Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Terahertz circular dichroism spectroscopy of biomaterials enabled by kirigami polarization modulators


Terahertz circular dichroism (TCD) offers multifaceted spectroscopic capabilities for understanding the mesoscale chiral architecture and low-energy vibrations of macromolecules in (bio)materials1,2,3,4,5. However, the lack of dynamic polarization modulators comparable to polarization optics for other parts of the electromagnetic spectrum is impeding the proliferation of TCD spectroscopy6,7,8,9,10,11. Here we show that tunable optical elements fabricated from patterned plasmonic sheets with periodic kirigami cuts make possible the polarization modulation of terahertz radiation under application of mechanical strain. A herringbone pattern of microscale metal stripes enables a dynamic range of polarization rotation modulation exceeding 80° over thousands of cycles. Following out-of-plane buckling, the plasmonic stripes function as reconfigurable semi-helices of variable pitch aligned along the terahertz propagation direction. Several biomaterials, exemplified by an elytron of the Chrysina gloriosa, revealed distinct TCD fingerprints associated with the helical substructure in the biocomposite. Analogous kirigami modulators will also enable other applications in terahertz optics, such as polarization-based terahertz imaging, line-of-sight telecommunication, information encryption and space exploration.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Fig. 1: Schematic of chiral kirigami topology.
Fig. 2: THz TDS measurement of a chiral kirigami modulator.
Fig. 3: Understanding the physical meaning of resonance frequency.
Fig. 4: Computed THz circular dichroism and time-averaged current norm distributions on the kirigami modulator with φ = 45°.
Fig. 5: Measurements of TCD using a kirigami chiroptical modulator.

Data availability

All relevant data that support our experimental findings are available from the corresponding author upon reasonable request.


  1. 1.

    Acbas, G., Niessen, K. A., Snell, E. H. & Markelz, A. G. Optical measurements of long-range protein vibrations. Nat. Commun. 5, 3076 (2014).

    Article  Google Scholar 

  2. 2.

    Plusquellic, D. F., Siegrist, K., Heilweil, E. J. & Esenturk, O. Applications of terahertz spectroscopy in biosystems. ChemPhysChem. 8, 2412–2431 (2007).

    CAS  Article  Google Scholar 

  3. 3.

    Wilmink, G. J. & Grundt, J. E. Current state of research on biological effects of terahertz radiation. J. Infrared Milli. Terahz. Waves. 32, 1074–1122 (2011).

    Article  Google Scholar 

  4. 4.

    Choi, J. H. & Cho, M. Terahertz chiroptical spectroscopy of an α-helical polypeptide: a molecular dynamics simulation study. J. Phys. Chem. B. 118, 12837–12843 (2014).

    CAS  Article  Google Scholar 

  5. 5.

    King, M. D., Buchanan, W. D. & Korter, T. M. Understanding the terahertz spectra of crystalline pharmaceuticals: terahertz spectroscopy and solid-state density functional theory study of (S)-(+)-ibuprofen and (RS)-ibuprofen. J. Pharm. Sci. 100, 1116–1129 (2011).

    CAS  Article  Google Scholar 

  6. 6.

    Kan, T. et al. Enantiomeric switching of chiral metamaterial for terahertz polarization modulation employing vertically deformable MEMS spirals. Nat. Commun. 6, 8422 (2015).

    CAS  Article  Google Scholar 

  7. 7.

    Cong, L., Pitchappa, P., Wang, N. & Singh, R. Electrically programmable chiral MEMS photonics. Preprint at (2018).

  8. 8.

    Zhang, S. et al. Photoinduced handedness switching in terahertz chiral metamolecules. Nat. Commun. 3, 942 (2012).

    Article  Google Scholar 

  9. 9.

    Oh, S. S. & Hess, O. Chiral metamaterials: enhancement and control of optical activity and circular dichroism. Nano Converg. 2, 24 (2015).

    Article  Google Scholar 

  10. 10.

    Qui, J. et al. Introducing quasi-optical terahertz circular dichroism spectroscopy. Proc. 2017 11th Int. Conf. Antenna Theory Tech. ICATT 11, 26–29 (2017).

    Article  Google Scholar 

  11. 11.

    Dhillon, S. S. et al. The 2017 terahertz science and technology roadmap. J. Phys. D 50, 043001 (2017).

    Article  Google Scholar 

  12. 12.

    Yen, T. J. et al. Terahertz magnetic response from artificial materials. Science 303, 1494–1496 (2004).

    CAS  Article  Google Scholar 

  13. 13.

    Grady, N. K. et al. Terahertz metamaterials for linear polarization conversion and anomalous refraction. Science 340, 1304–1307 (2013).

    CAS  Article  Google Scholar 

  14. 14.

    Hunsche, S., Koch, M., Brener, I. & Nuss, M. THz near-field imaging. Opt. Commun. 150, 22–26 (1998).

    CAS  Article  Google Scholar 

  15. 15.

    Chan, W. L., Deibel, J. & Mittleman, D. M. Imaging with terahertz radiation. Rep. Prog. Phys. 70, 1325–1379 (2007).

    Article  Google Scholar 

  16. 16.

    Xu, L. et al. Kirigami nanocomposites as wide-angle diffraction gratings. ACS Nano 10, 6156–6162 (2016).

    CAS  Article  Google Scholar 

  17. 17.

    Blees, M. K. et al. Graphene kirigami. Nature 524, 204–207 (2015).

    CAS  Article  Google Scholar 

  18. 18.

    Rafsanjani, A. et al. Buckling-induced kirigami. Phys. Rev. Lett 118, 084301 (2017).

    Article  Google Scholar 

  19. 19.

    Liu, Z. et al. Nano-kirigami with giant optical chirality. Sci. Adv. 4, eaat4436 (2018).

    Article  Google Scholar 

  20. 20.

    Callens, S. J. P. & Zadpoor, A. A. From flat sheets to curved geometries: origami and kirigami approaches. Mater. Today 21, 241–264 (2018).

    Article  Google Scholar 

  21. 21.

    Zhang, Y. et al. A mechanically driven form of kirigami as a route to 3D mesostructures in micro/nanomembranes. Proc. Natl Acad. Sci. U.SA 112, 11757–11764 (2015).

    CAS  Article  Google Scholar 

  22. 22.

    Liu, X. et al. Metamaterials on parylene thin film substrates: design, fabrication, and characterization at terahertz frequency. Appl. Phys. Lett. 96, 011906 (2010).

    Article  Google Scholar 

  23. 23.

    Mislow, K. Molecular Chirality, in Topics in Sterochemistry Vol. 22 (Topics in Stereochemistry, Wiley, 1999).

  24. 24.

    Gansel, J. K. et al. Gold helix photonic metamaterial as broadband circular polarizer. Science 325, 1513–1515 (2009).

    CAS  Article  Google Scholar 

  25. 25.

    Wang, Z. et al. Origami-based reconfigurable metamaterials for tunable chirality. Adv. Mater. 29, 1700412 (2017).

    Article  Google Scholar 

  26. 26.

    Jinh, L. et al. Kirigami metamaterials for reconfigurable toroidal circular dichroism. NPG Asia Mater. 10, 888–898 (2018).

    Article  Google Scholar 

  27. 27.

    Neu, J., Aschaffenburg, D. J., Williams, M. R. C. & Schmuttenmaer, C. A. Optimization of terahertz metamaterials for near-field sensing of chiral substances. IEEE Trans. Terahertz Sci. Technol. 7, 755–764 (2017).

    CAS  Article  Google Scholar 

  28. 28.

    Tranter, G. E. in Encyclopedia of Spectroscopy and Spectrometry 2nd edn (ed. Lindon, J. C.) 325–336 (Academic Press, 2010).

  29. 29.

    Sharma, V., Crne, M., Park, J. O. & Srinivasarao, M. Structural origin of circularly polarized iridescence in jeweled beetles. Science 325, 449–451 (2009).

    CAS  Article  Google Scholar 

  30. 30.

    Weaver, J. C. et al. The stomatopod dactyl club: a formidable damage-tolerant biological hammer. Science 336, 1275–1280 (2012).

    CAS  Article  Google Scholar 

Download references


All the authors acknowledge support from the Defense Advanced Research Projects Agency (DARPA) project HR00111720067 ‘Electromagnetic Processes and Normal Modes in Bacterial Biofilms’. Parts of the work were also supported by the NSF projects ‘Energy- and Cost-Efficient Manufacturing Employing Nanoparticles’ (NSF 1463474) and ‘Multi-Scale Origami For Novel Photonics’ (NSF 071702). The authors also acknowledge financial and programmatic support from the University of Michigan College of Engineering’s Blue Sky Initiative, the UM Electron Microscopy Facility (MC)2 for its assistance with electron microscopy and NSF grant no. DMR-9871177 for funding of the JEOL 2010F analytical electron microscope used in this work. We acknowledge the Lurie Nanofabrication Facility for facilitating the fabrication of kirigami modulators.

Author information




W.J.C., G.C., T.B.N. and N.A.K. contributed to the design, data analysis and preparation of the manuscript. N.A.K. originated the concept. W.J.C. designed and fabricated the kirigami modulators and measured the mechanical responses. W.J.C. and G.C. performed the optical experiments and W.J.C., G.C. and Z.H. performed the simulations. S.Z. provided technical support for reconstruction of the 3D kirigami model. W.J.C., G.C., T.B.N. and N.A.K. planned and supervised the project.

Corresponding authors

Correspondence to Theodore B. Norris or Nicholas A. Kotov.

Ethics declarations

Competing interests

The authors declare no competing interests.

Additional information

Publisher’s note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary information

Supplementary Information

Supplementary methods, Supplementary Figs. 1–28, Supplementary video captions 1–2, Supplementary references 1–40

Supplementary Video 1

Video of stretching and release of kirigami chiroptical modulator (ε from 0 to 22.5%)

Supplementary Video 2

Video of the 3D topology of a reconstructed kirigami structure with 45° wire slant angle stretched by 13.5% strain

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Choi, W.J., Cheng, G., Huang, Z. et al. Terahertz circular dichroism spectroscopy of biomaterials enabled by kirigami polarization modulators. Nat. Mater. 18, 820–826 (2019).

Download citation

Further reading


Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing