Amit Nag

Professor, BITS Pilani, Hyderabad Campus, India

Education / Work History

Professor, BITS Pilani, Hyderabad Campus, India (2023-present)
Associate Professor, BITS Pilani, Hyderabad Campus, India (2018-2023)
Assistant Professor, BITS Pilani, Hyderabad Campus, India (2012-2018)
Post-doctoral researcher, LMU, Munich, Germany (2011 - 2012)
Post-doctoral researcher, University of California, Irvine, CA, USA (2009-2011)
Post-doctoral researcher, Princeton University, Princeton, NJ, USA (Fall 2009)
Ph.D., Scholar, IIT Kanpur (2009)
M.Sc., Jadavpur University, Kolkata, W.B., India (2003)
B.Sc., Burdwan Raj College,University of Burdwan, Burdwan, W.B., India (2001)

Thesis Abstract

Accurate Quantification and Control of Two-Photon Processes

The main theme of the thesis is to understand the two-photon process, its accurate quantification and control using femtosecond pulsed lasers. This effort culminated in identifying control parameters. The thesis has been organized into seven chapters. The introductory Chapter 1 starts with the brief history of the two-photon absorption (TPA) process, basic concepts and its significant applications in different areas of science. A general importance of the TPA related studies and a brief review of these studies performed by other research groups have been presented. In Chapter 2, the principles, technical details of different experimental setups to measure the TPA process and different pulse characterization techniques are described in detail. Chapter 3 of the thesis describes sensitive measurements of large TPA cross-section (TPCS) values of different chromophores starting from modified porphyrin to simple co-ordination metal complexes using open aperture z-scan method with high repetition rate (HRR) MHz lasers. Very small nonlinearities of neat solvent molecules are also described. The pulse pileup problems and cumulative thermal effects are the major difficulties to apprehend in the experiments using HRR lasers. In Chapter 4, it has been shown that an optical chopper can be optimized to sufficiently minimize the thermal contributions of HRR lasers by periodic blanking of the laser pulses to the system under study. This particular study also unifies the TPCS measurements from z-scan and two-photon fluorescence (TPF) techniques. In Chapter 5, experimental observations are presented on how solvents can vary the TPA and TPF properties of fluorescent dyes. Chapter 6 presents an interesting study of modulation of TPF through variation of the incident laser polarization for different fluorescent dyes. In Chapter 7, the design of a folded geometry acousto-optic modulator based pulse shaper is discussed, which is capable of shaping individual pulses from a kHz amplified laser. Once the pulse shaping scheme is established and characterized, we experimentally study the variation of TPA and TPF for several chromophores in solutions by simple phase ordering a femtosecond laser pulse.

Research Topic / Interest

Contact me to know my current interests.

Publications

These include only those published in our lab.

Effect of Linear Chirp on Femtosecond Two-Photon Processes in Solution. A. Nag and D. Goswami, Journal of spectroscopy and dynamics 2(3), (2012)

BibTeX: @article{nagEffectLinearChirp2012,
  title = {Effect of Linear Chirp on Femtosecond Two-Photon Processes in Solution},
  author = {Nag, Amit and Goswami, Debabrata},
  year = {2012},
  month = aug,
  journal = {Journal of spectroscopy and dynamics},
  volume = {2},
  number = {3},
  issn = {2249-2704},
  urldate = {2019-08-02},
  pmcid = {PMC3868930},
  pmid = {24364002},
  annotation = {GSCC: 0000003 \\
  00001}
}

Exploring Control Parameters of Two Photon Processes in Solutions. D. Goswami and A. Nag, Journal of Chemical Sciences 124(1), 281–289 (2012)

BibTeX: @article{goswamiExploringControlParameters2012,
  title = {Exploring Control Parameters of Two Photon Processes in Solutions},
  author = {Goswami, Debabrata and Nag, Amit},
  year = {2012},
  month = jan,
  journal = {Journal of Chemical Sciences},
  volume = {124},
  number = {1},
  pages = {281--289},
  issn = {0973-7103},
  doi = {10/f3wxbj},
  urldate = {2019-08-02},
  langid = {english},
  annotation = {GSCC: 0000123 \\
  3 citations (Crossref) [2024-05-28]\\
  00000}
}

Coumarin Derived Chromophores in the Donor–Acceptor–Donor Format That Gives Fluorescence Enhancement and Large Two-Photon Activity in Presence of Specific Metal Ions. D. Ray, A. Nag, A. Jana, D. Goswami, and P. K. Bharadwaj, Inorganica Chimica Acta 363(12), 2824–2832 (2010)

BibTeX: @article{rayCoumarinDerivedChromophores2010,
  title = {Coumarin Derived Chromophores in the Donor--Acceptor--Donor Format That Gives Fluorescence Enhancement and Large Two-Photon Activity in Presence of Specific Metal Ions},
  author = {Ray, Debdas and Nag, Amit and Jana, Atanu and Goswami, Debabrata and Bharadwaj, Parimal K.},
  year = {2010},
  month = oct,
  journal = {Inorganica Chimica Acta},
  series = {Special Volume: {{Dedicated}} to {{Professor Animesh Chakravorty}}},
  volume = {363},
  number = {12},
  pages = {2824--2832},
  issn = {0020-1693},
  doi = {10/c2k85x},
  urldate = {2019-08-14},
  annotation = {GSCC: 0000043 \\
  33 citations (Crossref) [2024-05-28]\\
  00029}
}

Polarization Induced Control of Single and Two-Photon Fluorescence. A. Nag and D. Goswami, The Journal of Chemical Physics 132(15), 154508 (2010)

BibTeX: @article{nagPolarizationInducedControl2010,
  title = {Polarization Induced Control of Single and Two-Photon Fluorescence},
  author = {Nag, Amit and Goswami, Debabrata},
  year = {2010},
  month = apr,
  journal = {The Journal of Chemical Physics},
  volume = {132},
  number = {15},
  pages = {154508},
  issn = {0021-9606},
  doi = {10/bdr2kh},
  urldate = {2019-08-14},
  annotation = {GSCC: 0000027 \\
  22 citations (Crossref) [2024-05-28]\\
  00022}
}

Applying Genetic Algorithm Optimization to a Folded Geometry Acousto-Optic Modulated Spatial Pulse Shaper. A. Nag, P. A. Chaphekar, and D. Goswami, Review of Scientific Instruments 81(1), 013101 (2010)

BibTeX: @article{nagApplyingGeneticAlgorithm2010,
  title = {Applying Genetic Algorithm Optimization to a Folded Geometry Acousto-Optic Modulated Spatial Pulse Shaper},
  author = {Nag, Amit and Chaphekar, Prasad A. and Goswami, Debabrata},
  year = {2010},
  month = jan,
  journal = {Review of Scientific Instruments},
  volume = {81},
  number = {1},
  pages = {013101},
  issn = {0034-6748},
  doi = {10/ddkc77},
  urldate = {2019-08-14},
  annotation = {GSCC: 0000008 \\
  5 citations (Crossref) [2024-05-28]\\
  00004}
}

Solvent Effect on Two-Photon Absorption and Fluorescence of Rhodamine Dyes. A. Nag and D. Goswami, Journal of Photochemistry and Photobiology A: Chemistry 206(2), 188–197 (2009)

BibTeX: @article{nagSolventEffectTwophoton2009,
  title = {Solvent Effect on Two-Photon Absorption and Fluorescence of Rhodamine Dyes},
  author = {Nag, Amit and Goswami, Debabrata},
  year = {2009},
  month = aug,
  journal = {Journal of Photochemistry and Photobiology A: Chemistry},
  volume = {206},
  number = {2},
  pages = {188--197},
  issn = {1010-6030},
  doi = {10/c4zdx8},
  urldate = {2019-08-14},
  annotation = {GSCC: 0000110 \\
  83 citations (Crossref) [2024-05-28]\\
  00063}
}

Two-Photon Cross-Section Measurements Using an Optical Chopper: Z-Scan and Two-Photon Fluorescence Schemes. A. Nag, A. K. De, and D. Goswami, Journal of Physics B: Atomic, Molecular and Optical Physics 42(6), 065103 (2009)

BibTeX: @article{nagTwophotonCrosssectionMeasurements2009,
  title = {Two-Photon Cross-Section Measurements Using an Optical Chopper: Z-Scan and Two-Photon Fluorescence Schemes},
  shorttitle = {Two-Photon Cross-Section Measurements Using an Optical Chopper},
  author = {Nag, Amit and De, Arijit Kumar and Goswami, Debabrata},
  year = {2009},
  month = mar,
  journal = {Journal of Physics B: Atomic, Molecular and Optical Physics},
  volume = {42},
  number = {6},
  pages = {065103},
  issn = {0953-4075, 1361-6455},
  doi = {10/bhffqb},
  urldate = {2018-12-10},
  annotation = {GSCC: 0000049 \\
  39 citations (Crossref) [2024-05-28]\\
  00000}
}

Acyclic Donor–Acceptor–Donor Chromophores for Large Enhancement of Two-Photon Absorption Cross-Section in the Presence of Mg(II), Ca(II) or Zn(II) Ions. D. Ray, A. Nag, D. Goswami, and P. K. Bharadwaj, Journal of Luminescence 129(3), 256–262 (2009)

BibTeX: @article{rayAcyclicDonorAcceptor2009,
  title = {Acyclic Donor--Acceptor--Donor Chromophores for Large Enhancement of Two-Photon Absorption Cross-Section in the Presence of {{Mg}}({{II}}), {{Ca}}({{II}}) or {{Zn}}({{II}}) Ions},
  author = {Ray, Debdas and Nag, Amit and Goswami, Debabrata and Bharadwaj, Parimal K.},
  year = {2009},
  month = mar,
  journal = {Journal of Luminescence},
  volume = {129},
  number = {3},
  pages = {256--262},
  issn = {0022-2313},
  doi = {10.1016/j.jlumin.2008.10.005},
  urldate = {2019-08-14},
  annotation = {GSCC: 0000011 \\
  10 citations (Crossref) [2024-05-28]}
}

Diaza-18-Crown-6 Based Chromophores for Modulation of Two-Photon Absorption Cross-Section by Metal Ions. A. Jana, A. Kumar De, A. Nag, D. Goswami, and P. K. Bharadwaj, Journal of Organometallic Chemistry 693(7), 1186–1194 (2008)

BibTeX: @article{janaDiaza18crown6BasedChromophores2008,
  title = {Diaza-18-Crown-6 Based Chromophores for Modulation of Two-Photon Absorption Cross-Section by Metal Ions},
  author = {Jana, Atanu and Kumar De, Arijit and Nag, Amit and Goswami, Debabrata and Bharadwaj, Parimal K.},
  year = {2008},
  month = apr,
  journal = {Journal of Organometallic Chemistry},
  volume = {693},
  number = {7},
  pages = {1186--1194},
  issn = {0022-328X},
  doi = {10/cdtg8k},
  urldate = {2019-08-14},
  annotation = {GSCC: 0000008 \\
  6 citations (Crossref) [2024-05-28]}
}

Optical Enhancement of Two-Photon Absorption Process. D. Goswami, S. Ashtekar, and A. Nag, (March 19, 2008)

BibTeX: @patent{goswamiOpticalEnhancementTwophoton2008,
  title = {Optical Enhancement of Two-Photon Absorption Process},
  author = {Goswami, Debabrata and Ashtekar, Sumit and Nag, Amit},
  year = {2008},
  month = mar,
  day = {19},
  number = {704/DEL/2008},
  type = {Indian Patent Application},
  note = {Filed 19 March 2008; published as IN 2008DE00704 A, 2 October 2009},
  langid = {english}
}

Metal Induced Enhancement of Fluorescence and Modulation of Two-Photon Absorption Cross-Section with a Donor–Acceptor–Acceptor–Donor Receptor. S. Das, A. Nag, K. K. Sadhu, D. Goswami, and P. K. Bharadwaj, Journal of Organometallic Chemistry 692(22), 4969–4977 (2007)

BibTeX: @article{dasMetalInducedEnhancement2007,
  title = {Metal Induced Enhancement of Fluorescence and Modulation of Two-Photon Absorption Cross-Section with a Donor--Acceptor--Acceptor--Donor Receptor},
  author = {Das, Sanjib and Nag, Amit and Sadhu, Kalyan K. and Goswami, Debabrata and Bharadwaj, Parimal K.},
  year = {2007},
  month = oct,
  journal = {Journal of Organometallic Chemistry},
  volume = {692},
  number = {22},
  pages = {4969--4977},
  issn = {0022-328X},
  doi = {10/fkrn5p},
  urldate = {2019-08-14},
  annotation = {GSCC: 0000014 \\
  11 citations (Crossref) [2024-05-28]\\
  00014}
}

Nonlinear Optical Properties of Free Standing Films of PbS Quantum Dots in the Nonresonant Femtosecond Regime. P. A. Kurian, C. Vijayan, A. Nag, and D. Goswami, in NanoScience + Engineering, Z. Gaburro and S. Cabrini, eds. (2007), p. 66390M

BibTeX: @inproceedings{kurianNonlinearOpticalProperties2007,
  title = {Nonlinear Optical Properties of Free Standing Films of {{PbS}} Quantum Dots in the Nonresonant Femtosecond Regime},
  booktitle = {{{NanoScience}} + {{Engineering}}},
  author = {Kurian, Pushpa Ann and Vijayan, C. and Nag, Amit and Goswami, Debabrata},
  editor = {Gaburro, Zeno and Cabrini, Stefano},
  year = {2007},
  month = sep,
  pages = {66390M},
  address = {San Diego, California, USA},
  doi = {10/cntz9g},
  urldate = {2019-08-14},
  annotation = {GSCC: 0000003 \\
  1 citations (Crossref) [2024-05-28]}
}

A Sensitive Technique for Two-Photon Absorption Measurements: Towards Higher Resolution Microscopy. A. Nag, A. K. De, and D. Goswami, Journal of Physics: Conference Series 80, 012034 (2007)

BibTeX: @article{nagSensitiveTechniqueTwoPhoton2007,
  title = {A {{Sensitive Technique}} for {{Two-Photon Absorption Measurements}}: {{Towards Higher Resolution Microscopy}}},
  shorttitle = {A {{Sensitive Technique}} for {{Two-Photon Absorption Measurements}}},
  author = {Nag, Amit and De, Arijit Kr and Goswami, Debabrata},
  year = {2007},
  month = sep,
  journal = {Journal of Physics: Conference Series},
  volume = {80},
  pages = {012034},
  issn = {1742-6596},
  doi = {10/bwjg5v},
  urldate = {2019-08-14},
  langid = {english},
  annotation = {GSCC: 0000008 \\
  7 citations (Crossref) [2024-05-28]\\
  00006}
}

One-Pot Synthesis of Core-Modified Rubyrin, Octaphyrin, and Dodecaphyrin: Characterization and Nonlinear Optical Properties. R. Kumar, R. Misra, T. K. Chandrashekar, A. Nag, D. Goswami, E. Suresh, and C. H. Suresh, European Journal of Organic Chemistry 2007(27), 4552–4562 (2007)

BibTeX: @article{kumarOnePotSynthesisCoreModified2007,
  title = {One-{{Pot Synthesis}} of {{Core-Modified Rubyrin}}, {{Octaphyrin}}, and {{Dodecaphyrin}}: {{Characterization}} and {{Nonlinear Optical Properties}}},
  shorttitle = {One-{{Pot Synthesis}} of {{Core-Modified Rubyrin}}, {{Octaphyrin}}, and {{Dodecaphyrin}}},
  author = {Kumar, Rajeev and Misra, Rajneesh and Chandrashekar, Tavarekere K. and Nag, Amit and Goswami, Debabrata and Suresh, Eringathodi and Suresh, Cherumuttathu H.},
  year = {2007},
  journal = {European Journal of Organic Chemistry},
  volume = {2007},
  number = {27},
  pages = {4552--4562},
  issn = {1099-0690},
  doi = {10/bwctt3},
  urldate = {2019-08-14},
  copyright = {Copyright \copyright{} 2007 WILEY-VCH Verlag GmbH \& Co. KGaA, Weinheim},
  langid = {english},
  annotation = {GSCC: 0000017 \\
  22 citations (Crossref) [2024-05-28]\\
  00017}
}

22\pi Smaragdyrin Molecular Conjugates with Aromatic Phenylacetylenes and Ferrocenes: Syntheses, Electrochemical, and Photonic Properties. R. Misra, R. Kumar, T. K. Chandrashekar, C. H. Suresh, A. Nag, and D. Goswami, Journal of the American Chemical Society 128(50), 16083–16091 (2006)

BibTeX: @article{misra22pSmaragdyrinMolecular2006,
  title = {22{$\pi$} {{Smaragdyrin Molecular Conjugates}} with {{Aromatic Phenylacetylenes}} and {{Ferrocenes}}:\, {{Syntheses}}, {{Electrochemical}}, and {{Photonic Properties}}},
  shorttitle = {22{$\pi$} {{Smaragdyrin Molecular Conjugates}} with {{Aromatic Phenylacetylenes}} and {{Ferrocenes}}},
  author = {Misra, Rajneesh and Kumar, Rajeev and Chandrashekar, Tavarekere K. and Suresh, C. H. and Nag, Amit and Goswami, Debabrata},
  year = {2006},
  month = dec,
  journal = {Journal of the American Chemical Society},
  volume = {128},
  number = {50},
  pages = {16083--16091},
  issn = {0002-7863},
  doi = {10/ds2r2p},
  urldate = {2019-08-14},
  annotation = {GSCC: 0000080 \\
  75 citations (Crossref) [2024-05-28]\\
  00072}
}

Structure Property Correlations in Alcohols through Two-Photon Absorption Cross-Section Measurements. A. Nag, S. Singh, and D. Goswami, Chemical Physics Letters 430(4), 420–423 (2006)

BibTeX: @article{nagStructurePropertyCorrelations2006,
  title = {Structure Property Correlations in Alcohols through Two-Photon Absorption Cross-Section Measurements},
  author = {Nag, Amit and Singh, Sherdeep and Goswami, Debabrata},
  year = {2006},
  month = oct,
  journal = {Chemical Physics Letters},
  volume = {430},
  number = {4},
  pages = {420--423},
  issn = {0009-2614},
  doi = {10/dbmk87},
  urldate = {2019-08-14},
  annotation = {GSCC: 0000009 \\
  8 citations (Crossref) [2024-05-28]\\
  00009}
}

Aromatic Core Modified Decaphyrins with the Largest Two-Photon Absorption Cross-Sections: Syntheses and Characterization. H. Rath, V. Prabhuraja, T. K. Chandrashekar, A. Nag, D. Goswami, and B. S. Joshi, Organic Letters 8(11), 2325–2328 (2006)

BibTeX: @article{rathAromaticCoreModified2006,
  title = {Aromatic {{Core Modified Decaphyrins}} with the {{Largest Two-Photon Absorption Cross-Sections}}:\, {{Syntheses}} and {{Characterization}}},
  shorttitle = {Aromatic {{Core Modified Decaphyrins}} with the {{Largest Two-Photon Absorption Cross-Sections}}},
  author = {Rath, Harapriya and Prabhuraja, Viswanathan and Chandrashekar, Tavarekere K. and Nag, Amit and Goswami, Debabrata and Joshi, Bhawani S.},
  year = {2006},
  month = may,
  journal = {Organic Letters},
  volume = {8},
  number = {11},
  pages = {2325--2328},
  issn = {1523-7060},
  doi = {10/cwgk39},
  urldate = {2019-08-14},
  annotation = {GSCC: 0000062 \\
  58 citations (Crossref) [2024-05-28]}
}

Modified (22\pi) Smaragdyrins with Large Two-Photon Absorption Cross Section: A Structure Function Correlation. R. Misra, R. Kumar, T. K. Chandrashekar, A. Nag, and D. Goswami, Organic Letters 8(4), 629–631 (2006)

BibTeX: @article{misraModified22pSmaragdyrins2006,
  title = {Modified (22{$\pi$}) {{Smaragdyrins}} with {{Large Two-Photon Absorption Cross Section}}:\, {{A Structure Function Correlation}}},
  shorttitle = {Modified (22{$\pi$}) {{Smaragdyrins}} with {{Large Two-Photon Absorption Cross Section}}},
  author = {Misra, Rajneesh and Kumar, Rajeev and Chandrashekar, Tavarekere K. and Nag, Amit and Goswami, Debabrata},
  year = {2006},
  month = feb,
  journal = {Organic Letters},
  volume = {8},
  number = {4},
  pages = {629--631},
  issn = {1523-7060},
  doi = {10/dhmkht},
  urldate = {2019-08-14},
  annotation = {GSCC: 0000047 \\
  42 citations (Crossref) [2024-05-28]\\
  00044}
}

Zinc(II)- and Copper(I)-Mediated Large Two-Photon Absorption Cross Sections in a Bis-cinnamaldiminato Schiff Base. S. Das, A. Nag, D. Goswami, and P. K. Bharadwaj, Journal of the American Chemical Society 128(2), 402–403 (2006)

BibTeX: @article{dasZincIICopperIMediatedLarge2006,
  title = {Zinc({{II}})- and {{Copper}}({{I}})-{{Mediated Large Two-Photon Absorption Cross Sections}} in a {{Bis-cinnamaldiminato Schiff Base}}},
  author = {Das, Sanjib and Nag, Amit and Goswami, Debabrata and Bharadwaj, Parimal K.},
  year = {2006},
  month = jan,
  journal = {Journal of the American Chemical Society},
  volume = {128},
  number = {2},
  pages = {402--403},
  issn = {0002-7863},
  doi = {10/bccmmp},
  urldate = {2019-08-14},
  annotation = {GSCC: 0000153 \\
  131 citations (Crossref) [2024-05-28]\\
  00134}
}

Core-Modified Expanded Porphyrins with Large Third-Order Nonlinear Optical Response. H. Rath, J. Sankar, V. PrabhuRaja, T. K. Chandrashekar, A. Nag, and D. Goswami, Journal of the American Chemical Society 127(33), 11608–11609 (2005)

BibTeX: @article{rathCoreModifiedExpandedPorphyrins2005,
  title = {Core-{{Modified Expanded Porphyrins}} with {{Large Third-Order Nonlinear Optical Response}}},
  author = {Rath, Harapriya and Sankar, Jeyaraman and PrabhuRaja, Viswanathan and Chandrashekar, Tavarekere K. and Nag, Amit and Goswami, Debabrata},
  year = {2005},
  month = aug,
  journal = {Journal of the American Chemical Society},
  volume = {127},
  number = {33},
  pages = {11608--11609},
  issn = {0002-7863},
  doi = {10/c2tqsv},
  urldate = {2019-08-14},
  annotation = {GSCC: 0000204 \\
  178 citations (Crossref) [2024-05-28]\\
  00160}
}