Education / Work History
- Ph.D. Scholar, IIT Kanpur (2015-present)
- M.Sc., Aligarh Muslim University, (2014)
- B.Sc., Aligarh Muslim University, (2012)
Research Topic / Interest
Email me here to know more about my work or ask me to update this. My interest is mainly in thermal lens spectroscopy.
Publications
These will include only those published in our lab.
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Diluting Convective Effects in Femtosecond Laser Induced Thermal Lens Measurements with Thermally Active Constituents.
S. Chakraborty, A. K. Mishra, A. K. Rawat, and D. Goswami, in Frontiers in Optics + Laser Science 2022 (FIO, LS) (2022), Paper JW5A.25 (Optica Publishing Group, 2022), p. JW5A.25
[Abstract]
[PDF]
[BibTeX]
Abstract: We report Thermal Lens measurements on the binary liquid mixtures of Methanol and Phenol with femtosecond pulse excitations. The photothermal response is found to be strongly dependent on relative concentrations and the constituents’ molecular properties.
BibTeX: @inproceedings{chakrabortyDilutingConvectiveEffects2022, title = {Diluting {{Convective Effects}} in {{Femtosecond Laser Induced Thermal Lens Measurements}} with {{Thermally Active Constituents}}}, booktitle = {Frontiers in {{Optics}} + {{Laser Science}} 2022 ({{FIO}}, {{LS}}) (2022), Paper {{JW5A}}.25}, author = {Chakraborty, Subhajit and Mishra, Amit Kumar and Rawat, Ashwini Kumar and Goswami, Debabrata}, date = {2022-10-17}, pages = {JW5A.25}, publisher = {{Optica Publishing Group}}, url = {https://opg.optica.org/abstract.cfm?uri=FiO-2022-JW5A.25}, urldate = {2022-12-31}, eventtitle = {Frontiers in {{Optics}}} } -
Quality Assessment of the Commercially Available Alcohol-Based Hand Sanitizers with Femtosecond Thermal Lens Spectroscopy.
S. Chakraborty, A. K. Rawat, A. K. Mishra, and D. Goswami, PeerJ Analytical Chemistry 5, e25 (2023)
[Abstract]
[PDF]
[BibTeX]
Abstract: Using femtosecond-pulse-induced thermal lens spectroscopy (FTLS), we report a novel method for the quality measurements of alcohol-based hand sanitizers (ABHS). To sustain its effectiveness, the ABHS must contain the recommended concentration of alcohol content. We diluted the hand sanitizer with water to reduce the quantity of alcohol in the mixture and then performed thermal measurements on it. We performed both dual-beam Z-scan and time-resolved TL measurements to identify the alcoholic content in the ABHS. The thermal lens (TL) signal of the solvent is capable of detecting any relative change in the alcohol content in the mixture. Our technique, therefore, emerges as a sensitive tool for quality testing of alcohol-based hand sanitizers.
BibTeX: @article{chakrabortyQualityAssessmentCommercially2023, title = {Quality Assessment of the Commercially Available Alcohol-Based Hand Sanitizers with Femtosecond Thermal Lens Spectroscopy}, author = {Chakraborty, Subhajit and Rawat, Ashwini Kumar and Mishra, Amit Kumar and Goswami, Debabrata}, date = {2023-05-30}, journaltitle = {PeerJ Analytical Chemistry}, shortjournal = {PeerJ An. Chem.}, volume = {5}, pages = {e25}, publisher = {{PeerJ Inc.}}, issn = {2691-6630}, doi = {10.7717/peerj-achem.25}, url = {https://peerj.com/articles/achem-25}, urldate = {2023-07-28} } -
Sensing the Molecular Properties in Methanol and Its Binary Mixtures Using Time-Resolved Thermal Lens Spectrometer.
S. Chakraborty, A. K. Rawat, and D. Goswami, in 2019 Workshop on Recent Advances in Photonics (WRAP) (2019), pp. 1–3
[Abstract]
[BibTeX]
Abstract: Mode Mismatched Pump-Probe spectroscopic method was employed to examine the thermally induced nonlinear optical properties of methanol and its binary mixtures. The heat transfer mechanism in methanol and its binary mixtures with carbon tetrachloride (CCl4) at different concentrations of methanol is investigated. Methanol has the highest Thermal Lens (TL) signal, and CCl4 does not have any TL signal at all. However, the presence of CCl4 modulates the TL signal of the binary mixture. The time-domain shift in TL signal is observed for different concentrations of methanol, which indicates the unusual molecular behavior in the binary mixture.
BibTeX: @inproceedings{chakrabortySensingMolecularProperties2019, title = {Sensing the {{Molecular Properties}} in {{Methanol}} and Its {{Binary Mixtures}} Using {{Time-Resolved Thermal Lens Spectrometer}}}, booktitle = {2019 {{Workshop}} on {{Recent Advances}} in {{Photonics}} ({{WRAP}})}, author = {Chakraborty, Subhajit and Rawat, Ashwini Kumar and Goswami, Debabrata}, date = {2019-12}, pages = {1--3}, issn = {null}, doi = {10.1109/WRAP47485.2019.9013697}, eventtitle = {2019 {{Workshop}} on {{Recent Advances}} in {{Photonics}} ({{WRAP}})} } -
Understanding the Photothermal Response of CBNP Nanofluids Using Thermal Lens Spectroscopic Techniques.
S. Chakraborty, A. K. Mishra, A. K. Rawat, and D. Goswami, in Frontiers in Optics + Laser Science 2021 (2021), Paper JTu1A.99 (Optica Publishing Group, 2021), p. JTu1A.99
[Abstract]
[PDF]
[BibTeX]
Abstract: We performed a dual beam Z-Scan experiment to examine the thermal lensing effects in CBNP nanofluids. The photothermal characteristics and heat dissipation dynamics were observed for these nanofluids at different levels of their linear absorption.
BibTeX: @inproceedings{chakrabortyUnderstandingPhotothermalResponse2021, title = {Understanding the {{Photothermal Response}} of {{CBNP Nanofluids Using Thermal Lens Spectroscopic Techniques}}}, booktitle = {Frontiers in {{Optics}} + {{Laser Science}} 2021 (2021), Paper {{JTu1A}}.99}, author = {Chakraborty, Subhajit and Mishra, Amit Kumar and Rawat, Ashwini Kumar and Goswami, Debabrata}, date = {2021-11-01}, pages = {JTu1A.99}, publisher = {{Optica Publishing Group}}, doi = {10.1364/FIO.2021.JTu1A.99}, url = {https://opg.optica.org/abstract.cfm?uri=LS-2021-JTu1A.99}, urldate = {2022-12-31}, eventtitle = {Laser {{Science}}} } -
Two-Photon-Induced Fluorescence Study of Rhodamine-6G Dye in Different Sets of Binary Solvents.
R. K. Gupta, S. Kant, A. K. Rawat, and D. Goswami, Journal of Fluorescence (2020)
[Abstract]
[PDF]
[BibTeX]
Abstract: This study deals with the effects of different sets of binary solvents on the Two-Photon Induced Fluorescence (TPIF), a non-linear process, of the Rhodamine-6G (Rh6G) dye, which is a well-known xanthene dye. This work examines the importance of inter-molecular interactions, which results in the modulation of the TPIF of the Rh6G. In this work, we have investigated three binary solvent mixtures representing varying polarity and intermolecular interactions. Specific solvent mixtures used are methanol-water, methanol-dimethyl formamide, and methanol-chloroform. Since the solvent polarity across these binary solvents differs, there are significant intermolecular interactions in the binary mixture solvents, which modulate the two-photon process of Rh6G when irradiated with high-intensity laser light at 780 nm. In our studies, we find that Rh6G in the MeOH-H2O binary solvent has maximum red-shift and minimum intensity as compared to other pairs of binary liquids when the volume fraction of methanol decreases due to more extensive hydrogen bonding between the two components. Additionally, at 1:1 ratio of binary mixtures, Rh6G is found to have the highest TPEACS value for methanol-chloroform binary solvent and reason for that is related to the formation of weak H-bond networks between proton donor chloroform and proton acceptor methanol.
BibTeX: @article{guptaTwoPhotonInducedFluorescenceStudy2020, ids = {guptaTwoPhotonInducedFluorescenceStudy2020a}, title = {Two-{{Photon-Induced Fluorescence Study}} of {{Rhodamine-6G Dye}} in {{Different Sets}} of {{Binary Solvents}}}, author = {Gupta, Rahul Kumar and Kant, Surya and Rawat, Ashwini Kumar and Goswami, Debabrata}, date = {2020-07-01}, journaltitle = {Journal of Fluorescence}, shortjournal = {J Fluoresc}, issn = {1573-4994}, doi = {10.1007/s10895-020-02577-0}, url = {10.1007/s10895-020-02577-0}, urldate = {2020-07-11} } -
Investigating the pH Dependence of Thermal Signatures in Monohydric and Polyhydric Alcohols Using Time-Resolved Thermal Lens Spectroscopy.
A. K. Rawat, S. Chakraborty, A. K. Mishra, and D. Goswami, Optical Materials 137, 113623 (2023)
[Abstract]
[PDF]
[BibTeX]
Abstract: We study the influence of pH on the thermophysical properties of monohydric and polyhydric alcohols through a femtosecond laser-induced thermal lens (TL) spectroscopic technique. Relative changes in the thermal signatures of monohydric and polyhydric alcohols are identified at different pH levels using both dual-beam Z-scan and time-resolved TL measurements. We found the TL signatures of the alcohols not to be affected in the acidic region, but a significant change is noticed in the alkaline environment. It is observed that in an alkaline environment (pH > 7), the TL signal significantly increases for short-chain (MeOH and EtOH) monohydric alcohols. In contrast, the TL signal for longer chain length monohydric alcohols (HxOH and phenol) and polyhydroxy alcohols (Ethylene glycol & Glycerol) fall enormously. These results depend strongly on the molecular characteristics of solvents and their interaction strength with the solute as a function of changing pH strength. Our results show the influence of pH on the natural drifting and the heat dissipation characteristics of solvent molecules, which prominently participate in changing the TL signatures of samples. This event could be attributed to changes in molecular arrangements by developing solvation shells (through ions-solvents interactions) in the systems. We investigate the influence of various factors, namely, chain length, structure, polarity, and inter or the intra-H-bonding ability of solvent molecules and ion concentration, which effectively alter the solute-solvent interaction strengths at different pH values (especially in an alkaline environment). The findings through our TL measurements explore this event in great detail for the first time. We try to correlate the molecular characteristics and its ions-solvent interaction effects with the thermophysical properties of alcohols.
BibTeX: @article{rawatInvestigatingPHDependence2023, title = {Investigating the {{pH}} Dependence of Thermal Signatures in Monohydric and Polyhydric Alcohols Using Time-Resolved Thermal Lens Spectroscopy}, author = {Rawat, Ashwini Kumar and Chakraborty, Subhajit and Mishra, Amit Kumar and Goswami, Debabrata}, date = {2023-03-01}, journaltitle = {Optical Materials}, shortjournal = {Optical Materials}, volume = {137}, pages = {113623}, issn = {0925-3467}, doi = {10.1016/j.optmat.2023.113623}, url = {https://www.sciencedirect.com/science/article/pii/S0925346723001957}, urldate = {2023-07-28} } -
Thermal Inflection Study of Methanol-Hexane Mixtures Using Time-Resolved Thermal Lens Technique.
A. K. Rawat, S. Chakraborty, and D. Goswami, in 2019 Workshop on Recent Advances in Photonics (WRAP) (2019), pp. 1–3
[Abstract]
[PDF]
[BibTeX]
Abstract: Time-resolved thermal lens (TL) technique is used to measure the heat transfer in pure methanol and its binary mixtures with hexane. We used dual-beam mode mismatched pump-probe scheme where a femtosecond laser beam of 1560 nm was used as a pump beam, and its frequency-doubled 780 nm beam was used as probe beam. TL Signal decreases with increasing concentration of hexane in the binary mixture. On higher concentration of Hexane in binary mixture then we have found convective heat transfer mode was absent. At 40%-60% methanol hexane mixture, we observed a sudden curious jump in TL signal.
BibTeX: @inproceedings{rawatThermalInflectionStudy2019, ids = {rawatThermalInflectionStudy2019a}, title = {Thermal {{Inflection Study}} of {{Methanol-Hexane Mixtures}} Using {{Time-Resolved Thermal Lens Technique}}}, booktitle = {2019 {{Workshop}} on {{Recent Advances}} in {{Photonics}} ({{WRAP}})}, author = {Rawat, Ashwini Kumar and Chakraborty, Subhajit and Goswami, Debabrata}, date = {2019-12}, pages = {1--3}, issn = {null}, doi = {10.1109/WRAP47485.2019.9013736}, url = {10.1109/WRAP47485.2019.9013736}, eventtitle = {2019 {{Workshop}} on {{Recent Advances}} in {{Photonics}} ({{WRAP}})} } -
Unraveling Molecular Interactions in Binary Liquid Mixtures with Time-Resolved Thermal-Lens-Spectroscopy.
A. K. Rawat, S. Chakraborty, A. K. Mishra, and D. Goswami, Journal of Molecular Liquids 336, 116322 (2021)
[Abstract]
[PDF]
[BibTeX]
Abstract: Non-contact localized laser heating-based thermal lensing has emerged as a technique for probing the heat transport in liquids. A mode-mismatched dual-beam pump–probe spectroscopic technique was employed to investigate the photothermal response and modes of heat dissipation in methanol and binary mixtures of methanol with polar (water, methanol (MeOH)) and nonpolar (CCl4) solvents. We recorded the time-resolved thermal lens (TL) signal of a probe beam at 780 nm after heat deposition by a 1560 nm pump beam. For pure solvents, the TL signal was found to be approximately one order of magnitude larger for methanol than for water, DMSO, or CCl4, implying that the energy deposition is larger for methanol than for any of the other solvents. Subsequently, binary mixtures were studied where the TL signal increased with an increase in the volume fraction of methanol. All TL signals are shown to have a physical interpretation in terms of heat conduction and convection. In the case of methanol–water, the observed trend can be rationalized in terms of a strong intermolecular interaction. Convective heat transfer is shown to dominate the overall heat transfer in pure methanol and in binary mixtures for all volume fractions where MeOH is in excess of 50%. No convection is observed for very dilute mixtures with a small amount of methanol; in this case, heat conduction is sufficient to reach equilibration. Interestingly, for binary mixtures of methanol with DMSO or water, a decreasing trend is observed in the concentration range between 90% and 100% volume fraction of methanol. We observe also that the TL signal is modified in case of intermolecular interactions forming large clusters of methanol with the cosolvent. In such cases, heat diffusion is affected. Thus, TL can be seen as a sensitive probe for intermolecular interactions as well.
BibTeX: @article{rawatUnravelingMolecularInteractions2021, title = {Unraveling Molecular Interactions in Binary Liquid Mixtures with Time-Resolved Thermal-Lens-Spectroscopy}, author = {Rawat, Ashwini Kumar and Chakraborty, Subhajit and Mishra, Amit Kumar and Goswami, Debabrata}, date = {2021-08-15}, journaltitle = {Journal of Molecular Liquids}, shortjournal = {Journal of Molecular Liquids}, volume = {336}, pages = {116322}, issn = {0167-7322}, doi = {10.1016/j.molliq.2021.116322}, url = {https://www.sciencedirect.com/science/article/pii/S0167732221010461}, urldate = {2023-07-28} }
Diluting Convective Effects in Femtosecond Laser Induced Thermal Lens Measurements with Thermally Active Constituents.
S. Chakraborty, A. K. Mishra, A. K. Rawat, and D. Goswami, in Frontiers in Optics + Laser Science 2022 (FIO, LS) (2022), Paper JW5A.25 (Optica Publishing Group, 2022), p. JW5A.25
<a onclick="toggle('chakrabortyDilutingConvectiveEffects2022_abstract')">[Abstract]</a>
<a href="https://opg.optica.org/abstract.cfm?uri=FiO-2022-JW5A.25">[PDF]</a>
[BibTeX] </span>
<p class="abstract chakrabortyDilutingConvectiveEffects2022_abstract" id="chakrabortyDilutingConvectiveEffects2022_abstract"> <b>Abstract:</b> We report Thermal Lens measurements on the binary liquid mixtures of Methanol and Phenol with femtosecond pulse excitations. The photothermal response is found to be strongly dependent on relative concentrations and the constituents’ molecular properties.</p>
<pre class="bibtex chakrabortyDilutingConvectiveEffects2022_bibtex" id="chakrabortyDilutingConvectiveEffects2022_bibtex"> <b>BibTeX:</b> @inproceedings{chakrabortyDilutingConvectiveEffects2022, title = {Diluting {{Convective Effects}} in {{Femtosecond Laser Induced Thermal Lens Measurements}} with {{Thermally Active Constituents}}}, booktitle = {Frontiers in {{Optics}} + {{Laser Science}} 2022 ({{FIO}}, {{LS}}) (2022), Paper {{JW5A}}.25}, author = {Chakraborty, Subhajit and Mishra, Amit Kumar and Rawat, Ashwini Kumar and Goswami, Debabrata}, date = {2022-10-17}, pages = {JW5A.25}, publisher = {{Optica Publishing Group}}, url = {https://opg.optica.org/abstract.cfm?uri=FiO-2022-JW5A.25}, urldate = {2022-12-31}, eventtitle = {Frontiers in {{Optics}}} }
</pre>
</li>
Abstract: Mode Mismatched Pump-Probe spectroscopic method was employed to examine the thermally induced nonlinear optical properties of methanol and its binary mixtures. The heat transfer mechanism in methanol and its binary mixtures with carbon tetrachloride (CCl4) at different concentrations of methanol is investigated. Methanol has the highest Thermal Lens (TL) signal, and CCl4 does not have any TL signal at all. However, the presence of CCl4 modulates the TL signal of the binary mixture. The time-domain shift in TL signal is observed for different concentrations of methanol, which indicates the unusual molecular behavior in the binary mixture.
BibTeX: @inproceedings{chakrabortySensingMolecularProperties2019,
title = {Sensing the {{Molecular Properties}} in {{Methanol}} and Its {{Binary Mixtures}} Using {{Time-Resolved Thermal Lens Spectrometer}}},
booktitle = {2019 {{Workshop}} on {{Recent Advances}} in {{Photonics}} ({{WRAP}})},
author = {Chakraborty, Subhajit and Rawat, Ashwini Kumar and Goswami, Debabrata},
date = {2019-12},
pages = {1--3},
issn = {null},
doi = {10.1109/WRAP47485.2019.9013697},
eventtitle = {2019 {{Workshop}} on {{Recent Advances}} in {{Photonics}} ({{WRAP}})}
}
Abstract: We performed a dual beam Z-Scan experiment to examine the thermal lensing effects in CBNP nanofluids. The photothermal characteristics and heat dissipation dynamics were observed for these nanofluids at different levels of their linear absorption.
BibTeX: @inproceedings{chakrabortyUnderstandingPhotothermalResponse2021,
title = {Understanding the {{Photothermal Response}} of {{CBNP Nanofluids Using Thermal Lens Spectroscopic Techniques}}},
booktitle = {Frontiers in {{Optics}} + {{Laser Science}} 2021 (2021), Paper {{JTu1A}}.99},
author = {Chakraborty, Subhajit and Mishra, Amit Kumar and Rawat, Ashwini Kumar and Goswami, Debabrata},
date = {2021-11-01},
pages = {JTu1A.99},
publisher = {{Optica Publishing Group}},
doi = {10.1364/FIO.2021.JTu1A.99},
url = {https://opg.optica.org/abstract.cfm?uri=LS-2021-JTu1A.99},
urldate = {2022-12-31},
eventtitle = {Laser {{Science}}}
}
Abstract: Time-resolved thermal lens (TL) technique is used to measure the heat transfer in pure methanol and its binary mixtures with hexane. We used dual-beam mode mismatched pump-probe scheme where a femtosecond laser beam of 1560 nm was used as a pump beam, and its frequency-doubled 780 nm beam was used as probe beam. TL Signal decreases with increasing concentration of hexane in the binary mixture. On higher concentration of Hexane in binary mixture then we have found convective heat transfer mode was absent. At 40%-60% methanol hexane mixture, we observed a sudden curious jump in TL signal.
BibTeX: @inproceedings{rawatThermalInflectionStudy2019,
ids = {rawatThermalInflectionStudy2019a},
title = {Thermal {{Inflection Study}} of {{Methanol-Hexane Mixtures}} Using {{Time-Resolved Thermal Lens Technique}}},
booktitle = {2019 {{Workshop}} on {{Recent Advances}} in {{Photonics}} ({{WRAP}})},
author = {Rawat, Ashwini Kumar and Chakraborty, Subhajit and Goswami, Debabrata},
date = {2019-12},
pages = {1--3},
issn = {null},
doi = {10.1109/WRAP47485.2019.9013736},
url = {10.1109/WRAP47485.2019.9013736},
eventtitle = {2019 {{Workshop}} on {{Recent Advances}} in {{Photonics}} ({{WRAP}})}
}
</ol> –>