Abstract-Terahertz Single-Pixel Imaging Improved by Using Silicon Wafer with SiO2 Passivation

Rongbin She, Wenquan Liu, Guanglu Wei, Yuanfu Lu, Guangyuan Li

https://www.mdpi.com/2076-3417/10/7/2427

We demonstrate terahertz single-pixel imaging is improved by using a photomodulator based on silicon passivated with SiO 2$$ . By exploring various SiO 2$$ thicknesses, we show that the modulation factor of the as-fabricated terahertz photomodulator can reach 0.9, three times that based on bare silicon. This improvement originates from chemical passivation, as well as anti-reflection. Single-pixel imaging experiments based on the compressed sensing method show that reconstructed images adopting the new photomodulator have better quality than the conventional terahertz modulator based on bare silicon. Since the passivation process is routine and low cost, we expect this work will reduce the cost of terahertz photomodulator and single-pixel THz imaging, and advance their applications.

Abstract-Thermal Analysis of Cornea Heated with Terahertz Radiation

Wenquan Liu, Yuanfu Lu,  Rongbin She, Guanglu Wei, Guohua Jiao,  Jiancheng Lv, Guangyuan Li

https://www.mdpi.com/2076-3417/9/5/917

We numerically investigate the thermal effects in a cornea illuminated by terahertz radiation. By modifying the bioheat and Arrhenius equations, we studied the heat-transfer and temperature distributions in the corneal tissue, and evaluated the potential thermal damage. The influence of the beam radius and power density are discussed. We also estimated the effective cornea-collagen shrinkage region, and evaluated the degree of thermal damage in the cornea. We expect this work to open up a novel effective and safe thermal-treatment approach based on THz radiation for cornea reshaping in the field of ophthalmology

Abstract-Single-pixel terahertz imaging based on spatial Fourier spectrum

Rongbin She, Wenquan Liu, Yuanfu Lu, Zhisheng Zhou, Guangyuan Li

http://export.arxiv.org/abs/1812.06767

We propose and demonstrate single-pixel terahertz imaging based on spatial Fourier spectrum (SFS). The concept and the operation principle of this novel approach are introduced by comparing with the conventional compressing sensing (CS) approach, clarifying their similarities and differences. By doing this, we find that these two different approaches can share the same photo-induced coded aperture setup, facilitating their direct comparisons. Our results show that, compared with the CS approach, the SFS approach can reconstruct high-quality images with greatly reduced number of measurements, i.e., the sampling ratio, and is thus more efficient. Remarkably, the SFS-based system is capable to assemble a 64x64 image with signal-to-noise ratio of 6.0 for a sampling ratio of only 4.8%. We further show that deep photo-induced terahertz modulation by adopting graphene on silicon substrate and high laser power can significantly improve the image quality. We expect this work will speed up the efficiency of single-pixel THz imaging and advance THz imaging applications.