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High space-bandwidth product with high spatial phase sensitivity is indispensable for a single-shot quantitative phase microscopy (QPM) system. It opens avenue for widespread applications of QPM in the field of biomedical imaging. Temporally low coherence length light sources are generally implemented to achieve high spatial phase sensitivity in QPM at the cost of either reduced temporal resolution or smaller field of view (FOV). On the contrary, high temporal coherence light sources like lasers are capable of exploiting the full FOV of the QPM systems at the expense of less spatial phase sensitivity. In the present work, we employed pseudo-thermal light source (PTLS) in QPM which overcomes the limitations of conventional light sources. The capabilities of PTLS over conventional light sources are systematically studied and demonstrated on various test objects like USAF resolution chart and thin optical waveguide (height ~ 8 nm). The spatial phase sensitivity of QPM in case of PTLS is measured to be equivalent to that for white light source. The high-speed and large FOV capabilities of PTLS based QPM is demonstrated by high-speed imaging of live sperm cells that is limited by the camera speed and by imaging extra-ordinary large FOV phase imaging on histopathology placenta tissue samples., Comment: 15 pages, 7 figures

Sperm cell motility and morphology observed under the bright field microscopy are the only criteria for selecting particular sperm cell during Intracytoplasmic Sperm Injection (ICSI) procedure of Assisted Reproductive Technology (ART). Several factors such as, oxidative stress, cryopreservation, heat, smoking and alcohol consumption, are negatively associated with the quality of sperm cell and fertilization potential due to the changing of sub-cellular structures and functions which are overlooked. A bright field imaging contrast is insufficient to distinguish tiniest morphological cell features that might influence the fertilizing ability of sperm cell. We developed a partially spatially coherent digital holographic microscope (PSC-DHM) for quantitative phase imaging (QPI) in order to distinguish normal sperm cells from sperm cells under different stress conditions such as cryopreservation, exposure to hydrogen peroxide and ethanol without any labeling. Phase maps of 10,163 sperm cells (2,400 control cells, 2,750 spermatozoa after cryopreservation, 2,515 and 2,498 cells under hydrogen peroxide and ethanol respectively) are reconstructed using the data acquired from PSC-DHM system. Total of seven feedforward deep neural networks (DNN) were employed for the classification of the phase maps for normal and stress affected sperm cells. When validated against the test dataset, the DNN provided an average sensitivity, specificity and accuracy of 84.88%, 95.03% and 85%, respectively. The current approach DNN and QPI techniques of quantitative information can be applied for further improving ICSI procedure and the diagnostic efficiency for the classification of semen quality in regards to their fertilization potential and other biomedical applications in general.