• Characterization of a waveguide Mach-Zehnder interferometer using PDMS as a cover layer 

      Lindecrantz, Susan Mariah; Tinguely, Jean-Claude; Ahluwalia, Balpreet Singh; Hellesø, Olav Gaute (Journal article; Tidsskriftartikkel; Peer reviewed, 2015)
      A Mach-Zehnder interferometer made with shallow rib waveguides is studied experimentally and using simulations. The rib-height giving single-mode guidance is found as function of core thickness and polarization. Devices have been made using shallow rib waveguides (5 nm rib height) in silicon nitride. The sensitivity and the limit of detection (LOD) is studied experimentally regarding the length of ...
    • Chip-based multimodal super-resolution microscopy for histological investigations of cryopreserved tissue sections 

      Villegas, Luis; Dubey, Vishesh Kumar; Nystad, Mona; Tinguely, Jean-Claude; Coucheron, David Andre; Dullo, Firehun Tsige; Priyadarshi, Anish; Acuna Maldonado, Sebastian Andres; Ahmad, Azeem; Mateos, Jose M.; Barmettler, Gery; Ziegler, Urs; Birgisdottir, Åsa Birna; Hovd, Aud-Malin Karlsson; Fenton, Kristin Andreassen; Acharya, Ganesh; Agarwal, Krishna; Ahluwalia, Balpreet Singh (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-02-24)
      Histology involves the observation of structural features in tissues using a microscope. While diffraction-limited optical microscopes are commonly used in histological investigations, their resolving capabilities are insufficient to visualize details at subcellular level. Although a novel set of super-resolution optical microscopy techniques can fulfill the resolution demands in such cases, the ...
    • Fluorescence fluctuation-based super-resolution microscopy using multimodal waveguided illumination 

      Opstad, Ida Sundvor; Hansen, Daniel Henry; Acuña Maldonado, Sebastian Andres; Ströhl, Florian; Priyadarshi, Anish; Tinguely, Jean-Claude; Dullo, Firehun Tsige; Dalmo, Roy Ambli; Seternes, Tore; Ahluwalia, Balpreet Singh; Agarwal, Krishna (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-07-19)
      Photonic chip-based total internal reflection fluorescence microscopy (c-TIRFM) is an emerging technology enabling a large TIRF excitation area decoupled from the detection objective. Additionally, due to the inherent multimodal nature of wide waveguides, it is a convenient platform for introducing temporal fluctuations in the illumination pattern. The fluorescence fluctuation-based nanoscopy technique ...
    • High spatially sensitive quantitative phase imaging assisted with deep neural network for classification of human spermatozoa under stressed condition 

      Butola, Ankit; Popova, Daria; Prasad, Dilip K.; Ahmad, Azeem; Habib, Anowarul; Tinguely, Jean-Claude; Basnet, Purusotam; Acharya, Ganesh; Paramasivam, Senthilkumaran; Mehta, Dalip Singh; Ahluwalia, Balpreet Singh (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-08-04)
      Sperm cell motility and morphology observed under the bright field microscopy are the only criteria for selecting a particular sperm cell during Intracytoplasmic Sperm Injection (ICSI) procedure of Assisted Reproductive Technology (ART). Several factors such as oxidative stress, cryopreservation, heat, smoking and alcohol consumption, are negatively associated with the quality of sperm cell and ...
    • High-Throughput Total Internal Reflection Fluorescence and Direct Stochastic Optical Reconstruction Microscopy Using a Photonic Chip 

      Coucheron, David Andre; Helle, Øystein Ivar; Øie, Cristina Ionica; Tinguely, Jean-Claude; Ahluwalia, Balpreet Singh (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-11-16)
      Total internal reflection fluorescence (TIRF) is commonly used in single molecule localization based super-resolution microscopy as it gives enhanced contrast due to optical sectioning. The conventional approach is to use high numerical aperture microscope TIRF objectives for both excitation and collection, severely limiting the field of view and throughput. We present a novel approach to generating ...
    • Improving the space-bandwidth product of structured illumination microscopy using a transillumination configuration 

      Joseph, Joby; Faiz, Kandankulangara P.; Lahrberg, Marcel; Tinguely, Jean-Claude; Ahluwalia, Balpreet Singh (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-11-18)
      Applying structured instead of plane illumination in widefield optical fluorescence microscopy can improve the spatial resolution beyond what is known as the Abbe limit. In general it is not only the resolution of an imaging system that is of interest but also its field of view (FOV). These two parameters are expressed in the space-bandwidth product (SBP). Here we introduce a modified structured ...
    • Label-free nanoscopy enabled by coherent imaging with photonic waveguides 

      Ströhl, Florian; Opstad, Ida Sundvor; Tinguely, Jean-Claude; Dullo, Firehun Tsige; Kaminski, Clemens F.; Ahluwalia, Balpreet Singh (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-07-29)
      In this project it was found that Fourier ptychographic microscopy can be improved far beyond its conventional limits via waveguide-based optical systems. Extensive in silico studies showed that images obtained on highrefractive index material waveguide chips in conjunction with hyperspectral illumination light and finely designed waveguide geometries can be combined via a modified phase-retrieval ...
    • Multimodal on-chip nanoscopy and quantitative phase imaging reveals the nanoscale morphology of liver sinusoidal endothelial cells 

      Butola, Ankit; Coucheron, David Andre; Szafranska, Karolina; Ahmad, Azeem; Mao, Hong; Tinguely, Jean-Claude; McCourt, Peter Anthony; Paramasivam, Senthilkumaran; Mehta, Dalip Singh; Agarwal, Krishna; Ahluwalia, Balpreet Singh (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-11-23)
      Visualization of three-dimensional (3D) morphological changes in the subcellular structures of a biological specimen is a major challenge in life science. Here, we present an integrated chip-based optical nanoscopy combined with quantitative phase microscopy (QPM) to obtain 3D morphology of liver sinusoidal endothelial cells (LSEC). LSEC have unique morphology with small nanopores (50-300 nm in ...
    • Photonic-chip assisted correlative light and electron microscopy 

      Tinguely, Jean-Claude; Steyer, Anna Maria; Øie, Cristina Ionica; Helle, Øystein Ivar; Dullo, Firehun Tsige; Olsen, Randi; McCourt, Peter; Schwab, Yannick; Ahluwalia, Balpreet Singh (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-12-07)
      Correlative light and electron microscopy (CLEM) unifies the versatility of light microscopy (LM) with the high resolution of electron microscopy (EM), allowing one to zoom into the complex organization of cells. Here, we introduce photonic chip assisted CLEM, enabling multi-modal total internal reflection fluorescence (TIRF) microscopy over large field of view and high precision localization of the ...
    • Photonic-chip: a multimodal imaging tool for histopathology 

      Villegas, Luis; Dubey, Vishesh Kumar; Tinguely, Jean-Claude; Coucheron, David Andre; Priyadarshi, Anish; Acuña Maldonado, Sebastian Andres; Agarwal, Krishna; Mateos, Jose M; Nystad, Mona; Hovd, Aud-Malin Karlsson; Fenton, Kristin Andreassen; Ahluwalia, Balpreet Singh (Conference object; Konferansebidrag, 2021-04)
      We propose the photonic-chip as a multimodal imaging platform for histopathological assessment, allowing large fields-of-view across diverse microscopy methods including total internal reflection fluorescence and single-molecule localization.
    • Quantitative phase microscopy of red blood cells during planar trapping and propulsion 

      Ahmad, Azeem; Dubey, Vishesh; Singh, Vijay; Tinguely, Jean-Claude; Øie, Cristina Ionica; Wolfson, Deanna; Mehta, Dalip Singh; So, Peter T. C.; Ahluwalia, Balpreet Singh (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-08-22)
      Red blood cells (RBCs) have the ability to undergo morphological deformations during microcirculation, such as changes in surface area, volume and sphericity. Optical waveguide trapping is suitable for trapping, propelling and deforming large cell populations along the length of the waveguide. Bright field microscopy employed with waveguide trapping does not provide quantitative information about ...
    • Silicon nitride waveguide platform for fluorescence microscopy of living cells 

      Tinguely, Jean-Claude; Helle, Øystein Ivar; Ahluwalia, Balpreet Singh (Journal article; Tidsskriftartikkel; Peer reviewed, 2017)
      Waveguide chip-based microscopy reduces the complexity of total internal reflection fluorescence (TIRF) microscopy, and adds features like large field of view illumination, decoupling of illumination and collection path and easy multimodal imaging. However, for the technique to become widespread there is a need of low-loss and affordable waveguides made of high-refractive index material. Here, ...
    • Single-mode limit and bending losses for shallow Rib Si3N4 waveguides 

      Dullo, Firehun Tsige; Tinguely, Jean-Claude; Solbø, Stian; Hellesø, Olav Gaute (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-01-07)
      The single-mode limit and bending losses for shallow rib waveguides are studied using the full vectorial film mode matching method. The maximum rib height for single-mode waveguides is found to be on the order of 10 nm for a rib width of 2 m and a wavelength of 785 nm, with the exact value depending on the core thickness and the polarization. Bending losses are calculated as a function of several ...
    • Structured illumination microscopy using a photonic chip 

      Helle, Øystein Ivar; Dullo, Firehun Tsige; Lahrberg, Marcel; Tinguely, Jean-Claude; Hellesø, Olav Gaute; Ahluwalia, Balpreet Singh (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-04-11)
      Structured illumination microscopy (SIM) enables live-cell super-resolution imaging of subcellular structures at high speeds. At present, linear SIM uses free-space optics to illuminate the sample with the desired light patterns; however, such arrangements are prone to misalignment and add cost and complexity to the microscope. Here, we present an alternative photonic chip-based two-dimensional SIM ...
    • Sub-nanometer height sensitivity by phase shifting interference microscopy under environmental fluctuations 

      Ahmad, Azeem; Dubey, Vishesh Kumar; Butola, Ankit; Tinguely, Jean-Claude; Ahluwalia, Balpreet Singh; Mehta, Dalip Singh (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-03-18)
      Phase shifting interferometric (PSI) techniques are among the most sensitive phase measurement methods. Owing to its high sensitivity, any minute phase change caused due to environmental instability results into, inaccurate phase measurement. Consequently, a well calibrated piezo electric transducer (PZT) and highly-stable environment is mandatory for measuring accurate phase map using PSI implementation. ...
    • Super-condenser enables labelfree nanoscopy 

      Ströhl, Florian; Opstad, Ida Sundvor; Tinguely, Jean-Claude; Dullo, Firehun Tsige; Mela, Ioanna; Osterrieth, Johannes W.M; Ahluwalia, Balpreet Singh; Kaminski, Clemens F. (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-08-22)
      Labelfree nanoscopy encompasses optical imaging with resolution in the 100 nm range using visible wavelengths. Here, we present a labelfree nanoscopy method that combines coherent imaging techniques with waveguide microscopy to realize a <i>super-condenser</i> featuring maximally inclined coherent darkfield illumination with artificially stretched wave vectors due to large refractive indices of the ...
    • Super-condenser enables labelfree nanoscopy 

      Ströhl, Florian; Opstad, Ida Sundvor; Tinguely, Jean-Claude; Dullo, Firehun Tsige; Mela, Ioanna; Osterrieth, Johannes W.M; Ahluwalia, Balpreet Singh; Kaminski, Clemens F. (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-08-22)
      Labelfree nanoscopy encompasses optical imaging with resolution in the 100 nm range using visible wavelengths. Here, we present a labelfree nanoscopy method that combines coherent imaging techniques with waveguide microscopy to realize a <i>super-condenser</i> featuring maximally inclined coherent darkfield illumination with artificially stretched wave vectors due to large refractive indices of the ...
    • Transmission structured illumination microscopy with tunable frequency illumination using tilt mirror assembly 

      Samanta, Krishnendu; Ahmad, Azeem; Tinguely, Jean-Claude; Ahluwalia, Balpreet Singh; Joseph, Joby (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-01-26)
      We present experimental demonstration of tilt-mirror assisted transmission structured illumination microscopy (tSIM) that offers a large field of view super resolution imaging. An assembly of custom-designed tilt-mirrors are employed as the illumination module where the sample is excited with the interference of two beams reflected from the opposite pair of mirror facets. Tunable frequency structured ...
    • 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 ...
    • A waveguide imaging platform for live-cell TIRF imaging of neurons over large fields of view 

      Opstad, Ida Sundvor; Ströhl, Florian; Fantham, Marcus J.; Hockings, Colin; Vanderpoorten, Oliver; Tartwijk, Francesca W. van; Qiaojin Lin, Julie; Tinguely, Jean-Claude; Dullo, Firehun Tsige; Kaminski‐Schierle, Gabriele S.; Ahluwalia, Balpreet Singh; Kaminski, Clemens F. (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-02-17)
      Large fields of view (FOVs) in total internal reflection fluorescence microscopy (TIRFM) via waveguides have been shown to be highly beneficial for single molecule localisation microscopy on fixed cells [1,2] and have also been demonstrated for short‐term live‐imaging of robust cell types [3‐5], but not yet for delicate primary neurons nor over extended periods of time. Here, we present a waveguide‐based ...