• Chip-Based Resonance Raman Spectroscopy Using Tantalum Pentoxide Waveguides 

      Coucheron, David Andre; Wadduwage, Dushan Nawoda; Murugan, Ganapathy Senthil; So, Peter T. C.; Ahluwalia, Balpreet Singh (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-05-08)
      Blood analysis is an important diagnostic tool, as it provides a wealth of information about the patient's health. Raman spectroscopy is a promising tool for blood analysis, but widespread clinical application is limited by its low signal strength, as well as complex and costly instrumentation. The growing field of waveguide-based Raman spectroscopy tries to solve these challenges by working toward ...
    • Extraordinary evanescent field confinement waveguide sensor for mid-infrared trace gas spectroscopy 

      Vlk, Marek; Datta, Anurup; Alberti, Sebastian; Yallew, Henock Demessie; Mittal, Vinita; Murugan, Ganapathy Senthil; Jágerská, Jana (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-01-29)
      Nanophotonic waveguides are at the core of a great variety of optical sensors. These structures confine light along defined paths on photonic chips and provide light–matter interaction via an evanescent field. However, waveguides still lag behind free-space optics for sensitivity-critical applications such as trace gas detection. Short optical pathlengths, low interaction strengths, and spurious ...
    • Free-standing tantalum pentoxide waveguides for gas sensing in the mid-infrared 

      Vlk, Marek; Datta, Anurup; Alberti, Sebastian; Murugan, Ganapathy Senthil; Aksnes, Astrid; Jagerska, Jana (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-08-23)
      Typical applications of integrated photonics in the mid-infrared (MIR) are different from near-infrared (telecom) range and, in many instances, they involve chemical sensing through MIR spectroscopy. Such applications necessitate tailored designs of optical waveguides. Both cross-sectional designs and processing methods of MIR waveguides have been a subject of extensive research, where material ...
    • Study of waveguide background at visible wavelengths for on-chip nanoscopy 

      Coucheron, David Andre; Helle, Øystein I.; Wilkinson, James S.; Murugan, Ganapathy Senthil; Domínguez, Carlos; Angelskår, Hallvard; Ahluwalia, Balpreet S. (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-06-17)
      On-chip super-resolution optical microscopy is an emerging field relying on waveguide excitation with visible light. Here, we investigate two commonly used high-refractive index waveguide platforms, tantalum pentoxide (Ta<sub>2</sub>O<sub>5</sub>) and silicon nitride (Si<sub>3</sub>N<sub>4</sub>), with respect to their background with excitation in the range 488–640 nm. The background strength from ...
    • A transparent waveguide chip for versatile total internal reflection fluorescence-based microscopy and nanoscopy 

      Priyadarshi, Anish; Wolfson, Deanna; Ahmad, Azeem; Jayakumar, Nikhil; Dubey, Vishesh Kumar; Tinguely, Jean-Claude; Ahluwalia, Balpreet Singh; Murugan, Ganapathy Senthil (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-08-20)
      Total internal reflection fluorescence (TIRF) microscopy is an imaging technique that, in comparison to confocal microscopy, does not require a trade-off between resolution, speed, and photodamage. Here, we introduce a waveguide platform for chip-based TIRF imaging based on a transparent substrate, which is fully compatible with sample handling and imaging procedures commonly used with a standard ...