Category: Closed for Student Enrollment

Project supervisor: Yoav Hazan

yoav.hazan@campus.technion.ac.il

In the development of Electro-Optic Modulated Pulse Interferometry (EOM-PI) emerged the need for the development of a technique for sampling the EOM-PI signal with low bandwidth sampler (~10MHz) rather than the 1.5GHz sampling bandwidth implemented today. Furthermore, a development of demodulation algorithm for the sampled signals to retrieve signal’s phase.

Project Status: Finished

Project requirements:

1. Development of signal analysis process to achieve 2-channel sampling of low bandwidth of ~10MHz from a 1-channel 1.5GHz original signal. The two sampling channels are in the surrounding of the DC and the EOM frequency (125MHz).
2. Development of signal demodulation algorithm to retrieve the signal’s phase from the 2-channel sampling, where the two signals will be in the form of: and .  The demodulation algorithm should be able to handle either DC-coupled measurement and AC-couple measurement.

Advancement options:

1. Designing an electrical circuit that will operate as developed in the first project requirement.

Recommended readings:

1. Hazan, Yoav, and Amir Rosenthal. “Passive-demodulation pulse interferometry for ultrasound detection with a high dynamic range.” Optics letters5 (2018): 1039-1042.
2. Rosenthal, Amir, Daniel Razansky, and Vasilis Ntziachristos. “Wideband optical sensing using pulse interferometry.” Optics Express17 (2012): 19016-19029.

Project supervisor: Yoav Hazan

yoav.hazan@campus.technion.ac.il

Laser Speckle Contrast Imaging (LSCI) is an imaging method used in diffusive media. This method maps the regions of dynamic scatters, i.e. blood flowing in blood vessels. Due to developments in both cameras and miniaturized computers, LSCI systems may be implemented in a small cost efficient system, such as a RaspberryPi platform.

Project Status: Taken

Raw image of part of a rat cortex (a) and its LSCI version (b). Briers et al., 2013

Project requirements:

1. Implementing stand-alone LSCI system on a RaspberryPi platform.
2. Researching LSCI from high frame rate video. Theoretical analysis and modeling of the new measured field mapped by high frame rate LSCI.

Advancement options:

1. Researching bi-spectral LSCI.

Recommended readings:

1. Richards, Lisa M., SM Shams Kazmi, Janel L. Davis, Katherine E. Olin, and Andrew K. Dunn. “Low-cost laser speckle contrast imaging of blood flow using a webcam.” Biomedical optics express, vol. 4, no. 10 (2013): 2269-2283.
2. Briers, David, Donald D. Duncan, Evan R. Hirst, Sean J. Kirkpatrick, Marcus Larsson, Wiendelt Steenbergen, Tomas Stromberg, and Oliver B. Thompson. “Laser speckle contrast imaging: theoretical and practical limitations.” Journal of biomedical optics, vol. 18, no. 6 (2013): 066018.
3. Boas, David A., and Andrew K. Dunn. “Laser speckle contrast imaging in biomedical optics.” Journal of biomedical optics, vol. 15, no. 1 (2010): 011109.

Project supervisor: Yoav Hazan

yoav.hazan@campus.technion.ac.il

Optical detection of ultrasound is mostly done with high-Q factor optical resonators. These optical resonators can be manufactured in Silicon wafers, where the resonators spectra are highly sensitive to the polarization state of the propagating beam. TM polarized beam can potentially increase manufacturing yield as well as sensing sensitivity by an order of magnitude.

Project Status: Available

Project requirements:

1. Simulations comparing TE and TM beam propagations through phase-shifted Bragg grating resonators in Silicon waveguide.
2. Optimization of waveguide dimensions for narrow resonance and high transmission efficiency.

Advancement options:

1. Simulations of different resonator structures, and the sensitivity for the two difference polarization states.

Recommended readings:

1. Painchaud, Y., Poulin, M., Latrasse, C., Ayotte, N., Picard, M.J. and Morin, M., 2012, June. “Bragg grating notch filters in silicon-on-insulator waveguides”. In Bragg Gratings, Photosensitivity, and Poling in Glass Waveguides (pp. BW2E-3). Optical Society of America.