Flat Optical Devices
Conventional optical elements have curved surfaces that necessitate light beam to be centered on the geometrical center of the optical elements (along with normal incidence) to avoid undue beam deflections, and thereby, avoid beam misalignment and distortions. In compact and portable optical devices, misalignment of the order of a few micrometers can cause significant operational issues. This strict dependency on beam alignment can be removed by designing optical elements with flat surfaces. We are working on design and experimental demonstration of flat optical devices operating in visible and infrared wavelengths.
Determining the transfer function of a reconstructive spectrometer using measurements at two wavelengths, Optics Letters, 48(14), 3753-3756 (2023).
Reconstructive Spectrometer using Photonic Crystal Cavity, Optics Express, 29, 17, 26645-26657 (2021).
Translationally Invariant Generation of Annular Beams using Thin Films, IEEE Photonics Technology Letters, 32, 1273-1276 (2020).
Quantum Technologies
Quantum dots, also known as artificial atoms, are semiconductor nanocrystals that are promising building blocks for quantum communication and quantum computing technologies. We work on engineering electromagnetic environment of quantum dots to design and develop on-chip optoelectronic devices that operate in the quantum realm. We are also working on engineering hybrid optomechanical systems for application in quantum metrology and sensing.
Multi-parameter Optimization for Ground-state Cooling of Mechanical Mode using Quantum Dots, arXiv:2104.14533 [quant-ph] (2021).
Polarons Explain Luminescence Behavior of Colloidal Quantum Dots at Low Temperature, Scientific Reports, 8: 8385 (2018).
Overcoming Auger recombination in nanocrystal quantum dot laser using spontaneous emission enhancement, Optics Express, 22: 3013-3027 (2014).
Spontaneous emission enhancement and saturable absorption of colloidal quantum dots coupled to photonic crystal cavity, Optics Express, 21: 29612-29619 (2013).
Non-invasive Optical Imaging Techniques
Surface and volume imaging without altering or disturbing the object under investigation is critical in semiconductor device development and medical diagnostics. We are working on developing optical techniques that enable imaging over large areas in a non-invasive manner.
Diffraction Imaging of Cracks in Self-assembled Photonic Crystals, Optical Materials, 91: 189-194 (2019).
Flexible Photonic and Optoelectronic Devices
Mechanical flexibility of photonic devices enables broadband tunability of optical functionality and conformity with curved surfaces for wearable devices. Typically, flexible devices utilize a polymer substrate that enables large-area, high-throughput, and cost-efficient fabrication of devices. We are working on design and experimental demonstration of flexible photonic and optoelectronic devices for sensing applications.
Optical gratings fabricated using the capillary-assisted self-assembly of nanoparticles on a flexible substrate, Applied Optics, 62 (21), 5786-5793 (2023).
Funding Support: Science and Engineering Research Board (SERB), Department of Science and Technology (DST), Indo-French Centre for the Promotion of Advanced Research (IFCPAR/CEFIPRA)