High School (A J I C Tanda Faizabad)
Intermediate (Adarsh Janta I C Tanda Ambedkar Nagar)
BSc (Hons) (Aligarh Muslim University)
MSc (IIT Kanpur)
PhD (IIT Kanpur)
Post Doc (IIT Bombay)
RESEARCH, TEACHING, or OTHER INTERESTS
Multidisciplinary, Atomic and Molecular Physics, and Optics, Biophysics, Biotechnology
15
Scopus Publications
142
Scholar Citations
5
Scholar h-index
5
Scholar i10-index
Scopus Publications
Fluorescence scattering under the Stokes-Mueller formalism determines the orientational distribution of fluorophores and the nature of optically active biological proteins Mohammad Zaffar Journal of Optics United Kingdom, 2024 In the current paper, we represent intrinsic fluorescence anisotropies as four-dimensional normalized Stokes vectors defined by the maximum excitation and emission in the fluorescence process with respect to linear, linear-45 and circular polarizations of light. Depending upon the transition moments for absorption/excitation and emission of fluorophores, eight types of these Stokes vectors can be realized from the Mueller fluorescence matrix of the system. These Stokes vectors probe the orientational distribution of fluorophores and predict the nature of optically active biological proteins, whether laevorotatory or dextrorotatory. The orthogonality relation between the Stokes vectors corresponding to the excitation and emission processes of fluorescence connects the molecular ground and excited states of biological and non-biological systems.
Laser speckle correlation microscopy system to image microvascular perfusion Soumyajit Sarkar, Mohammad Zaffar, Hari M. Varma Proceedings of SPIE the International Society for Optical Engineering, 2023 Laser speckle contrast imaging (LSCI) methods are extensively used in assessment of blood flow to detect various pathological conditions in different parts of human body. In contrast to LSCI being deployed for larger region of interest (few centimeters), we present a laser speckle imaging at microscopic level. Rather than utilizing the conventional speckle contrast, we use intensity auto-correlation using recently developed Multi-step Volterra Integral method(MVIM) to quantify the micro-perfusion. The proposed laser speckle correlation microscopy (LSCM) system is validated using microfluidic flow phantom experiments.
Laser speckle correlation microscopy system to image microvascular perfusion Soumyajit Sarkar, Mohammad Zaffar, Hari M. Varma European Conference on Biomedical Optics Ecbo 2023, 2023 Laser speckle contrast imaging (LSCI) methods are extensively used in assessment of blood flow to detect various pathological conditions in different parts of human body. In contrast to LSCI being deployed for larger region of interest (few centimeters), we present a laser speckle imaging at microscopic level. Rather than utilizing the conventional speckle contrast, we use intensity auto-correlation using recently developed Multi-step Volterra Integral method(MVIM) to quantify the micro-perfusion. The proposed laser speckle correlation microscopy (LSCM) system is validated using microfluidic flow phantom experiments.
Fiber-conduit based Laser Speckle Contrast Imaging device for point of care diagnostics Ria Paul, Susweta Das, Soumyajit Sarkar, Mohammad Zaffar, Hari M. Varma Proceedings of SPIE the International Society for Optical Engineering, 2023 We present a laser speckle contrast imaging (LSCI) device equipped with an image conduit to image microvascular blood flow in remote tissues like ear, nose, throat (ENT) and cervical region. The system is validated using a tissue mimicking microfluidic flow phantom with different widths and flow speeds. The proposed system is being developed as a point of care testing (POCT) device best suited for at-home self-monitoring in resource-limited areas as it is non-invasive, portable, affordable and real time.
Fiber-conduit based Laser Speckle Contrast Imaging device for point of care diagnostics Ria Paul, Susweta Das, Soumyajit Sarkar, Mohammad Zaffar, Hari M. Varma European Conference on Biomedical Optics Ecbo 2023, 2023 We present a laser speckle contrast imaging (LSCI) device equipped with an image conduit to image microvascular blood flow in remote tissues like ear, nose, throat (ENT) and cervical region. The system is validated using a tissue mimicking microfluidic flow phantom with different widths and flow speeds. The proposed system is being developed as a point of care testing (POCT) device best suited for at-home self-monitoring in resource-limited areas as it is non-invasive, portable, affordable and real time.
Fluorescence scattering in between excitation and emission as a depolarizing process: a Mueller matrix viewpoint Mohammad Zaffar Journal of the Optical Society of America A Optics and Image Science and Vision, 2022 A rigorous model has been proposed to qualify fluorescence scattering through the Mueller matrix viewpoint in terms of absorption/excitation, emission, and the process in between them. The process in between the excitation and emission processes of fluorescence, irrespective of the scattering directions, has been modeled as a depolarization process. The absorption/excitation of the fluorophore molecules gets revealed through the first-row elements while the emission of fluorescence has been observed through the first column elements of the fluorescence Mueller matrix. Information of the transitions between the molecular ground and excited states gets encoded into the diagonal elements following the photon selection rule. The other off-diagonal elements of the fluorescence Mueller matrix also exhibit very small nonzero values due to the anisotropic absorption and phase changes that the ground state of the fluorophore molecules imposes on the incident polarized beam while parallelly governing the emitted beam. The comparison of the current model with the earlier model has been discussed in a detailed way. The modeling of the in-between process as the depolarizing one enables us to qualify the fluorescence detected linear and circular dichroism and luminescence and very effectively overcomes the shortcomings in the earlier model.
Spatial autocorrelation analysis on two-dimensional images of Mueller matrix for diagnosis and differentiation of cervical precancer Mohammad Zaffar, Asima Pradhan Journal of Biophotonics, 2020 The spatial autocorrelation and correlation map of amplitude and phase anisotropy along with depolarization parameter from the stroma of uterine cervix utilizing their Mueller matrix (MM) images have been reported for early diagnosis of cervical cancer and differentiation of precancerous stages. The comparative results of the evaluation of the spatial autocorrelation over MM images of optically anisotropic collagen structures from normal and various grades of cervical precancer reflect significant alterations which are correlated with the pathological changes. The spatially varying polarizance from different region of anisotropic stromal region gets correlated within a given spatial lag during the precancerous changes. The diattenuation governing elements M12, M13 and M14 clearly discriminate normal and various grades of precancerous cervical tissue through their autocorrelation profile and correlation map. Evaluation of autocorrelation of spatially varying linear birefringence and linear‐45 birefringence characterized by MM elements M34 and M43 and M24 and M42 are not found to differ between the precancer grades, indicating that these changes may be arising from highly directional collagen network while the changes displayed by MM elements M23 and M32 faithfully represent that the chirality of the stromal region is compromised as the cervical cancer evolves and only one type of nature dominates.
Different orders of scattering through time-resolved Mueller matrix imaging estimates of pre-malignancy in human cervical tissues Mohammad Zaffar, Gyana Ranjan Sahoo, Asima Pradhan Applied Optics, 2020 Time-resolved Mueller matrix (MM) imaging polarimetry in transmission mode has been implemented in both epithelium and stromal regions of cervical tissues to explore the various polarization dynamics in connection with the diagnosis of cervical precancer. The picosecond-resolved intensity patterns of various MM elements, resulting from the various orders of scattering, at different time delays provide clear demarcation between the epithelium and stroma of cervical tissue. The time dependent depolarization and retardance maps are seen to differentiate the epithelium from stroma. The average values of time dependent linear, linear-45, and circular depolarization and linear, circular, and scalar retardance parameters in different regimes of scattering from the optically anisotropic stromal region identify the pre-malignancy in cervical tissue. As the disease evolves, time dependent linear depolarization varies to larger values as compared to time dependent circular depolarization. Interestingly, the chirality of the collagen network that rotates the plane of polarized light in either direction in normal samples is limited to only the clockwise direction during the progression of the disease. These results show potential in the early detection and understanding of the mechanisms of morphological changes in cervical cancer development.
Mapping of retardance, diattenuation and polarizance vector on Poincare sphere for diagnosis and classification of cervical precancer Mohammad Zaffar, Asima Pradhan Journal of Biophotonics, 2020 The mapping of diattenuation, polarizance and retardance vector (normalized Stokes vector) on Poincare sphere, evaluated from Mueller matrix of optically anisotropic stromal region of cervical tissues, is presented for cervical precancer detection and its staging. This reveals that the changes in the polarization states shown by these normalized Stokes vectors corresponds to the degradation of linearly arranged collagen fibers, breakage of the collagen cross links in the stromal region and change in the density of scattering sites when cervical cancer evolves. The distinct nature of real and imaginary parts of the refractive index for linear, linear‐45 and circular polarization from the optically anisotropic stromal region underscore the various polarization structures of the connective tissue region which get modified during the pathological changes. It has been found that versatility of these vectors for normal and precancerous cervical tissue of various grades may be utilized as a key distinction for qualitative staging of cervical precancer tissue. Quantitative classification of precancerous stages of cervical precancer has been determined with 95%–100% sensitivity and 93%–100% specificity through the evaluation of linear and circular diattenuation, linear polarizance and linear birefringence from the components of the respective vectors.
Assessment of anisotropy of collagen structures through spatial frequencies of Mueller matrix images for cervical pre-cancer detection Mohammad Zaffar, Asima Pradhan Applied Optics, 2020 Analysis of spatial frequency of Mueller matrix (MM) images in the Fourier domain yields quantifying parameters of anisotropy in the stromal region in normal and precancerous tissue sections of human uterine cervix. The spatial frequencies of MM elements reveal reliable information of microscopic structural organization arising from the different orientations of collagen fibers in the connective tissue and their randomization with disease progression. Specifically, the local disorder generated in the normal periodic and regular structure of collagen during the growth of the cervical cancer finds characteristic manifestation in the Fourier spectrum of the selected Mueller matrix elements encoding the anisotropy effects through retardance and birefringence. In contrast, Fourier spectra of differential polarization gated images are limited to only one orientation of collagen. Fourier spectra of first row elements M11, M12, M13, and M14 and first column elements M11, M21, M31, and M41 discriminates cervical inter-epithelial neoplasia (CIN)-I from normal cervical tissue samples with 95%–100% sensitivity and specificity. FFT spectra of first and fourth row elements classify CIN-I and CIN-II grades of cervical cancerous tissues with 90%–100% sensitivity and 87%–100% specificity. Normal and CIN-II grade samples are successfully discriminated through Fourier spectra of every MM element while that of M31 element arises as the key classifier among normal, CIN-I, and CIN-II grades of cervical cancer with 100% sensitivity and specificity. These results demonstrate the promise of spatial frequency analysis of Mueller matrix images as a novel, to the best of our knowledge, approach for cancer/precancer detection.
A POINT-OF-CARE DIAGNOSTIC SYSTEM BASED ON LASER SPECKLE CONTRAST IMAGING (LSCI) USING AN IMAGE CONDUIT Ria PAUL, Susweta DAS, Soumyajit SARKAR, Mohammad ZAFFAR, Hari M VARMA IN Patent 568,348 , 2025 2025
Fluorescence scattering under the Stokes–Mueller formalism determines the orientational distribution of fluorophores and the nature of optically active biological proteins M Zaffar Journal of Optics 26 (12), 125301 , 2024 2024
Laser speckle correlation microscopy system to image microvascular perfusion S Sarkar, M Zaffar, HM Varma European Conference on Biomedical Optics, 1262827 , 2023 2023 Citations: 1
Fiber-conduit based Laser Speckle Contrast Imaging device for point of care diagnostics R Paul, S Das, S Sarkar, M Zaffar, HM Varma European Conference on Biomedical Optics, 126301A , 2023 2023
Fluorescence scattering in between excitation and emission as a depolarizing process: a Mueller matrix viewpoint M Zaffar Journal of the Optical Society of America A 39 (7), 1179-1186 , 2022 2022 Citations: 3
Spatial autocorrelation analysis on two‐dimensional images of Mueller matrix for diagnosis and differentiation of cervical precancer M Zaffar, A Pradhan Journal of Biophotonics 13 (7), e202000006 , 2020 2020 Citations: 16
Different orders of scattering through time-resolved Mueller matrix imaging estimates of pre-malignancy in human cervical tissues M Zaffar, GR Sahoo, A Pradhan Applied Optics 59 (14), 4286-4295 , 2020 2020 Citations: 13
Mapping of retardance, diattenuation and polarizance vector on Poincare sphere for diagnosis and classification of cervical precancer M Zaffar, A Pradhan Journal of biophotonics 13 (4), e201960139 , 2020 2020 Citations: 26
Assessment of anisotropy of collagen structures through spatial frequencies of Mueller matrix images for cervical pre-cancer detection M Zaffar, A Pradhan Applied Optics 59 (4), 1237-1248 , 2020 2020 Citations: 53
Spatial autocorrelation of Mueller matrix images as indicator of cervical pre-cancer detection M Zaffar, A Pradhan Optics in Health Care and Biomedical Optics VIII 10820, 338-345 , 2018 2018 Citations: 3
Fluorescence spectroscopy for throat cancer detection using human saliva P Kumar, A Singh, M Zaffar, A Pradhan Optical Biopsy XVI: Toward Real-Time Spectroscopic Imaging and Diagnosis … , 2018 2018
Application of wavelet based MFDFA on Mueller matrix images for cervical pre-cancer detection M Zaffar, A Pradhan Optical Biopsy XVI: Toward Real-Time Spectroscopic Imaging and Diagnosis … , 2018 2018 Citations: 1
Application of wavelet based MFDFA on Mueller matrix images for cervical pre-cancer detection A Pradhan, M Zaffar Optical Biopsy XVI: Toward Real-Time Spectroscopic Imaging and Diagnosis, 41 , 2018 2018 Citations: 5
Spatial frequency analysis of Mueller matrix images of cervical tissue sections M Zaffar, A Agarwal, K Pandey, A Pradhan International Conference on Fibre Optics and Photonics, W2B. 3 , 2016 2016 Citations: 4
Measurement of microfibril angles in bamboo using Mueller matrix imaging S Mannan, M Zaffar, A Pradhan, S Basu Applied optics 55 (32), 8971-8978 , 2016 2016 Citations: 17
MOST CITED SCHOLAR PUBLICATIONS
Assessment of anisotropy of collagen structures through spatial frequencies of Mueller matrix images for cervical pre-cancer detection M Zaffar, A Pradhan Applied Optics 59 (4), 1237-1248 , 2020 2020 Citations: 53
Mapping of retardance, diattenuation and polarizance vector on Poincare sphere for diagnosis and classification of cervical precancer M Zaffar, A Pradhan Journal of biophotonics 13 (4), e201960139 , 2020 2020 Citations: 26
Measurement of microfibril angles in bamboo using Mueller matrix imaging S Mannan, M Zaffar, A Pradhan, S Basu Applied optics 55 (32), 8971-8978 , 2016 2016 Citations: 17
Spatial autocorrelation analysis on two‐dimensional images of Mueller matrix for diagnosis and differentiation of cervical precancer M Zaffar, A Pradhan Journal of Biophotonics 13 (7), e202000006 , 2020 2020 Citations: 16
Different orders of scattering through time-resolved Mueller matrix imaging estimates of pre-malignancy in human cervical tissues M Zaffar, GR Sahoo, A Pradhan Applied Optics 59 (14), 4286-4295 , 2020 2020 Citations: 13
Application of wavelet based MFDFA on Mueller matrix images for cervical pre-cancer detection A Pradhan, M Zaffar Optical Biopsy XVI: Toward Real-Time Spectroscopic Imaging and Diagnosis, 41 , 2018 2018 Citations: 5
Spatial frequency analysis of Mueller matrix images of cervical tissue sections M Zaffar, A Agarwal, K Pandey, A Pradhan International Conference on Fibre Optics and Photonics, W2B. 3 , 2016 2016 Citations: 4
Fluorescence scattering in between excitation and emission as a depolarizing process: a Mueller matrix viewpoint M Zaffar Journal of the Optical Society of America A 39 (7), 1179-1186 , 2022 2022 Citations: 3
Spatial autocorrelation of Mueller matrix images as indicator of cervical pre-cancer detection M Zaffar, A Pradhan Optics in Health Care and Biomedical Optics VIII 10820, 338-345 , 2018 2018 Citations: 3
Laser speckle correlation microscopy system to image microvascular perfusion S Sarkar, M Zaffar, HM Varma European Conference on Biomedical Optics, 1262827 , 2023 2023 Citations: 1
Application of wavelet based MFDFA on Mueller matrix images for cervical pre-cancer detection M Zaffar, A Pradhan Optical Biopsy XVI: Toward Real-Time Spectroscopic Imaging and Diagnosis … , 2018 2018 Citations: 1
A POINT-OF-CARE DIAGNOSTIC SYSTEM BASED ON LASER SPECKLE CONTRAST IMAGING (LSCI) USING AN IMAGE CONDUIT Ria PAUL, Susweta DAS, Soumyajit SARKAR, Mohammad ZAFFAR, Hari M VARMA IN Patent 568,348 , 2025 2025
Fluorescence scattering under the Stokes–Mueller formalism determines the orientational distribution of fluorophores and the nature of optically active biological proteins M Zaffar Journal of Optics 26 (12), 125301 , 2024 2024
Fiber-conduit based Laser Speckle Contrast Imaging device for point of care diagnostics R Paul, S Das, S Sarkar, M Zaffar, HM Varma European Conference on Biomedical Optics, 126301A , 2023 2023
Fluorescence spectroscopy for throat cancer detection using human saliva P Kumar, A Singh, M Zaffar, A Pradhan Optical Biopsy XVI: Toward Real-Time Spectroscopic Imaging and Diagnosis … , 2018 2018
