Showing posts with label Lei Yang. Show all posts
Showing posts with label Lei Yang. Show all posts

Tuesday, September 8, 2020

Abstract-Detection of Living Cervical Cancer Cells by Transient Terahertz Spectroscopy


Wei Shi, Yuezheng Wang, Lei Hou, Cheng Ma, Lei Yang, Chengang Dong, Zhiquan Wang, Haiqing Wang, Juan Guo, Shenglong Xu  Jing Li,

https://onlinelibrary.wiley.com/doi/abs/10.1002/jbio.202000237

The photonic energy of terahertz wave is in the same order of magnitude as the rotational and vibrational energy levels of organic and biological macro‐molecules, so it has unique advantages in detecting cells and biological macro‐molecules. However, in the life environment, the dynamic time scale of cell‐environment interaction and structural conformation change of biological macro‐molecules are within picosecond to millisecond, and water has strong absorption to terahertz wave, which has become the bottleneck problem for the detection of cells and biological macro‐molecules by terahertz technology. In this paper, we developed a set of terahertz single measurement system based on the tilt wave front of grating pulse technique. The system was employed for the terahertz detection of trace living cervical cancer cells. We achieved transient detection of the terahertz pulse time domain waveform of the living HeLa cells. The characteristic absorption peaks were identified by Lambert‐Beer law, respectively at 0.49 THz, 0.71 THz, 1.04 THz, 1.07 THz, 1.26 THz and1.37 THz. The absorbance is proportional to the cell concentration.
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Saturday, June 3, 2017

Abstract-Terahertz Real-Time Off-Axis Digital Holography with Zoom Function


 and 

http://iopscience.iop.org/article/10.1088/0256-307X/34/5/054207/meta;jsessionid=3E8C126700C724792F9F7ED8AAB28723.c1.iopscience.cld.iop.org

We present a terahertz (THz) real-time digital holographic system with zoom function worked at 0.17 THz. The magnification factor ranges from 1 to 2. In the imaging experiment, the resolution is 2 mm with the magnification factor of 1.2. A metal sheet with F-shaped hollow is used as a sample, and its THz holograms are reconstructed by our developed algorithm based on the angular spectrum theorem, and the qualities of the THz images under different conditions are compared.

Wednesday, May 10, 2017

Abstract-Terahertz artificial birefringence and tunable phase shifter based on dielectric metasurface with compound lattice


Yun-Yun Ji, Fei Fan, Meng Chen, Lei Yang, and Sheng-Jiang Chang

https://www.osapublishing.org/oe/abstract.cfm?uri=oe-25-10-11405

A dielectric metasurface with line-square compound lattice structure has been fabricated and demonstrated in the terahertz (THz) regime by the THz time-domain spectroscopy and numerical simulation. A polarization dependent electromagnetically induced transparency (EIT) effect is achieved in this metasurface due to the mode coupling and interference between the resonance modes in line and square subunits of the metasurface. Accompany with the EIT effect, a large artificial birefringence effect between two orthogonal polarization states is also observed in this compound metasurface, of which birefringence is over 0.6. Furthermore, the liquid crystals are filled on the surface of this dielectric metasurface to fabricate an electrically tunable THz LC phase shifter. The experimental results show that its tunable phase shift under the biased electric field reaches 0.33π, 1.8 times higher than the bare silicon, which confirms the enhancement role of THz microstructure on the LC phase shift in the THz regime. The large birefringence phase shift of this compound metasurface and its LC tunable phase shifter will be of great significance for potential applications in THz polarization and phase devices.
© 2017 Optical Society of America