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Article List
2025, 23(2):73-83.
DOI: 10.11805/TKYDA2024326
Abstract:
A terahertz parametric radiation source based on Stimulated Polariton Scattering(SPS) is an optically coherent terahertz source, characterized by high coherence, frequency tunability, and operation at room temperature. The basic principle of terahertz parametric radiation based on SPS, commonly used nonlinear crystals, and coupling techniques are firstly introduced. Then typical techniques and research achievements in recent years, both domestical and international, are summarized regarding gain enhancement and output performance improvement. Additionally, the progress in the application of terahertz radiation sources in material concentration detection is reviewed. Finally, the key technical issues and development trends of terahertz parametric radiation sources are analyzed.
A terahertz parametric radiation source based on Stimulated Polariton Scattering(SPS) is an optically coherent terahertz source, characterized by high coherence, frequency tunability, and operation at room temperature. The basic principle of terahertz parametric radiation based on SPS, commonly used nonlinear crystals, and coupling techniques are firstly introduced. Then typical techniques and research achievements in recent years, both domestical and international, are summarized regarding gain enhancement and output performance improvement. Additionally, the progress in the application of terahertz radiation sources in material concentration detection is reviewed. Finally, the key technical issues and development trends of terahertz parametric radiation sources are analyzed.
2025, 23(2):109-115.
DOI: 10.11805/TKYDA2024546
Abstract:
By revealing the THz spectral characteristics of glioma and contralateral normal brain tissue, and analyzing the spectral differences in tumor space, this study provides theoretical support for non-invasive tumor diagnosis. Using an orthotopic U87 glioma cell tumor-bearing mouse model, terahertz spectroscopy is employed to characterize the absorption properties of the glioma lesion area and the contralateral brain tissue. Single-factor Analysis Of Variance(ANOVA) and Tukey's Honestly Significant Difference(HSD) post hoc test are adopted to assess the significant differences in spectral absorption between different layers of the tumor. Immunofluorescence results show differences in cell proliferation ability and vascular density in the glioma lesion area. THz spectral analysis indicates that above 2 THz, the absorption coefficient of the tumor area is significantly higher than that of normal brain tissue, especially with the peripheral surrounding area (L(6-7)) having a higher absorption coefficient than the tumor enhancement area (L(1-2)). ANOVA analysis confirms that the spectral absorption differences between different layers of the tumor are statistically significant(p<0.05), and Tukey's HSD test further confirms the specific differences between each layer within the tumor. Homogeneity of variance test shows significant heterogeneity within the tumor layers, while the normal brain tissue area exhibits more consistent spectral characteristics. The study demonstrates that terahertz spectroscopy can effectively identify the internal heterogeneity of glioma, especially the absorption differences between the lesion center and the infiltration area, providing important evidence for noninvasive tumor diagnosis and showcasing its application potential.
By revealing the THz spectral characteristics of glioma and contralateral normal brain tissue, and analyzing the spectral differences in tumor space, this study provides theoretical support for non-invasive tumor diagnosis. Using an orthotopic U87 glioma cell tumor-bearing mouse model, terahertz spectroscopy is employed to characterize the absorption properties of the glioma lesion area and the contralateral brain tissue. Single-factor Analysis Of Variance(ANOVA) and Tukey's Honestly Significant Difference(HSD) post hoc test are adopted to assess the significant differences in spectral absorption between different layers of the tumor. Immunofluorescence results show differences in cell proliferation ability and vascular density in the glioma lesion area. THz spectral analysis indicates that above 2 THz, the absorption coefficient of the tumor area is significantly higher than that of normal brain tissue, especially with the peripheral surrounding area (L(6-7)) having a higher absorption coefficient than the tumor enhancement area (L(1-2)). ANOVA analysis confirms that the spectral absorption differences between different layers of the tumor are statistically significant(p<0.05), and Tukey's HSD test further confirms the specific differences between each layer within the tumor. Homogeneity of variance test shows significant heterogeneity within the tumor layers, while the normal brain tissue area exhibits more consistent spectral characteristics. The study demonstrates that terahertz spectroscopy can effectively identify the internal heterogeneity of glioma, especially the absorption differences between the lesion center and the infiltration area, providing important evidence for noninvasive tumor diagnosis and showcasing its application potential.
2025, 23(2):84-95.
DOI: 10.11805/TKYDA2024353
Abstract:
In recent years, terahertz photonics of gases (such as air plasma) has developed rapidly, but there are relatively few research reports on the generation of terahertz waves by liquids, especially liquid water, which exhibits significant absorption performance in the terahertz frequency range, leading researchers to believe that liquids cannot be sources of terahertz waves. Recently, experiments have confirmed that broadband terahertz waves can be generated by exciting liquids with femtosecond lasers, and liquids have unique characteristics as terahertz wave radiation sources. The density of liquids is close to that of solids, and they perform excellently in interactions with laser pulses, with effects far exceeding those of gas sources. The fluidity of gases and liquids ensures that each laser pulse can interact with a new target area, greatly avoiding damage or degradation of the medium, a function that is difficult to achieve with solid materials. It is these unique characteristics that make gases and liquids show great potential in the research of high-energy-density plasmas and the development of next-generation terahertz wave sources. This article reviews the research progress of gases and liquids as broadband terahertz sources and compares various methods of generating terahertz waves using gases and liquids. Terahertz gas and liquid photonics reveal the potential for developing new types of terahertz wave sources and open up new research directions for studying the interactions between lasers and liquids.
In recent years, terahertz photonics of gases (such as air plasma) has developed rapidly, but there are relatively few research reports on the generation of terahertz waves by liquids, especially liquid water, which exhibits significant absorption performance in the terahertz frequency range, leading researchers to believe that liquids cannot be sources of terahertz waves. Recently, experiments have confirmed that broadband terahertz waves can be generated by exciting liquids with femtosecond lasers, and liquids have unique characteristics as terahertz wave radiation sources. The density of liquids is close to that of solids, and they perform excellently in interactions with laser pulses, with effects far exceeding those of gas sources. The fluidity of gases and liquids ensures that each laser pulse can interact with a new target area, greatly avoiding damage or degradation of the medium, a function that is difficult to achieve with solid materials. It is these unique characteristics that make gases and liquids show great potential in the research of high-energy-density plasmas and the development of next-generation terahertz wave sources. This article reviews the research progress of gases and liquids as broadband terahertz sources and compares various methods of generating terahertz waves using gases and liquids. Terahertz gas and liquid photonics reveal the potential for developing new types of terahertz wave sources and open up new research directions for studying the interactions between lasers and liquids.
2025, 23(2):96-101.
DOI: 10.11805/TKYDA2024545
Abstract:
A high-Q all-silicon structured metasurface is proposed, consisting of two layers of silicon square pillars. By adjusting the lateral offset distance between the upper and lower layers in thex ![]()
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A high-Q all-silicon structured metasurface is proposed, consisting of two layers of silicon square pillars. By adjusting the lateral offset distance between the upper and lower layers in the
2025, 23(2):102-108.
DOI: 10.11805/TKYDA2024217
Abstract:
Thermal stability is a key indicator for polymeric materials. Using Terahertz Time-Domain Spectroscopy(THz-TDS) technology combined with a temperature control device, two types of thermoplastic polyurethane elastomers(TPU) solid samples are tested. At room temperature, there are differences in the terahertz absorption coefficients and refractive index values of different types of TPU. During the process of heating from 20 ℃ to 160 ℃, as the temperature increases, the terahertz absorption coefficient gradually increases, while the refractive index decreases. The turning point of the linear fit corresponds to the reported Vicat transition temperature of the material, and the sample with higher thermal stability maintains its optical constants more stable after heating and cooling. The research results indicate that terahertz spectroscopy technology can provide a new approach for detecting the thermal stability of polymeric materials.
Thermal stability is a key indicator for polymeric materials. Using Terahertz Time-Domain Spectroscopy(THz-TDS) technology combined with a temperature control device, two types of thermoplastic polyurethane elastomers(TPU) solid samples are tested. At room temperature, there are differences in the terahertz absorption coefficients and refractive index values of different types of TPU. During the process of heating from 20 ℃ to 160 ℃, as the temperature increases, the terahertz absorption coefficient gradually increases, while the refractive index decreases. The turning point of the linear fit corresponds to the reported Vicat transition temperature of the material, and the sample with higher thermal stability maintains its optical constants more stable after heating and cooling. The research results indicate that terahertz spectroscopy technology can provide a new approach for detecting the thermal stability of polymeric materials.
2025, 23(2):116-122.
DOI: 10.11805/TKYDA2024548
Abstract:
Precise diagnosis and personalized treatment of neurological diseases are crucial for improving patient outcomes. Terahertz(THz) metamaterials, due to their unique spectral properties, have become essential tools for studying different functional areas of brain tissue. THz metamaterials are employed to detect brain tissue sections, with a focus on analyzing key functional areas such as the amygdala, motor cortex, auditory cortex, hippocampus, hypothalamus, and thalamus. By measuring the resonant frequencies and amplitude changes in each area, the ability of THz metamaterials to identify different brain regions is verified. The resonant frequencies and amplitudes in each brain functional area have undergone significant changes. Among them, the hippocampus shows the largest change in resonance peak amplitude(ΔA), increasing from 7.62% to 20.35%. The motor cortex, auditory cortex, and amygdala show significant resonance frequency shifts, with a shift amount(Δf) reaching (369±4.4) GHz, while the hypothalamus shows a shift of 23.77 GHz. These differences are closely related to the biophysical properties of each brain area. The study indicates that THz metamaterials can effectively distinguish the spectral characteristics of brain functional areas.
Precise diagnosis and personalized treatment of neurological diseases are crucial for improving patient outcomes. Terahertz(THz) metamaterials, due to their unique spectral properties, have become essential tools for studying different functional areas of brain tissue. THz metamaterials are employed to detect brain tissue sections, with a focus on analyzing key functional areas such as the amygdala, motor cortex, auditory cortex, hippocampus, hypothalamus, and thalamus. By measuring the resonant frequencies and amplitude changes in each area, the ability of THz metamaterials to identify different brain regions is verified. The resonant frequencies and amplitudes in each brain functional area have undergone significant changes. Among them, the hippocampus shows the largest change in resonance peak amplitude(ΔA), increasing from 7.62% to 20.35%. The motor cortex, auditory cortex, and amygdala show significant resonance frequency shifts, with a shift amount(Δf) reaching (369±4.4) GHz, while the hypothalamus shows a shift of 23.77 GHz. These differences are closely related to the biophysical properties of each brain area. The study indicates that THz metamaterials can effectively distinguish the spectral characteristics of brain functional areas.
