Research

From measurement to predictive control.

Across laser-induced plasma, droplet dynamics, and multi-MHz OCT, I connect optical-system design, time-resolved measurement, quantitative reconstruction, physical modeling, and uncertainty assessment.

Conceptual visualization of laser delivery, transient flow measurement, and computational modeling. — Schematic overview created for this portfolio; it is not experimental or simulated research data.

Laser energy deposition, plasma evolution, and ignition

Laser energy deposition creates a coupled sequence: optical breakdown, blast-wave formation, plasma cooling, mixing, and, under suitable conditions, ignition. I study that sequence with high-speed Schlieren and spray imaging, absorbed-energy measurements, finite-volume simulations, thermochemistry, and radiation modeling. Producing a breakdown spark is not by itself sufficient for ignition: spatial placement, hot-kernel lifetime, pulse timing, and heat loss determine whether the deposited energy produces a sustained response.

Laser-induced breakdown and plasma-kernel evolution
Single- and double-pulse energy deposition
Atomized fuel-air ignition
High-speed shock-wave tracking
Ph.D. thesis: facility, acquisition, and analysis development

Optical placement diagram and time-resolved shadowgraphs showing laser-driven droplet responses. — Figure source: Predicting and controlling laser-induced breakup and multidirectional propulsion of liquid droplets, PNAS (2026).

Droplet dynamics under vortex, shock-wave, and laser forcing

Short-duration pressure and vorticity impulses can deform, accelerate, and fragment droplets across distinct regimes. My work spans co-axial vortex-droplet interaction, shock-induced aerobreakup, laser-driven fragmentation of droplet arrays, and predictive control of single-droplet propulsion. The current emphasis is to connect calibrated forcing conditions and measured uncertainty with physically interpretable response maps.

Shock-droplet and vortex-droplet interaction
Laser-driven propulsion and fragmentation
High-speed shadowgraphy
Aberration-aware optical modeling
Placement-energy maps and uncertainty propagation

Read the PNAS paper

System diagram and photographs of a dual-resolution multi-MHz OCT rectoscope. — System and probe imagery from the dual-resolution prototype rectoscope study, Journal of Biomedical Optics (2026).

Multi-MHz OCT endoscopy and biomedical optical systems

My biomedical-optics work contributes to multi-megahertz OCT endoscopy through motor-acquisition synchronization, probe design and development, controlled pullback, dual-resolution optics, and image-quality assessment. The published evidence supports prototype instrumentation, model-sample and postmortem tissue imaging, and low-latency visualization; it does not imply demonstrated clinical diagnostic performance.

FDML-based multi-MHz OCT
Fiber and free-space optical design
Probe and optomechanical development
Sensorless rotational synchronization
Image quality, timing, and distortion analysis

Fluid motion on film

High-speed experiments as scientific evidence

Four peer-recorded visual contributions presented through the American Physical Society Division of Fluid Dynamics Gallery of Fluid Motion.

2021APS Gallery of Fluid Motion

Mechanism of shock-induced aerobreakup of a droplet

High-speed shadowgraph and Schlieren visualization of wave interaction, deformation, and the transition between droplet-breakup regimes.

Shubham Sharma, Awanish Pratap Singh, Srinivasa Rao S, Aloke Kumar, Saptarshi Basu

APS record DOI

2020APS Gallery of Fluid Motion

Aerodynamic breakup of droplets in a shock-induced flow

A first-author visual study of shock-wave interaction, airflow-driven deformation, mist stripping, and breakup across Weber-number regimes.

Awanish Pratap Singh, Shubham Sharma, Srinivas Rao, Saptarshi Basu

APS record DOI

2020APS Gallery of Fluid Motion

On the dynamics of vortex droplet co-axial interaction

High-speed PIV, planar laser-induced fluorescence, and shadowgraphy reveal coupled vortex-ring and droplet dynamics.

Shubham Sharma, Awanish Pratap Singh, Saptarshi Basu

APS record DOI

2020APS Gallery of Fluid Motion

Atomization of levitated droplets via laser-induced breakdown

A 50,000-frames-per-second view of nanosecond laser-induced deformation, propulsion, and fragmentation of acoustically levitated droplets.

D. Chaitanya Kumar Rao, Awanish Pratap Singh, Saptarshi Basu

APS record DOI

Videos are embedded from the official APS records. Each work is licensed under CC BY-NC 4.0; author credits and source records are linked above.

Methods

A connected technical toolkit

The exact stack changes with the problem. The standard remains the same: traceable assumptions, quantitative evidence, and reproducible analysis.

Optics

Zemax OpticStudioOCTFDML lasersGaussian beam propagation

Experiment

High-speed imagingSchlierenShadowgraphyPIVPLIF

Computation

C++20PythonMATLABMPIFinite-volume CFD

Engineering

SolidWorks3D printingSensorsMotorsSystem integration

Validation

Uncertainty propagationParameter mapsError analysisBenchmark cases

See the research record

Journal articles and proceedings are maintained separately, with independent numbering and direct links where available.

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