BACKGROUND Hepatocellular carcinoma(HCC) is one of the most common malignant tumors worldwide, and novel methods for early/rapid diagnosis of HCC are needed.Terahertz(THz) spectroscopy is considered to have the potent...BACKGROUND Hepatocellular carcinoma(HCC) is one of the most common malignant tumors worldwide, and novel methods for early/rapid diagnosis of HCC are needed.Terahertz(THz) spectroscopy is considered to have the potential to distinguish between normal liver tissue and HCC tissue; however, there are few reports on it.We conduct this observational study to explore the feasibility of THz imaging for the diagnosis of HCC.AIM To evaluate the feasibility of THz for discriminating between HCC and normal liver tissues using fresh tissue specimens obtained from HCC patients who had undergone surgery.METHODS Normal liver tissue and HCC tissue were cryosectioned into 50 μm-thick slicesand placed on cover glass. Two adjacent tissue sections were separated subjected to histopathological examination by hematoxylin and eosin staining or THz transmission examination, and THz images were compared with pathologically mapped images. We determined the typical tumor and normal liver tissue regions by pathological examination; the corresponding areas of adjacent sections were examined by THz transmission.RESULTS The transmission rate of HCC tissue was 0.15-0.25, and the transmission rate of typical HCC tissue was about 0.2. THz transmittance in normal liver tissue is slightly higher than 0.4, but there were many influencing factors, including the degree of liver cirrhosis, fat components, ice crystals in frozen sections, and apoptosis.CONCLUSION In conclusion, this study shows that THz imaging can detect HCC tissue. Further research will yield more detailed data of the THz transmission rates of HCC tissue with different degrees of differentiation.展开更多
For multi-photon processed with the linear dispersion in the high-intensity terahertz(THz) field,we have systematically investigated the temperature-dependent nonlinear optical response of graphene-based systems, incl...For multi-photon processed with the linear dispersion in the high-intensity terahertz(THz) field,we have systematically investigated the temperature-dependent nonlinear optical response of graphene-based systems, including single layer graphene, graphene superlattice and gapped graphene. In the intrinsic single layer graphene system, it demonstrates that, at low temperature, nonlinear optical conductivities of the thirdand fifth-order are respectively five and ten orders of magnitude larger than the universal conductivity with high-intensity and low frequency THz wave.In the graphene superlattice and gapped graphene systems, the optical responses enhanced because of the anisotropic massless and massive Dirac fermions.展开更多
Terahertz wave is between microwave and infrared bands in the electromagnetic spectrum with the frequency range from 0.1 THz to 10 THz. Controlling and processing of the polarization state in terahertz wave are the fo...Terahertz wave is between microwave and infrared bands in the electromagnetic spectrum with the frequency range from 0.1 THz to 10 THz. Controlling and processing of the polarization state in terahertz wave are the focus due to its great influence on the characteristics. In this paper, a transmissive metasurface terahertz polarization converter is designed in 3D structure with an upper surface of ruler-like rectangular, an intermediate dielectric layer and a lower surface of metal grid wires. Numerical simulations of the converter show that the polarization conversion ratio(PCR) is above 99.9% at 0.288 THz–1.6 THz, the polarization rotation angle(PRA) is close to 90° at 0.06 THz–1.4 THz, and the ellipticity angle(EA) is close to 0° at 0.531 THz–1.49 THz. The origin of the efficient polarization conversion is explained by analyzing the electric field intensity, magnetic field intensity, surface current, electric field energy density, and magnetic field energy density distributions of the converter at 1.19 THz and 0.87 THz, which are consistent with the energy transmittance and transmittance coefficient. In addition, the effects of different thickness and material of intermediate layer, thickness of upper surface material, polarized wave incidence angle, and metasurface materials on the performance of the polarization converter are discussed, and how they affect the conversion performance of the polarization converter are also explained.Our results provide a strong theoretical basis and technical support to develop high performance transmission-type terahertz polarization converters, and play an important role to promote the development of terahertz science and technology.展开更多
二氧化钒(VO2)是一种具有可逆热致相变性质的材料,在太赫兹调制领域具有应用潜力。为了确认VO2复合薄膜对太赫兹调控的可行性,在进行相关实验之前,首先运用CST Studio Suite电磁仿真软件进行模拟研究,主要探究了VO2及其与金属光栅结合...二氧化钒(VO2)是一种具有可逆热致相变性质的材料,在太赫兹调制领域具有应用潜力。为了确认VO2复合薄膜对太赫兹调控的可行性,在进行相关实验之前,首先运用CST Studio Suite电磁仿真软件进行模拟研究,主要探究了VO2及其与金属光栅结合的复合薄膜的相关参数对太赫兹透射及调控的影响。仿真结果表明,VO2能很好地调控太赫兹的透射幅度,调控深度可由相变幅度控制。另外仿真发现,对VO2复合薄膜而言,通过控制光栅的参数变化可以改变太赫兹透射幅度,并且可以通过调控光栅周期实现对太赫兹调制深度控制。展开更多
基金Supported by the National Natural Science Foundation of China,No.11622542 and No.51677145
文摘BACKGROUND Hepatocellular carcinoma(HCC) is one of the most common malignant tumors worldwide, and novel methods for early/rapid diagnosis of HCC are needed.Terahertz(THz) spectroscopy is considered to have the potential to distinguish between normal liver tissue and HCC tissue; however, there are few reports on it.We conduct this observational study to explore the feasibility of THz imaging for the diagnosis of HCC.AIM To evaluate the feasibility of THz for discriminating between HCC and normal liver tissues using fresh tissue specimens obtained from HCC patients who had undergone surgery.METHODS Normal liver tissue and HCC tissue were cryosectioned into 50 μm-thick slicesand placed on cover glass. Two adjacent tissue sections were separated subjected to histopathological examination by hematoxylin and eosin staining or THz transmission examination, and THz images were compared with pathologically mapped images. We determined the typical tumor and normal liver tissue regions by pathological examination; the corresponding areas of adjacent sections were examined by THz transmission.RESULTS The transmission rate of HCC tissue was 0.15-0.25, and the transmission rate of typical HCC tissue was about 0.2. THz transmittance in normal liver tissue is slightly higher than 0.4, but there were many influencing factors, including the degree of liver cirrhosis, fat components, ice crystals in frozen sections, and apoptosis.CONCLUSION In conclusion, this study shows that THz imaging can detect HCC tissue. Further research will yield more detailed data of the THz transmission rates of HCC tissue with different degrees of differentiation.
基金supported by the National Special Fund for the Development of Major Research Equipment and Instruments (project No. 2011YQ13001805)the Foundation of Beijing Educational Commission, China(Grant No. KM201010028006)
文摘For multi-photon processed with the linear dispersion in the high-intensity terahertz(THz) field,we have systematically investigated the temperature-dependent nonlinear optical response of graphene-based systems, including single layer graphene, graphene superlattice and gapped graphene. In the intrinsic single layer graphene system, it demonstrates that, at low temperature, nonlinear optical conductivities of the thirdand fifth-order are respectively five and ten orders of magnitude larger than the universal conductivity with high-intensity and low frequency THz wave.In the graphene superlattice and gapped graphene systems, the optical responses enhanced because of the anisotropic massless and massive Dirac fermions.
文摘在太赫兹通信等系统中需要利用太赫兹波调制器对信号进行调制。基于Ga As等传统半导体材料设计和制作的调制器在太赫兹波段的响应过低,因而很难应用于太赫兹系统。为了弥补传统调制技术在带宽和调制深度不够的缺点,设计了一种全新的基于硅基石墨烯的全光控太赫兹强度调制系统。该调制系统利用材料中光生载流子对太赫兹波的吸收特性,通过调节照射到材料上的可见光光强来改变光生载流子浓度,从而实现对太赫兹波强度调制。从理论和实验两方面对这种新型太赫兹强度调制系统的调制深度和调制带宽进行了研究。研究结果表明,在泵浦光功率密度为18 m W/mm2时,该调制系统能在实验使用的THz-TDS测试系统（0.1~2.5 THz）的整个频谱范围内进行有效的调制,调制深度可达到12%。且随着泵浦光能量的增大,调制深度增大。
基金supported by the National Natural Science Fundation (Grant Nos. 12134016 and 61625505)Chinese Academy of Sciences (Grant No. ZDBS-LY-JSC025)+1 种基金Sino– Russia International Joint Laboratory of Terahertz Materials and Devices (Grant No. 18590750500)Shanghai Municipal Science and Technology Major Project (Grant No. 2019SHZDZX01)。
文摘Terahertz wave is between microwave and infrared bands in the electromagnetic spectrum with the frequency range from 0.1 THz to 10 THz. Controlling and processing of the polarization state in terahertz wave are the focus due to its great influence on the characteristics. In this paper, a transmissive metasurface terahertz polarization converter is designed in 3D structure with an upper surface of ruler-like rectangular, an intermediate dielectric layer and a lower surface of metal grid wires. Numerical simulations of the converter show that the polarization conversion ratio(PCR) is above 99.9% at 0.288 THz–1.6 THz, the polarization rotation angle(PRA) is close to 90° at 0.06 THz–1.4 THz, and the ellipticity angle(EA) is close to 0° at 0.531 THz–1.49 THz. The origin of the efficient polarization conversion is explained by analyzing the electric field intensity, magnetic field intensity, surface current, electric field energy density, and magnetic field energy density distributions of the converter at 1.19 THz and 0.87 THz, which are consistent with the energy transmittance and transmittance coefficient. In addition, the effects of different thickness and material of intermediate layer, thickness of upper surface material, polarized wave incidence angle, and metasurface materials on the performance of the polarization converter are discussed, and how they affect the conversion performance of the polarization converter are also explained.Our results provide a strong theoretical basis and technical support to develop high performance transmission-type terahertz polarization converters, and play an important role to promote the development of terahertz science and technology.
文摘二氧化钒(VO2)是一种具有可逆热致相变性质的材料,在太赫兹调制领域具有应用潜力。为了确认VO2复合薄膜对太赫兹调控的可行性,在进行相关实验之前,首先运用CST Studio Suite电磁仿真软件进行模拟研究,主要探究了VO2及其与金属光栅结合的复合薄膜的相关参数对太赫兹透射及调控的影响。仿真结果表明,VO2能很好地调控太赫兹的透射幅度,调控深度可由相变幅度控制。另外仿真发现,对VO2复合薄膜而言,通过控制光栅的参数变化可以改变太赫兹透射幅度,并且可以通过调控光栅周期实现对太赫兹调制深度控制。
