Publications (25)
Giant conductance of PSS:PEDOT micro-surfaces induced by microbubble lithography
Anand Dev Ranjan, Rakesh Sen, Sumeet Kumar +5
We provide direct evidence of the effects of interface engineering of various substrates by Microbubble lithography (MBL). We choose a model organic plastic (or polymer) poly(3,4-e…
High flux cold Rubidium atomic beam for strongly coupled Cavity QED
Basudev Roy, Michael Scholten
This paper presents a setup capable of producing a high-flux continuous beam of cold rubidium atoms for cavity QED experiments in the regime of strong coupling. A 2 MOT, load…
A label-free sub-diffractive technique for 3D intracellular tomography using thermally induced convection currents
Jayesh Goswami, Shataneek Banerjee, Snigdhadev Chakraborty +8
Conventionally, 3-dimensional cellular tomography can be done with light sheet or multi-angle observations. Recently, a new technique was introduced where the cell was rotated usin…
Micro-OptoMechanical Movements (MOMs) with SoftOxometalates (SOMs): Controlled Motion of Single Soft-Oxometalate Pea-pods Using Exotic Optical Potentials
Basudev Roy, Atharva Sahasrabudhe, Bibudha Parasar +4
An important challenge in the field of materials design and synthesis is to deliberately design mesoscopic objects starting from well-defined precursors and inducing directed movem…
Simultaneous optical trapping and magnetic micromanipulation of ferromagnetic iron-doped upconversion microparticles in six degrees of freedom
Gokul Nalupurackal, Gunaseelan M, Muruga Lokesh +9
Optical trapping of magnetic Fe-oxide particles is notoriously difficult due to their high refractive indices, not to mention high absorptivity at the trapping infra-red wavelength…
In-vivo characterization of optically trapped Brownianprobes at a glance
Rahul Vaippully, Vaibavi Ramanujan, Saumendra Bajpai +1
Calibration of optically trapped particles in-vivo has been complicated given the frequency dependence and spatial inhomogeneity of the cytoplasmic viscosity, and the requirement o…
Simultaneous detection of rotational and translational motion in optical tweezers by measurement of backscattered intensity
Basudev Roy, Sudipta K. Bera, Ayan Banerjee
We describe a simple yet powerful technique of simultaneously measuring both translational and rotational motion of mesoscopic particles in optical tweezers by measuring the backsc…
Pitch-rotational manipulation of single cells and particles using single-beam thermo-optical tweezers
Sumeet Kumar, M. Gunaseelan, Rahul Vaippully +5
3D pitch rotation of microparticles and cells assumes importance in a wide variety of applications in biology, physics, chemistry and medicine. Applications such as cell imaging an…
Controlled transportation of mesoscopic particles by enhanced spin orbit interaction of light in an optical trap
Basudev Roy, Nirmalya Ghosh, Subhasish Dutta Gupta +3
We study the effects of the spin orbit interaction (SOI) of light in an optical trap and show that the propagation of the tightly focused trapping beam in a stratified medium can l…
Probing the dynamics of an optically trapped particle by phase sensitive back focal plane interferometry
Basudev Roy, Sambit Bikas Pal, Arijit Haldar +3
The dynamics of an optically trapped particle are often determined by measuring intensity shifts of the back-scattered light from the particle using position sensitive detectors. W…
Detection of sub-degree fluctuations of the local cellmembrane slope using optical tweezers
Rahul Vaippully, Vaibavi Ramanujan, Manoj Gopalakrishnan +2
Normal thermal fluctuations of the cell membrane have been studied extensively using high resolution microscopy and focused light, particularly at the peripheral regions of a cell.…
Study of adhesivity of surfaces using rotational optical tweezers
Rahul Vaipully, Dhanush Bhatt, Anand Dev Ranjan +1
Optical tweezers are powerful tools for high resolution study of surface properties. Such experiments are traditionally performed by studying the active or the brownian fluctuation…
Roadmap for Optical Tweezers
Giovanni Volpe, Onofrio M. Maragò, Halina Rubinzstein-Dunlop +80
Optical tweezers are tools made of light that enable contactless pushing, trapping, and manipulation of objects ranging from atoms to space light sails. Since the pioneering work b…
NaBiF: Er, Yb upconversion particle as a multi-functional bio-marker
Atanu Ghosh, Krishna Kumari Swain, Agniva Das +6
The paper presents bismuth‑doped NaBiF4:Er³⁺,Yb³⁺ upconversion particles that show markedly higher quantum yield and controllable photoluminescence using two infrared lasers, enabl…
Self assembly of microparticles in stable ring structures in an optical trap
Arijit Haldar, Sambit Bikas Pal, Basudev Roy +2
Micro-particle self assembly under the influence of optical forces produced by higher order optical beams or by projection of a hologram into the trapping volume is well known. In…
Measurement of probe displacement to the thermal resolution limit in photonic force microscopy using a miniature quadrant photodetector
Sambit Bikas Pal, Arijit Haldar, Basudev Roy +1
A photonic force microscope comprises of an optically trapped micro-probe and a position detection system to track the motion of the probe. Signal collection for motion detection i…
Intracellular phagosome shell is rigid enough to transfer outside torque to the inner spherical particle
Srestha Roy, Arvin Gopal Subramaniam, Snigdhadev Chakraborty +6
Intracellular phagosomes have a lipid bilayer encapsulated fluidic shell outside the particle, on the outer side of which, molecular motors are attached. An optically trapped spher…
Controlled and Continuous Patterning of Organic and Inorganic Materials by Induced Nucleation in an Optical Tweezers
Basudev Roy, Manish Arya, Preethi Thomas +5
We demonstrate for the first time controlled patterning by inducing nucleation of material from a dense aqueous dispersion or solution in an optical tweezers. A hot spot is formed…
Self-assembly and complex manipulation of colloidal mesoscopic particles by active thermocapillary stress
Subhrokoli Ghosh, Aritra Biswas, Basudev Roy +1
We demonstrate that the active thermocapillary stresses induced by multiple microbubbles offer simple routes to directed self-assembly and complex but controllable micromanipulatio…
Towards Stirling engine using an optically confined particle subjected to asymmetric temperature profile
Gokul Nalupurackal, Muruga Lokesh, Sarangi Suresh +5
The realization of microscopic heat engines has gained a surge of research interest in statistical physics, soft matter, and biological physics. A typical microscopic heat engine e…
Microscopic approach to understand Brownian dynamics in viscoelastic fluid
Shuvojit Paul, Basudev Roy, Ayan Banerjee
We present an entirely microscopic formulation of viscoleasticity of a fluid starting from the microscopic Stokes-Oldroyd B Model assuming instantaneous hydrodynamic friction, and…
In-vivo femtonewton-sensing nanotribology of Tradescantia zebrina leaf cell inner surface using roll rotation detection
Snigdhadev Chakraborty, Mukul Sagar, Atanu Ghosh +5
Accessing the properties of a plant cell interior non-invasively is difficult due to the presence of a cell wall. Nanoparticles larger than 5 nm cannot be readily phagocytosed insi…
Detection of self-generated nanowaves on the interface of an evaporating sessile water droplet
Dhanush Bhatt, Rahul Vaippully, Bhavesh Kharbanda +4
Evaporating sessile droplets have been known to exhibit oscillations on the air-liquid interface. These are generally over millimeter scales. Using a novel approach, we are able to…
Enhanced topological phase and spin Hall shifts in an optical trap
Basudev Roy, Nirmalya Ghosh, Subhasish Dutta Gupta +2
The spin orbit interaction (SOI) of light has been in the focus in recent times because of fundamental consequences and potential applications in diverse systems ranging from inhom…
Direct verification of the fluctuation-dissipation relation in viscously coupled oscillators
Shuvojit Paul, Abhrajit Laskar, Rajesh Singh +3
The fluctuation-dissipation relation, a central result in non-equilibrium statistical physics, relates equilibrium fluctuations in a system to its linear response to external force…