Hongchang Wang

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Hongchang Wang is a Senior Optics Scientist in the Optics and Metrology Group.  Hongchang joined Diamond in March 2009 after working for the University College London.

Email: hongchang.wang@diamond.ac.uk
Tel: +44 (0) 1235 778754

Key Research Area

Latest Publications

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  1. Research Expertise
  2. Publications
Research Expertise -

Research Expertise

Soft X-ray Polarimetry, At-wavelength Metrology of X-ray Optics, X-ray Imaging.

X-ray optics, including mirrors, Fresnel zone plates and compound refractive lenses, play an important role for micro- or nano-focusing in synchrotron radiation experiments. However, the push toward high resolution and sensitivity on the nanometer scale to create diffraction-limited and coherence-preserved beams requires further development of X-ray optics. This in turn demands more accurate metrology. The ultimate measure of an X-ray optic’s performance is when it’s installed on the beamline. The best pathway to overcome these limitations, and help to improve the present performance of X-ray optics, is using at-wavelength (performed with X-rays) and in-situ (performed in a beamline environment) techniques.

We have implemented and further developed X-ray grating based and speckle based techniques at the Diamond Test beamline B16. Both techniques have been used in the X-ray phase contrast and dark field imaging, in-situ characterization and optimization of X-ray optics.

Polarized soft x-rays have played an important role in the investigation of magnetic materials containing 3d transition metals and rare earth-elements. Knowledge of the degree of polarization is essential, not only for understanding the undulator performance, but also to carry out a precise analysis of dichroic and chiral experiments. A high-precision polarimeter has been designed and built by Diamond scientists along with colleagues from STFC. This flexible polarimeter has been routinely used for the polarization measurement among the soft X-ray beamlines at Diamond.

  • Work in the optical design and commissioning of beamlines, especially in the soft X-ray regime, working in close collaboration with beamline scientists;
  • Support beamline scientists in specifying, procuring and testing of beamline optics;
  • Undertake research in the field of at-wavelength metrology, X-ray Imaging and soft x-ray polarimetry.

 

Publications - +

Publications

  • Wang H, Kashyap Y, Sawhney K. From synchrotron radiation to lab source: advanced speckle-based X-ray imaging using abrasive paper. Scientific Reports 2016, 6: 20476.
     
  • Wang H, Kashyap Y, Sawhney K. Hard-X-Ray Directional Dark-Field Imaging Using the Speckle Scanning Technique. Phys. Rev. Lett. 2015, 114(10): 103901.
     
  • Wang H, Berujon S, Herzen J, Atwood R, Laundy D, Hipp A, Sawhney K. X-ray phase contrast tomography by tracking near field speckle. Scientific Reports 2015, 5: 8762.
     
  • Wang H, Sutter J, Sawhney K. Advanced in situ metrology for x-ray beam shaping with super precision. Opt Express 2015, 23(2): 1605-1614.
     
  • Wang H, Kashyap Y, Sawhney K. Speckle based X-ray wavefront sensing with nanoradian angular sensitivity. Opt Express 2015, 23(18): 23310-23317.
     
  • Wang H, Kashyap Y, Laundy D, Sawhney K. Two-dimensional in situ metrology of X-ray mirrors using the speckle scanning technique. J Synchrotron Rad 2015, 22(4): 925-929.
     
  • Kashyap Y, Wang H, Sawhney K. Two-dimensional transverse coherence measurement of hard-x-ray beams using near-field speckle. Phys Rev A 2015, 92(3): 033842.
     
  • Wang H, Sawhney K, Berujon S, Sutter J, Alcock SG, Wagner U, et al. Fast optimization of a bimorph mirror using x-ray grating interferometry. Opt Lett 2014, 39(8): 2518-2521.
     
  • Berujon S, Wang H, Alcock S, Sawhney K. At-wavelength metrology of hard X-ray mirror using near field speckle. Opt Express 2014, 22(6): 6438-6446.
     
  • Wang H, Berujon S, Pape I, Rutishauser S, David C, Sawhney K. X-ray wavefront characterization of a Fresnel zone plate using a two-dimensional grating interferometer. Opt Lett 2013, 38(6): 827-829.
     
  • Berujon S, Wang H, Pape I, Sawhney K. X-ray phase microscopy using the speckle tracking technique. Appl Phys Lett 2013, 102(15): 154105-154104.
     
  • Berujon S, Wang H, Sawhney K. X-ray multimodal imaging using a random-phase object. Phys Rev A 2012, 86(6): 063813.
     
  • Berujon S, Wang H, Pape I, Sawhney K, Rutishauser S, David C. X-ray submicrometer phase contrast imaging with a Fresnel zone plate and a two dimensional grating interferometer. Opt Lett 2012, 37(10): 1622-1624.
     
  • Wang H, Sawhney K, Berujon S, Ziegler E, Rutishauser S, David C. X-ray wavefront characterization using a rotating shearing interferometer technique. Opt Express 2011, 19(17): 16550-16559.
     
  • Wang H, Dhesi SS, Maccherozzi F, Sawhney KJS. Complete polarization analysis of high energy soft x-rays by combining a multilayer phase retarder with crystal analyzer. Journal of Applied Physics 2012, 111(12): 123117-123114.
     
  • Wang H, Bencok P, Steadman P, Longhi E, Zhu J, Wang Z. Complete polarization analysis of an APPLE II undulator using a soft X-ray polarimeter. Journal of Synchrotron Radiation 2012, 19(6): 944-948.
  • Wang H, Dhesi SS, Maccherozzi F, Cavill S, Shepherd E, Yuan F, et al. High-precision soft x-ray polarimeter at Diamond Light Source. Review of Scientific Instruments 2011, 82(12): 123301-123306.