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Raman spectroscopy on a siliconnitride waveguide platform

Research Area: Photonic integrated circuits for the visible/near IR , Silicon photonics for lab-on-chip spectroscopy

Main Researcher: Ashim Dhakal

Raman spectroscopy provides spectrum of the vibrational energy of the chemical bonds of the molecules and therefore provides an accurate means for identification of the molecules or their concentration. However, Raman signal is very weak due to its very small scattering cross section. On the one hand, owing to enhancement of the field near the waveguides, and long interaction length, Raman signal can be enhanced significantly using waveguides. On the other hand, the waveguides can be structured to form cavities for further enhancement. Thus, photonic waveguides provide an excellent means for efficient, cost-effective and small form-factor Raman spectroscopy. We use silicon-nitride (Si3N4) based waveguides and other integrated photonic elements such as ring resonators, DBRs, etc fabricated using advanced CMOS processing techniques for on-chip Raman spectroscopy on the analyte placed in the close proximity to the waveguides.

Other people involved:

Related Research Projects

PhD thesises



    International Journals

  1. Z. Liu, J. Zhang, G. Roelkens, N. Le Thomas, R. Baets, Bottom-reflector enhanced grating couplers micro-transfer printed on silicon nitride photonic integrated circuits, accepted for publication in Journal of Lightwave Technology,  (to be published).
  2. D. Khalenkow, A. Diaz Tormo, A. De Meyst, L. Van Der Meeren, J. Verduijn, J. Rybarczyk, D. Vanrompay, N. Le Thomas, A. G Skirtach, Chlamydia psittaci infected cell studies by 4Pi Raman and atomic force microscopy, Microscopy, dfae011, p.1-9 doi:10.1093/jmicro/dfae011 (2024).
  3. Z. Liu, H. Zhao, B. Baumgartner, B. Lendl, A. Stassen, A. Skirtach, N. Le Thomas, R. Baets, Ultra-sensitive slot-waveguide-enhanced Raman spectroscopy for aqueous solutions of non-polar compounds using a functionalized silicon nitride photonic integrated circuit, Optics Letters, 46(5), p.1153 doi:10.1364/OL.416464 (2021)  Download this Publication (2.1MB).
  4. Y. Li, H. Zhao, A. Raza, S. Clemmen, R. Baets, Surface-enhanced Raman spectroscopy based on plasmonic slot waveguides with free-space oblique illumination, Journal of Quantum Electronics, 56(1), p.paper 7200108 (8 pages) doi:10.1109/jqe.2019.2946839 (2020)  Download this Publication (3.1MB).
  5. H. Zhao, B. Baumgartner, A. Raza, A. Skirtach, B. Lendl, R. Baets, Multiplex volatile organic compound Raman sensing with nanophotonic slot waveguides functionalized with a mesoporous enrichment layer, Optics Letters, 45(2), p.447-450 doi:10.1364/OL.379469 (2020)  Download this Publication (821KB).
  6. J. Losada, A. Raza, S. Clemmen, A. Serrano, A. Griol, R. Baets, A. Martinez, SERS detection via individual bow-tie nanoantenna integrated in SiN waveguides, IEEE Journal on Selected Topics in Quantum Electronics, doi:10.1109/jstqe.2019.2896200 (2019).
  7. A. Raza, S. Clemmen, P.C. Wuytens, M. Muneeb, M. V. Daele, J. Dendooven, C. Detavernier, A. Skirtach, R. Baets, ALD assisted nanoplasmonic slot waveguide for on-chip Enhanced Raman Spectroscopy, Applied Physics Letters - Photonics, 3(11), p.116105 (12 pages) doi:10.1063/1.5048266 (2018)  Download this Publication (1.2MB).
  8. F. Peyskens, P.C. Wuytens, A. Raza, P. Van Dorpe, R. Baets, Waveguide excitation and collection of surface-enhanced Raman scattering from a single plasmonic antenna, Nanophotonics, 7(7), p.1299–1306 doi:10.1515/nanoph-2018-0003 (2018)  Download this Publication (1.1MB).
  9. N. Le Thomas, A. Dhakal, A. Raza, F. Peyskens, R. Baets, Impact of fundamental thermodynamic fluctuations on light propagating in photonic waveguides made of amorphous materials, Optica, 5(4), p.328-336 doi:10.1364/OPTICA.5.000328 (2018)  Download this Publication (1.1MB).
  10. H. Zhao, S. Clemmen, A. Raza, R. Baets, Stimulated Raman spectroscopy of analytes evanescently probed by a silicon nitride photonic integrated waveguide, Optics Letters, 43(6), p.1403-1406 doi:10.1364/OL.43.001403 (2018)  Download this Publication (1.5MB).
  11. A. Dhakal, P.C. Wuytens, A. Raza, N. Le Thomas, R. Baets, Silicon Nitride Background in Nanophotonic Waveguide Enhanced Raman Spectroscopy, Materials, 10(140), doi:10.3390/ma10020140 (2017)  Download this Publication (1.6MB).
  12. A. Dhakal, P.C. Wuytens, F. Peyskens, K. Jans, N. Le Thomas, R. Baets, Nanophotonic waveguide enhanced Raman spectroscopy of biological submonolayers, ACS Photonics, 3(12), p.2141-2149 doi:10.1021/acsphotonics.6b00593 (2016).
  13. F. Peyskens, A. Dhakal, P. Van Dorpe, N. Le Thomas, R. Baets, Surface Enhanced Raman Spectroscopy Using a Single Mode Nanophotonic-Plasmonic Platform, ACS Photonics, 3(1), p.102-108 doi:10.1021/acsphotonics.5b00487 (2016).
  14. A. Subramanian, E.M.P. Ryckeboer, A. Dhakal, F. Peyskens, A. Malik, B. Kuyken, H. Zhao, S. Pathak, A. Ruocco, A. De Groote, P.C. Wuytens, D. Martens, F. Leo, W. Xie, U.D. Dave, M. Muneeb, Pol Van Dorpe, J. Van Campenhout, W. Bogaerts, P. Bienstman, N. Le Thomas, D. Van Thourhout, Zeger Hens, G. Roelkens, R. Baets, Silicon and silicon nitride photonic circuits for spectroscopic sensing on-a-chip , Photonics Research (invited), 5(3), p.B47 doi:10.1364/PRJ.3.000B47 (2015)  Download this Publication (1.5MB).
  15. A. Dhakal, A. Subramanian, P.C. Wuytens, F. Peyskens, N. Le Thomas, R. Baets, Evanescent excitation and collection of spontaneous Raman spectra using silicon nitride nanophotonic waveguides, Optics Letters, 39(13), p.4025-4028 doi:10.1364/ol.39.004025 (2014).
      International Conferences

    1. Z. Liu, N. Le Thomas, R. Baets, On-chip silicon nitride, optical phased array as a broadband near-infrared spectrometer, SPIE Photonics West: Integrated Optics: Devices, Materials, and Technologies XXVII, United States, (2023)  Download this Publication (9.1MB).
    2. N. Le Thomas, Z. Liu, C. Lin, H. Zhao, R. Baets, Raman on-chip: Current status and future tracks, Proc. SPIE, Integrated Optics: Devices, Materials, and Technology XXV (invited), 11689, p.1168908 doi:10.1117/12.2579222 (2021)  Download this Publication (809KB).
    3. N. Turk, A. Raza, P.C. Wuytens, H. Demol, M. van Daele, C. Detavernier, A. Skirtach, K. Gevaert, R. Baets, Waveguide-based Detection of Protease Activity using Surface-Enhanced Raman Spectroscopy, Frontiers in Optics, United States, (2020).
    4. N. Turk, H. Demol, A. Skirtach, R. Baets, K. Gevaert, Towards SERS-based multiplexed monitoring of protease activity using non-natural aromatic amino acids, EOS Annual Meeting 2020, Portugal, (2020).
    5. Z. Liu, H. Zhao, B. Baumgartner, B. Lendl, A. Skirtach, N. Le Thomas, R. Baets, Ultra-sensitive silicon nitride waveguide-enhanced Raman spectroscopy for aqueous solutions of organic compounds, Conference on Lasers and Electro-Optics (CLEO), p.paper SF2N.6 (2 pages) (2020)  Download this Publication (719KB).
    6. Michiel Van Daele, Matthew BE Griffiths, A. Raza, Matthias M Minjauw, Eduardo Solano, Ji-Yu Feng, Ranjith K Ramachandran, S. Clemmen, R. Baets, Seán T Barry, Christophe Detavernier, Jolien Dendooven, Near Room Temperature PE-ALD of Nanostructured Gold for Enhanced Raman Scattering, ECS Meeting Abstracts, MA2019-02, doi:10.1149/ma2019-02/24/1156 (2019).
    7. N. Le Thomas, Fundamental sensing limits of integrated nanophotonic sensors, Latin America Optics & Photonics Conference (OSA - LAOP 2018) (invited), Peru, p.paper Tu2A.1 (2 pages) (2018)  Download this Publication (2MB).
    8. A. Raza, S. Clemmen, M. de Goede, R. Ali, P. Hua, S. M. Garcia-Blanco, S. Honkanen, J. S. Wilkinson, R. Baets, The performance of High-Index-Contrast Photonics Platforms for On-Chip Raman Spectroscopy, European Conference on Integrated Optics (ECIO, Spain, p.35-37 (2018)  Download this Publication (195KB).
    9. H. Zhao, S. Clemmen, A. Raza, R. Baets, Demonstration of Stimulated Raman Scattering on a Silicon Nitride Photonic Integrated Waveguide, Conference on Lasers and Electro-Optics (CLEO 2018), United States, doi:10.1364/CLEO_SI.2018.SM1B.3 (2018)  Download this Publication (2.1MB).
    10. E.M.P. Ryckeboer, D. Martens, H. D'heer, P. Bienstman, D. Van Thourhout, R. Baets, Optofluidic devices based on Silicon photonics, EOS World of Photonics Congress (invited), (2017).
    11. P.C. Wuytens, A.G. Skirtach, R. Baets, Nanotriangle Decorated Silicon Nitride Waveguides for Integrated Surface-Enhanced Raman Spectroscopy, CLEO: Science and Innovations 2017, STh1M(8), United States, doi:10.1364/cleo_si.2017.sth1m.8 (2017)  Download this Publication (392KB).
    12. A. Raza, P.C. Wuytens, F. Peyskens, S. Clemmen, P. V. Dorpe, R. Baets, On-chip Enhanced Raman spectroscopy using metal slot waveguide, European Conference on Integrated Optics (ECIO), 19(T7.4), Netherlands, (2017).
    13. S. Clemmen, A. Raza, A. Dhakal, F. Peyskens, A. Subramanian, P, Van Dorpe, P.C. Wuytens, H. Zhao, E.M.P. Ryckeboer, S. Severi, N. Le Thomas, R. Baets, Spectroscopic sensing with silicon nitride photonic integrated circuits, Photonics West 2017, Proc. SPIE 10106, Integrated Optics: Devices, Materials, and Technologies XXI (invited), United States, p.101060T doi:10.1117/12.2256526 (2017)  Download this Publication (1.6MB).
    14. R. Baets, Brillouin and Raman scattering in silicon and silicon nitride photonic integrated circuits, 17th International Conference Laser Optics 2016 (invited), Russia, (2016).
    15. S. Clemmen, H. Zhao, F. Peyskens, A. Dhakal, P.C. Wuytens, A. Subramanian, N. Le Thomas, R. Baets, Coherent anti-Stokes Raman spectroscopy on chip, 28th IEEE Photonics Conference (IPC 2015), United States, p.623-624 doi:10.1016/b978-0-12-710404-1.50007-3 (2015)  Download this Publication (169KB).
    16. A. Dhakal, F. Peyskens, A. Subramanian, N. Le Thomas, R. Baets, Enhanced Spontaneous Raman Signal Collected Evanescently by Silicon Nitride Slot Waveguides, CLEO: 2015 - Laser Science to Photonic Applications, United States, p.paper STh4H.3 doi:10.1364/cleo_si.2015.sth4h.3 (2015).
    17. P.C. Wuytens, A. M. Yashchenok, A. Subramanian, R. Baets, A. G. Skirtach, Label-free monitoring of microcapsule-enabled intracellular release using gold-nanoparticle coated microchips , International Conference on Raman Spectroscopy, Germany, p.Mop-HS4-1 (2014).
    18. P.C. Wuytens, A. M. Yashchenok, A. Subramanian, R. Baets, A.G. Skirtach, Label-free monitoring of microcapsule-enabled intracellular release using goldnanoparticle coated microchips, Surface Enhanced Spectroscopies 2014, Germany, p.158 (2014)  Download this Publication (1.4MB).
        National Conferences

      1. P.C. Wuytens, A. Raza, H. Zhao, N. Turk, F. Peyskens, X. Nie, A. Dhakal, E.M.P. Ryckeboer, S. Clemmen, N. Le Thomas, R. Baets, On-chip Raman Spectroscopy, FEA Research Syposium 2017, Belgium, (2017)  Download this Publication (5MB).

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