technol. 9 , 136–149 (2019)..

Oskooi, A. F. et al. MEEP: a flexible free-software package for electromagnetic simulationsby the FDTD method. Comput. Phys. Commun. 181 , 687–702 (2010)..

Dastrup, B. S. et al. Enhancement of THz generation in LiNbO 3 waveguides via multi-bounce velocity matching. Light Sci. Appl. 11 , 335 (2022)..

Sung, E. R. et al. Enhancement of terahertz fields in LiTaO 3 waveguides using a conical pulse front. Opt. Express 32 , 26913–26924 (2024)..

Cornet, M. et al. Terahertz-field-induced second harmonic generation through Pockels effect in zinc telluride crystal. Opt. Lett. 39 , 5921–5924 (2014)..

Chen, J., Han, P. Y. & Zhang, X. C. Terahertz-field-induced second-harmonic generation in a beta barium borate crystal and its application in terahertz detection. Appl. Phys. Lett. 95 , 011118 (2009)..

Pedersen, T. G. Exciton stark shift and electroabsorption in monolayer transition-metal dichalcogenides. Phys. Rev. B 94 , 125424 (2016)..

Sivarajah, P. et al. Chemically assisted femtosecond laser machining for applications in LiNbO 3 and LiTaO 3 . Appl. Phys. A 112 , 615–622 (2013)..

Wu, Q. et al. Quantitative phase contrast imaging of THz electric fields in a dielectric waveguide. Opt. Express 17 , 9219–9225 (2009)..

浏览量

Downloads

CSCD

文章被引用时，请邮件提醒。

Submit

工具集

关联资源

暂无数据

Compact THz absorption spectroscopy using a LiNbO3 slot waveguide

Compact THz absorption spectroscopy using a LiNbO3 slot waveguide

DOI：10.1038/s41377-025-02105-4

摘要

Abstract

关键词

Keywords

references

Compact THz absorption spectroscopy using a LiNbO₃ slot waveguide

Compact THz absorption spectroscopy using a LiNbO₃ slot waveguide