Since the invention of Zernike phase contrast method in 1930,it has been widely used in optical microscopy and more recently in X-ray microscopy.Considering the image contrast is a mixture of absorption and phase info...Since the invention of Zernike phase contrast method in 1930,it has been widely used in optical microscopy and more recently in X-ray microscopy.Considering the image contrast is a mixture of absorption and phase information,we recently have proposed and demonstrated a method for quantitative phase retrieval in Zernike phase contrast X-ray microscopy.In this contribution,we analyze the performance of this method at different photon energies.Intensity images of PMMA samples are simulated at 2.5 keV and 6.2 keV,respectively,and phase retrieval is performed using the proposed method.The results demonstrate that the proposed phase retrieval method is applicable over a wide energy range.For weakly absorbing features,the optimal photon energy is 2.5 keV,from the point of view of image contrast and accuracy of phase retrieval.On the other hand,in the case of strong absorption objects,a higher photon energy is preferred to reduce the error of phase retrieval.These results can be used as guidelines to perform quantitative phase retrieval in Zernike phase contrast X-ray microscopy with the proposed method.展开更多
A new optical microscopy technique,termed high spatial and temporal resolution synthetic aperture phase microscopy(HISTR-SAPM),is proposed to improve the lateral resolution of wide-field coherent imaging.Under plane w...A new optical microscopy technique,termed high spatial and temporal resolution synthetic aperture phase microscopy(HISTR-SAPM),is proposed to improve the lateral resolution of wide-field coherent imaging.Under plane wave illumination,the resolution is increased by twofold to around 260 nm,while achieving millisecond-level temporal resolution.In HISTR-SAPM,digital micromirror devices are used to actively change the sample illumination beam angle at high speed with high stability.An off-axis interferometer is used to measure the sample scattered complex fields,which are then processed to reconstruct high-resolution phase images.Using HISTR-SAPM,we are able to map the height profiles of subwavelength photonic structures and resolve the period structures that have 198 nm linewidth and 132 nm gap(i.e.,a full pitch of 330 nm).As the reconstruction averages out laser speckle noise while maintaining high temporal resolution,HISTR-SAPM further enables imaging and quantification of nanoscale dynamics of live cells,such as red blood cell membrane fluctuations and subcellular structure dynamics within nucleated cells.We envision that HISTR-SAPM will broadly benefit research in material science and biology.展开更多
基金Supported by the State Key Project for Fundamental Research(2012CB825801)National Natural Science Foundation of China(11475170,11205157 and 11179004)Anhui Provincial Natural Science Foundation(1508085MA20)
文摘Since the invention of Zernike phase contrast method in 1930,it has been widely used in optical microscopy and more recently in X-ray microscopy.Considering the image contrast is a mixture of absorption and phase information,we recently have proposed and demonstrated a method for quantitative phase retrieval in Zernike phase contrast X-ray microscopy.In this contribution,we analyze the performance of this method at different photon energies.Intensity images of PMMA samples are simulated at 2.5 keV and 6.2 keV,respectively,and phase retrieval is performed using the proposed method.The results demonstrate that the proposed phase retrieval method is applicable over a wide energy range.For weakly absorbing features,the optimal photon energy is 2.5 keV,from the point of view of image contrast and accuracy of phase retrieval.On the other hand,in the case of strong absorption objects,a higher photon energy is preferred to reduce the error of phase retrieval.These results can be used as guidelines to perform quantitative phase retrieval in Zernike phase contrast X-ray microscopy with the proposed method.
基金We acknowledge financial support from Hong Kong Innovation and Technology Fund(Nos.ITS/394/17 and ITS/098/18FP)Shun Hing Institute of Advanced Engineering(No.BME-p3-18)Croucher Innovation Awards 2019,and the U.S.National Institutes of Health(No.5P41EB015871-33).
文摘A new optical microscopy technique,termed high spatial and temporal resolution synthetic aperture phase microscopy(HISTR-SAPM),is proposed to improve the lateral resolution of wide-field coherent imaging.Under plane wave illumination,the resolution is increased by twofold to around 260 nm,while achieving millisecond-level temporal resolution.In HISTR-SAPM,digital micromirror devices are used to actively change the sample illumination beam angle at high speed with high stability.An off-axis interferometer is used to measure the sample scattered complex fields,which are then processed to reconstruct high-resolution phase images.Using HISTR-SAPM,we are able to map the height profiles of subwavelength photonic structures and resolve the period structures that have 198 nm linewidth and 132 nm gap(i.e.,a full pitch of 330 nm).As the reconstruction averages out laser speckle noise while maintaining high temporal resolution,HISTR-SAPM further enables imaging and quantification of nanoscale dynamics of live cells,such as red blood cell membrane fluctuations and subcellular structure dynamics within nucleated cells.We envision that HISTR-SAPM will broadly benefit research in material science and biology.