Functionalized diamond optomechanical circuits for infrared spectroscopy and site-specific gas sensing applications
Optics, Quantum Optics and Physics of Atoms, Molecules and Plasmas
Final Report Abstract
In this project, we elucidated the potentials and capabilities of integrated photonic diamond circuits for sensing. This work was driven by the capacity of integrated circuits to confine strong optical fields on a sub-wavelength scale, which causes a very sensitive response of the guided modes to any changes in the waveguide surrounding. This motivated the development of circuits on several material platforms with the prospect of implementing evanescent-wave coupling schemes covering a huge spectral range from the visible to the LWIR regime. Here, especially diamond was studied as a device material for infrared wavelength. The structures were fabricated from PCD layers grown by CVD on wafer-scale substrates. Diamond-oninsulator was used as a platform in the NIR regime (with a propagation loss of 4.3dB/mm) where the surface functionalization of waveguides for the detection of AFP as an indicator for a certain kind of cancer was studied. This paves the way for implementing integrated photonic sensing of proteins via click-chemistry binding to the waveguide surface for life-science applications. Towards this, novel click-chemistry approaches for dip-pen nanolithography and related microspotting techniques were developed to allow targeted functionalization of specific devices and areas on a devices. First diamond circuits for device operation in the LWIR regime were based on diamond-on-AlN structures. It could be shown that the large waveguide attenuation of these devices was caused by the nitride buffer properties. A further development of the diamond platform led to suspended circuits, which enabled device operation in the visible, NIR and LWIR regime on a single sample. For these circuits an attenuation of 8.9dB/mm and a ring resonator quality factor up to 6200 in the NIR regime as well as an attenuation of 9.8dB/mm in the LWIR regime at a wavelength of 8 µm was achieved. Coupling to and from the circuits was not only demonstrated via the waveguide end facet but also via grating couplers for out-of-plane access. This platform enables the development of so far unattainable sensing schemes by combining measurements in the visible, NIR and LWIR regime with the prospect of being expandable even to the far-IR region. Besides its application for spectroscopic measurements in the fingerprint region, the presented diamond platform is a promising candidate for the miniaturization of general optical systems in the LWIR regime, which offers a major growth opportunity for integrated photonic technologies.
Publications
- “Diamond on aluminum nitride as a platform for integrated photonic circuits,” Phys. status solidi A 2016, 213, 2075-2080
N. Gruhler, T. Yoshikawa, P. Rath, G. Lewes-Malandrakis, E. Schmidhammer, C. Nebel, W. H. P. Pernice
(See online at https://doi.org/10.1002/pssa.201600227) - “A Comparative Study of Thiol-Terminated Surface Modification by Click Reactions: Thiol-yne Coupling versus Thiol-ene Michael Addition” Adv. Mater. Interfaces 2018, 5, 1801343
S. M. M. Dadfar, S. Sekula-Neuner, V. Trouillet, M. Hirtz
(See online at https://doi.org/10.1002/admi.201801343) - “Diamond as a Platform for Integrated Quantum Photonics” Adv. Quantum Technol. 2018, 1, 1800061
F. Lenzini, N. Gruhler, N. Walter, W. H. P. Pernice
(See online at https://doi.org/10.1002/qute.201800061) - “Near-Field Coupling in Hybrid Integrated Photonic Circuits”, PhD Thesis, University of Münster, 2018
N. Gruhler
- “Site-Specific Surface Functionalization via Microchannel Cantilever Spotting (µCS): Comparison between Azide-Alkyne and Thiol-Alkyne Click Chemistry Reactions” Small 2018, 14, 1800131
S. M. M. Dadfar, S. Sekula-Neuner, U. Bog, V. Trouillet, M. Hirtz
(See online at https://doi.org/10.1002/smll.201800131) - “Coupling Chemistry for Surface Immobilization in Scanning Probe Lithography”, PhD Thesis, Karlsruher Institut für Technologie (KIT), 2019
S. M. M. Dadfar
(See online at https://doi.org/10.5445/IR/1000097307) - “Evaluation of click chemistry microarrays for immunosensing of alphafetoprotein (AFP)” Beilstein J. Nanotechnol. 2019, 10, 2505-2515
S. M. M. Dadfar, S. Sekula-Neuner, V. Trouillet, H. Liu, R. Kumar, A. K. Powell, M. Hirtz
(See online at https://doi.org/10.3762/bjnano.10.241)
