In the widely-studied two-color laser scheme for terahertz (THz) radiation from a gas, frequency ratio of two lasers is usually fixed at $\omega_2/\omega_1=$1:2. We investigate THz generation with uncommon ratios. Our experiments show, first time, efficient new ratios $\omega_2/\omega_1=$1:4 and 2:3. observe that polarization can be adjusted by rotating longer-wavelength adjustment becomes inefficient other polarization; energy shows similar scaling laws different These observations are...

Metamaterial (MM) assisted terahertz (THz) label-free biosensing has promising applications. However, the sensitive THz detection of highly absorptive liquid samples remains challenging. Here, we present a novel multi-microfluidic-channel MM biosensor for sensing small-volume samples. The multichannels are set mostly in strong electric field enhancement area MM, which significantly decreases liquid's amount and enhances interaction between targets wave (thus increasing sensitivity). results...

The epidermal growth factor receptor (EGFR) plays an important role in the proliferation of various cancers, and expression level EGFR tumor tissues can provide a basis for diagnosis prognosis. Improving detection technology to achieve high sensitivity faster speed will benefit many types tumors. Trace biological samples be sensitively measured with terahertz (THz) metamaterial devices. Here, bow-tie array THz biosensor is presented modified gold nanoparticles (GNPs) antibodies specific...

We provide a chemical precipitation method to improve the thermoelectric properties of SnS. The largest <italic>ZT</italic> value is 0.41 at 848 K parallel pressing direction, which much higher than that mechanically-alloyed SnS materials.

We demonstrate an automatic recognition strategy for terahertz (THz) pulsed signals of breast invasive ductal carcinoma (IDC) based on a wavelet entropy feature extraction and machine learning classifier. The packet transform was implemented into the complexity analysis transmission THz signal from tissue sample. A novel index energy to Shannon ratio (ESER) proposed distinguish different tissues. Furthermore, principal component (PCA) method classifier were further adopted optimized...

Both solids and gases have been demonstrated as the materials for terahertz (THz) coherent detection. The gas-based detection methods require a high-energy probe laser beam bandwidth is limited in solid-based methods. Whether liquids can be used THz relax these problems has not yet reported, which becomes timely interesting topic due to recent observation of efficient wave generation liquids. Here, we propose scheme based on liquid water. When pulse fundamental are mixed free-flowing water...

In recent decades, terahertz (THz) radiation has been widely applied in many chemical and biomedical areas. Due to its ability resolve the absorption features of compounds noninvasively, it is a promising technique for recognition substances such as drugs or explosives. A key challenge THz technology be able accurately classify spectral measurements acquired unknown complicated environments, rather than those from ideal laboratory conditions. Support vector machine (SVM) deep neural networks...

We demonstrate a composite multiscale entropy (CMSE) method of terahertz (THz) signal complexity analysis to distinguish different biological tissues. The THz signals reflected from fresh porcine skin and muscle tissues were measured analyzed. statistically significant difference separation the two based on several parameters analyzed compared for spectroscopy imaging, which verified better performance CMSE further enhancement contrast among that interact with This process provides...

Cardiac Resynchronization Therapy (CRT) is an established pacing therapy for heart failure patients. The New York Heart Association (NYHA) classification often used as a measure of patient's response to CRT. Identifying NYHA class patients in electronic health record (EHR) consistently, over time, can provide better understanding the progression and assessment CRT effectiveness. However, rarely stored EHR structured data such information documented unstructured clinical notes. In this study,...

Water-based terahertz (THz) coherent detection scheme has been recently proposed, which overcomes the bandwidth limitation or high probe laser power demand in solid-/gas-based schemes. Here, we report a highly efficient THz method using ethanol with superior performances under mechanism of four-wave mixing. We systematically investigate energy ratios and relative polarizations between THz-induced second harmonic control (CSH) beams reveal that always exhibits significantly higher sensitivity...

We present a novel contrast-enhanced continuous-terahertz-wave imaging modality based on magnetic induction heating of superparamagnetic iron oxide nanoparticles (SPIOs), which yields highly sensitive increment in the reflection terahertz (THz) signal SPIO solution upon exposure to an alternating field. In differential and relative refection change focal-plane images before after field exposure, dramatic contrast is demonstrated between water with without SPIOs. This low-cost, simple, stable...

We report excitation-wavelength-dependent terahertz wave modulation via a preformed air plasma created by synchronized 800-nm laser pulse traveling orthogonal to the pump pulses. With plasma, both depth of energy and change in polarization increase with increasing excitation-laser wavelength. The results are well explained photocurrent model wavelength-dependent ionization rate. also experimentally detect refractive index two-color field changed plasma. These improve our understanding...

The terahertz Kerr effect (TKE) spectroscopy provides time-resolved measurement of low-frequency molecular motions liquids. Here, the intense broadband (THz) pulses resonantly excite multiple modes in pure ethanol and ethanol-water mixtures. For ethanol, obtained unipolar TKE response contains relaxation information extending over tens picoseconds, which originates from coupling between permanent dipole moment THz electric field. mixtures with different molar proportions, results observed on...

Rolandic epilepsy (RE) is the most common idiopathic focal childhood syndrome, characterized by sleep-activated epileptiform spikes and seizures cognitive deficits in school age children. Recent evidence suggests that this disease may be caused disruptions to thalamocortical circuit, resulting both an abundance of a paucity sleep spindles cortex during non-rapid eye movement (NREM); electrographic features linked symptoms, respectively. The neuronal mechanisms support competitive shared...

To make further understanding of terahertz (THz) wave generation from liquid water, we study THz emission water lines different diameters. The line with a smaller diameter generates stronger electric field for the diameters 0.2 mm to 0.5 mm. strength and polarity change relative position between incident laser line. Moreover, energy has an optimal radiation angle about 60°. A two-dimensional dipole array model is introduced illustrate phenomenon. Our observations contribute optimizing scheme source.

A novel explicit knowledge embedded space mapping (SM) optimization technique is presented in this paper. It generalizes the implementation procedure of efficient SM by introducing a buffer called between original coarse model and fine space, where ingredients can be completely different from those space. Therefore, generic scheme used to map arbitrary physical content through that built up with available radio frequency (RF) circuit CAD formula. The emphasis application proposed put on...

We examine the terahertz (THz) emission from air filament driven by two-color lasers with relatively longer wavelengths than 800 nm. The THz energy dependence on input laser increases more rapidly a wavelength, and scaling laws of as function fundamental wavelength vary for different optical powers, which is theoretically validated considering wavelength-dependent ionization rate. Furthermore, polarization undergoes continuous rotation since relative phase two pulses are adjusted through...

Controlling the polarization state of an optical pulse within a short gating time facilitates ultrafast all-optical data processing and recording. Using innovative modulation method such as transient terahertz Kerr effect (TKE), can be switched on sub-picosecond scale. In this work, we use high-frequency single-cycle (THz) pulses to excite effects materials explore potential shorten modulator. A low-density polyethylene (LDPE) material with good Kerr-related properties is proposed improve...