Welcome to Santosh Kumar's webpage
About Me
I’ve had a passion for science and research since I was a child, and my intensive studying and hard work finally paid off in 2013 when I graduated and became a qualified Researcher. I enjoy delving into new fields of research and following the results of my experiments into the uncharted scientific territory. Learn more about my work by checking out my current projects and past publications.
Research Interest:
Specializes in the research areas of
• Theoretical and experimental Atomic, Molecular, and Optical Physics,
• Microwave Technologies and Electric-Field Sensing,
• Nonlinear Optics and Quantum Optics,
• Quantum Information and Secure Quantum Communication.
Academic Record
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Present Status: Research Assistant Professor at Stevens Institute of Technology, New Jersey, USA, (April 2024- ).
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Senior Research Scientist at Stevens Institute of Technology, New Jersey, USA, (Dec 2021- March 2024).
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Research Scientist at Stevens Institute of Technology, New Jersey, USA, (Feb 2019- Oct 2021).
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Post-doctoral Fellow at Stevens Institute of Technology, New Jersey, USA, (March 2017- January 2019).
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Supervisor: Dr. Yuping Huang
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Postdoc Experience: Post-doctoral Fellow at The University of Oklahoma, Norman, Oklahoma, USA, (14 June 2013 - 05 March 2017).
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Postdoc Supervisor: Prof. James P. Shaffer
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Visiting Scholar: CNRS Laboratoire Aim ́e Cotton, Universit ́e Paris Sud 11, Campus d’Orsay, France, May-June 2010, June-July 2011 and June-July 2012 (6-months). Collaborator:Prof. Fabien Bretenaker
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Ph.D. Thesis title: Coherent Optical Manipulation and Processing via Dark States in Multi-level Atomic Systems, ( 08 Aug 2007- 14 May 2013).
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Ph.D. Advisor: Prof. Rupamanjari Ghosh,
Experimental Skills
• Handling of Laser systems, operation & stabilization, cavity-locking, and data acquisition.
• Handling of optical instruments and expertise in optical component mounting techniques.
• Knowledge of basics electronics equipment.
• Building and debugging of electronic circuits.
• Designing quantum optics experiments.
• Working experience on cold atoms-cavity experiments.
• Working experience in Optical Parametric Oscillator.
• Parametric down conversion, Single photon time-correlated coincidence measurements.
• Handling of vacuum pumps: turbo and ion pumps, a field-programmable gate array (FPGA),
Pixel fly cameras etc.
Computer Skills
• Languages known: Mathematica, Matlab, Python, LabView
• LateX, Origin, Spice-5, high frequency structural simulator (HFFS)
• Parallel Programming and Cluster Computing
• Working experience with word-processors on Windows/Linux/Mac
My Research
Research involves constant investigating and redesigning of the scientific questions posed. The strength of my research lies in the breadth and depth of the experimental, computational and statistical approaches I utilize in understanding the mechanisms that drive the systems I am studying. Learn more about my ongoing research projects below.
Electromagnetically Induced Transparency and Light Storage
I have carried out extensive experimental and theoretical explorations of the role of atomic coherence for the realization of phenomena, such as Electromagnetically Induced Transparency (EIT) and slow light, with possible application in magnetometer and magneto-optic switch and the role of population oscillation in the realization of ultra-narrow resonance that cannot be attributed to EIT, which is known as Coherent Population Oscillation (CPO). I have also studied this new phenomenon for different polarizations of coupling and probe beams in a multi-level atomic system. We have shown that this long-lived CPO can be used as a light-storing device. We believe that this new phenomenon, insensitive to the inhomogeneous magnetic field, might also be useful for the photon pair generation and parametric amplification.
Scalable quantum network
A scalable quantum network is one of the most desired goals for quantum-information processing. A quantum network consists of nodes which are connected by communication channels. The nodes contain qubits and allow for storage and local processing of quantum information. The communication channels are used to transfer quantum states as well as to create quantum entanglement among nodes. We consider a network whose nodes are high-finesse electromagnetic cavities, each coupled to a single atom or ensemble of atoms which has multiple levels for quantum processing. The cavities are connected by optical fibers. Each atom or ensemble of atoms can be addressed by a control laser.
Research: Atom-Based Electric field Sensing
We have shown for the first time that Rydberg atom based Electromagnetically Induced Transparency (EIT) can be used to sense and image Microwave (MW) electric field with unprecedented precision. The current sensitivity limit is ∼ 3 μV/(cm Hz^1/2). Our method utilizes EIT with Rydberg atoms in room temperature vapor cells to read out the effect that the MW electric field has on the Rydberg atoms.
Research: Cavity Rydberg-EIT
We have shown cavity-assisted Rydberg-atom electromagnetically induced transparency (EIT) using a high-finesse optical cavity (F∼28000). Rydberg atoms are excited via a two-photon transition in a ladder-type EIT configuration. A three-peak structure of the cavity transmission spectrum is observed when Rydberg EIT is generated inside the cavity. The two symmetrically spaced side peaks are caused by bright-state polaritons, while the central peak corresponds to a dark-state polariton. Anticrossing phenomena and the effects of mirror adsorbate electric fields are studied under different experimental conditions. We determine a lower bound on the coherence time for the system of 7.26±0.06μs, most likely limited by laser dephasing. The cavity-Rydberg EIT system can be useful for single-photon generation using the Rydberg blockade effect, studying many-body physics, and generating novel quantum states among many other applications.
Research: Mode Selective Image Up-Conversion
We study selective upconversion of optical signals according to their detailed transverse electromagnetic modes, and demonstrate its proof of operations in a nonlinear crystal. The mode selectivity is achieved by preparing the pump wave in an optimized spatial profile to drive the upconversion. For signals in the Laguerre-Gaussian modes, we show that a mode can be converted with up to 60 times higher efficiency than an overlapping but orthogonal mode. This nonlinear-optical approach may find applications in compressive imaging, pattern recognition, quantum communications, and others where the existing linear-optical methods are limited.
Research: Quantum Airy Photons
With exotic propagation properties, optical Airy beams have been well studied for innovative applications in communications, biomedical imaging, micromachining, and so on. Here we extend those studies to the quantum domain, creating quantum correlated photons in finite-energy Airy transverse modes via spontaneous parametric down conversion and subsequential spatial light modulation. Through two-photon coincidence measurements, we verify their Airy spatial wavefunctions, propagation along a parabolic trajectory, and that the spatial modulation does not introduce any observable degradation of quantum correlation between the photons. These results suggest the feasibility of using spatially structured photons for practically advantageous quantum applications.
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