Varun Dolia

All Publications

• Very-large-scale integrated high quality factor nanoantenna pixels. Nature nanotechnology Dolia, V., Balch, H. B., Dagli, S., Abdollahramezani, S., Carr Delgado, H., Moradifar, P., Chang, K., Stiber, A., Safir, F., Lawrence, M., Hu, J., Dionne, J. A. 2024

  Abstract

  Metasurfaces precisely control the amplitude, polarization and phase of light, with applications spanning imaging, sensing, modulation and computing. Three crucial performance metrics of metasurfaces and their constituent resonators are the quality factor (Q factor), mode volume (Vm) and ability to control far-field radiation. Often, resonators face a trade-off between these parameters: a reduction in Vm leads to an equivalent reduction in Q, albeit with more control over radiation. Here we demonstrate that this perceived compromise is not inevitable: high quality factor, subwavelength Vm and controlled dipole-like radiation can be achieved simultaneously. We design high quality factor, very-large-scale-integrated silicon nanoantenna pixels (VINPix) that combine guided mode resonance waveguides with photonic crystal cavities. With optimized nanoantennas, we achieve Q factors exceeding 1,500 with Vm less than 0.1 ( λ / n air ) 3 . Each nanoantenna is individually addressable by free-space light and exhibits dipole-like scattering to the far-field. Resonator densities exceeding a million nanoantennas per cm2 can be achieved. As a proof-of-concept application, we show spectrometer-free, spatially localized, refractive-index sensing, and fabrication of an 8 mm × 8 mm VINPix array. Our platform provides a foundation for compact, densely multiplexed devices such as spatial light modulators, computational spectrometers and in situ environmental sensors.

  View details for DOI 10.1038/s41565-024-01697-z

  View details for PubMedID 38961248

  View details for PubMedCentralID 10971570

• Rapid genetic screening with high quality factor metasurfaces. Nature communications Hu, J., Safir, F., Chang, K., Dagli, S., Balch, H. B., Abendroth, J. M., Dixon, J., Moradifar, P., Dolia, V., Sahoo, M. K., Pinsky, B. A., Jeffrey, S. S., Lawrence, M., Dionne, J. A. 2023; 14 (1): 4486

  Abstract

  Genetic analysis methods are foundational to advancing personalized medicine, accelerating disease diagnostics, and monitoring the health of organisms and ecosystems. Current nucleic acid technologies such as polymerase chain reaction (PCR) and next-generation sequencing (NGS) rely on sample amplification and can suffer from inhibition. Here, we introduce a label-free genetic screening platform based on high quality (high-Q) factor silicon nanoantennas functionalized with nucleic acid fragments. Each high-Q nanoantenna exhibits average resonant quality factors of 2,200 in physiological buffer. We quantitatively detect two gene fragments, SARS-CoV-2 envelope (E) and open reading frame 1b (ORF1b), with high-specificity via DNA hybridization. We also demonstrate femtomolar sensitivity in buffer and nanomolar sensitivity in spiked nasopharyngeal eluates within 5 minutes. Nanoantennas are patterned at densities of 160,000 devices per cm2, enabling future work on highly-multiplexed detection. Combined with advances in complex sample processing, our work provides a foundation for rapid, compact, and amplification-free molecular assays.

  View details for DOI 10.1038/s41467-023-39721-w

  View details for PubMedID 37495593

  View details for PubMedCentralID PMC10372074

• Rapid genetic screening with high quality factor metasurfaces. ArXiv Hu, J., Safir, F., Chang, K., Dagli, S., Balch, H. B., Abendroth, J. M., Dixon, J., Moradifar, P., Dolia, V., Sahoo, M. K., Pinsky, B. A., Jeffrey, S. S., Lawrence, M., Dionne, J. A. 2021

  Abstract

  Genetic analysis methods are foundational to advancing personalized and preventative medicine, accelerating disease diagnostics, and monitoring the health of organisms and ecosystems. Current nucleic acid technologies such as polymerase chain reaction (PCR), next-generation sequencing (NGS), and DNA microarrays rely on fluorescence and absorbance, necessitating sample amplification or replication and leading to increased processing time and cost. Here, we introduce a label-free genetic screening platform based on high quality (high-Q) factor silicon nanoantennas functionalized with monolayers of nucleic acid fragments. Each nanoantenna exhibits substantial electromagnetic field enhancements with sufficiently localized fields to ensure isolation from neighboring resonators, enabling dense biosensor integration. We quantitatively detect complementary target sequences using DNA hybridization simultaneously for arrays of sensing elements patterned at densities of 160,000 pixels per cm$^2$. In physiological buffer, our nanoantennas exhibit average resonant quality factors of 2,200, allowing detection of two gene fragments, SARS-CoV-2 envelope (E) and open reading frame 1b (ORF1b), down to femtomolar concentrations. We also demonstrate high specificity sensing in clinical nasopharyngeal eluates within 5 minutes of sample introduction. Combined with advances in biomarker isolation from complex samples (e.g., mucus, blood, wastewater), our work provides a foundation for rapid, compact, amplification-free and high throughput multiplexed genetic screening assays spanning medical diagnostics to environmental monitoring.

  View details for PubMedID 34671699

  View details for PubMedCentralID PMC8528080

• Progress, Challenges, and Opportunities in the Synthesis, Characterization, and Application of Metal-Boride-Derived Two-Dimensional Nanostructures ACS MATERIALS LETTERS Gunda, H., Klebanoff, L. E., Sharma, P., Varma, A. K., Dolia, V., Jasuja, K., Stavila, V. 2021; 3 (5): 535-556

  View details for DOI 10.1021/acsmaterialslett.1c00086

  View details for Web of Science ID 000648431100008

• Dissimilar adsorption of higher-order aggregates compared with monomers and dimers of methylene blue on graphene oxide: An optical spectroscopic perspective Carbon Trends Dolia, V., James, A. L., Chakrabarty, S., Jasuja, K. 2021; 4

  View details for DOI 10.1016/j.cartre.2021.100066