Biophotonics Laboratory
California Institute of Technology


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Jigang WuJigang Wu


PhD, Electrical Engineering, California Institute of Technology, 2008
MS, Electrical Engineering, California Institute of Technology, 2005
MS, Physics, Tsinghua University, China, 2004
BS, Physics, Tsinghua University, China, 2001

Research Interests

Current Research

While at Caltech, I worked on a novel wide-field microscope scheme based on holography and microfabrication techniques. Compared with conventional microscopes, which have a limited field-of-view, this new scheme in principle can achieve an arbitrary field-of-view.

Previous Research Projects

1. Paired-angle Rotation Scanning OCT (PARS-OCT) Probe
This probe design utilizes a pair of angle-cut rotating GRIN lenses to deflect and scan the OCT probe beam across the forward region ahead of the probe tip. In this design, the scan actuation system may be located away from the probe tip, much like in the case of a side-imaging OCT probe, enabling easy miniaturization of the actual probe. By controlling the rotation of the two needles that hold the GRIN lenses, different volumetric scanning schemes can be achieved. A prototype probe has been built to demonstrate our idea. Currently we use tadpoles as our object and we are looking forward to applying the probe to other samples such as animal GI tract etc. The potential application of the PARS-OCT probe is needle guidance in anesthesiology procedure or needle biopsy.

2. Quadrature Phase Microscope based on Harmonically-related Grating Pairs
By recording two harmonically related gratings on the same hologram, we are able to obtain nontrivial phase difference between the output ports of the gratings. The phase difference can be adjusted by changing the relative phase of the recording beams when recording the hologram. We built a Mach-Zehnder interferometer using the holographic gratings as a beam coupler/splitter, and put two CCD cameras in the output ports of the gratings. In this way, we are able to get quadrature full field images in the two cameras and reconstruct the phase image accordingly.

3. The application of Fresnel zone plate based projection in optofluidic microscopy
Optofluidic microscopy (OFM) is a novel technique for lowcost, high-resolution on-chip microscopy imaging. In this project, we use the Fresnel zone plate (FZP) based projection in OFM as a cost-effective and compact means for projecting the transmission through an OFM’s aperture array onto a sensor grid. The imaging quality of the FZP determines the effective field-of-view (related to the number of resolvable transmissions from apertures) but not the image resolution of such an OFM system – a key distinction from conventional FZP based microscope systems.

Peer-Reviewed Publications:

1. Jigang Wu, Xiquan Cui, Lap Man Lee, and Changhuei Yang, The application of Fresnel zone plate based projection in optofluidic microscopy, Optics Express 16, 15595 (2008)

2. Shuo Han, Marinko V. Sarunic, Jigang Wu, Mark Humayun, and Changhuei Yang, Handheld forward-imaging needle endoscope for ophthalmic optical coherence tomography inspection, Journal of Biomedical Optics 13, 020505 (2008)

3. Jigang Wu, Zahid Yaqoob, Xin Heng, Xiquan Cui, and Changhuei Yang, Harmonically matched grating-based full-field quantitative high-resolution phase microscope for observing dynamics of transparent biological samples, Optics Express 15, 18141 (2007)

4. David T. Raphael, Changhuei Yang, Nancy Tresser, Jigang Wu, Yaoping Zhang, and Linda Rever, Images of spinal nerves and adjacent structures with optical coherence tomography: preliminary animal studies, The Journal of Pain 8, 767 (2007)

5. Jigang Wu, Zahid Yaqoob, Xin Heng, Lap Man Lee, Xiquan Cui, and Changhuei Yang, Full field phase imaging using a harmonically matched diffraction grating pair based homodyne quadrature interferometer, Applied Physics Letters 90, 151123 (2007)

6. Zahid Yaqoob, Jigang Wu, Emily J. McDowell, Xin Heng, and Changhuei Yang, Methods and application areas of endoscopic optical coherence tomography, Journal of Biomedical Optics 11, 063001 (2006)

7. Xiquan Cui, Xin Heng, Jigang Wu, Zahid Yaqoob, and Changhuei Yang, Slanted hole array beam profiler (SHArP) -- a high-resolution portable beam profiler based on a linear aperture array, Optics Letters 31, 3161 (2006)

8. Xin Heng, Xiquan Cui, David W. Knapp, Jigang Wu, Zahid Yaqoob, Emily J. McDowell, Demetri Psaltis, and Changhuei Yang, Characterization of light collection through a subwavelength aperture from a point source, Optics Express 14, 10410 (2006)

9. Zahid Yaqoob, Emily McDowell, Jigang Wu, Xin Heng, Jeff Fingler, and Changhuei Yang, Molecular contrast optical coherence tomography: a pump-probe scheme using indocyanine green as a contrast agent, Journal of Biomedical Optics 11, 054017 (2006)

10. Zahid Yaqoob, Jigang Wu, Xiquan Cui, Xin Heng, and Changhuei Yang, Harmonicallyrelated diffraction gratings-based interferometer for quadrature phase measurements, Optics Express 14, 8127 (2006)

11. Jigang Wu, Michael Conry, Chunhui Gu, Fei Wang, Zahid Yaqoob and Changhuei Yang, Paried-angle-rotation scanning optical coherence tomography forward-imaging probe, Optics Letters 31, 1265 (2006)

12. Guanglei Xiong, Ping Xue, Jigang Wu, Qin Miao, Rui Wang, and Liang Ji, Particle-fixed Monte Carlo model for optical coherence tomography, Optics Express 13, 2182 (2005)

13. Tieying Zhou, Kai Zhang, Yu Chen, Huan Wang, Jigang Wu, Kaili Jiang, and Ping Xue, A cylindrical rod ultrasonic motor with 1 mm diameter and its application in endoscopic OCT, Chinese Science Bulletin 50, 826 (2005)

14. Jigang Wu, Ping Xue, Shan Sun, and Jihua Guo, Spectral shaping in rapid scanning optical delay line of optical coherence tomography, Chinese Physics Letters 20, 2172 (2003)