CKN Research Group - dark brackground

Nanoscale Optical & Cellular Dynamics Lab

The current research of our group focuses on fundamentally understanding the photophysical properties of various fluorescent nanomaterials for their applications in optoelectronics, photonics, quantum technology, and super-resolution bioimaging techniques. Our approach involves tuning these probes for diverse applications, utilizing their unique photophysical properties through both ensemble and single-molecule/particle spectroscopy techniques. We are committed to developing room-temperature single-photon sources to advance quantum computing applications while also uncovering the mechanisms behind single-photon emission. Our investigations have revealed insights into the long-lived emissions of metal nanoclusters, including gold, silver, and copper. We have also established a single-molecule/particle spectroscopy and super-resolution microscopy setup to explore in vitro and in vivo organelle dynamics, encompassing mitochondria, lysosomes, microtubules, endoplasmic reticulum, and chromatin behavior.

Our multidisciplinary team comprises experts in physical, organic, and inorganic chemistry, as well as biology, including cell and plant biology. Together, we utilize advanced spectroscopy (steady-state and time-resolved techniques) and advanced microscopy techniques (FLIM, dSTORM, SRRF) to bring breakthroughs in both fundamental science and practical applications in fields such as quantum technologies, medical diagnostics, targeted therapies, and beyond.

Single Particle Spectroscopy of Nano & Quantum Materials

Single particles often exhibit inconsistent emission behavior, a phenomenon known as blinking or intermittency

Single-particle or molecule spectroscopy is a technique that focuses on studying individual particles or molecules rather than examining a large ensemble of many particles. This approach eliminates the averaging effects found in ensemble measurements (like absorption spectroscopy, fluorescence spectroscopy, and time-resolved spectroscopy techniques), leading to a clearer understanding of the sample. By isolating and studying single particles (molecules), this technique provides deeper insights and highlights the heterogeneity within the sample. In our lab, we have developed a home-built single-particle spectroscopy setup and a fluorescence correlation spectroscopy (FCS) setup used to study the photophysics of quantum and nanomaterials at the single-particle level.

The fluorescence spectroscopic analysis of single particles revealed some exciting phenomena that were previously unknown at the bulk level. Fluorescence blinking or intermittency is one of such phenomena which is unknown at the ensemble level but plays an important role in deciding the fate of the fluorescent material.

Single particles often exhibit inconsistent emission behavior, a phenomenon known as blinking or intermittency

Sci. Rep., 2015, 5 (1), 11423

Single CdTe QDs excited with 488 nm and 532 nm lasers exhibiting excitation-independent single-particle emission statistics

Nanoscale, 2025, 17 (7), 3919-3929

Change in single QDs ON and OFF fraction with increase in Se composition in CdTexSe1-x QDs

J. Phys. Chem. Lett. 2025, 16, 23, 5868–5877

Investigating the photon emission statistics of Gold Nano Clusters using single particle spectroscopy

J. Phys. Chem. Lett. 2020, 11, 14, 5741–5748

Room-Temperature Single Photon Emission

Hanbury-Brown and Twiss (HBT) Setup: Experimental setup to determine the purity of single photon emission

Quantum technologies have the potential to revolutionize various fields, including computing, information processing, sensing, metrology, imaging, cryptography, and communication. These technologies rely on quantum bits, or qubits, which are the quantum analogues of classical bits. Qubits can be implemented using different two-level physical systems, such as superconducting qubits, trapped ion qubits, and photonic qubits. Superconducting qubits use superconducting circuits, trapped ion qubits use atoms or ions, and photonic qubits utilize photons with different colors, phases, or polarizations of photons for qubit generation. Photonic qubits offer several advantages over other types. They can be easily transmitted through optical fibers, are less susceptible to decoherence due to minimal contact with environmental factors, and are a promising candidate for operation at non-zero temperature. In the context of photonic qubits, photons serve as qubits, and single photons are necessary for implementing quantum logic gates and communication protocols.

To realize a photonic qubit, a single photon source is required. A single photon source must generate highly pure single photons on demand with deterministic emission. In our lab, we have utilised colloidal quantum dots to generate single photon with ultra high purity at the room temperature. we are also focused to engineer the single photon emission by various methods involving trap state manipulation via change in core composition

Super Resolution Imaging of Organellar Dynamics

Dynamics of Mitochondria

Dynamics of Lysosomes

Dynamics of Nuclear and Chromatin Reorganisation

Dynamics of the Golgi Apparatus and ER

In vivo C. Elegans as a Model for Organellar Dynamics

Add here

Research on Plant Biology

Single Molecule/Particle Spectroscopy of Nano & Quantum Materials