Tunable terahertz gas laser based on a germanium spectrum splitter

Liu, Chuang; Zheng, Li; Wang, Jiatian; Li, Mengnan; Li, Lijuan; Liu, Tao

doi:10.1007/s00340-020-07486-5

Cited by 3 publications

(4 citation statements)

References 24 publications

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“…The proposed approach to coherent amplitude modulation sensing is a variation of various radio engineering, solid-state methods. Low-frequency noise, kilohertz, megahertz ranges are used; there are names of wave modulation, frequency modulation, and nanoparticle spectroscopy [5][6][7][8].…”

Section: Resultsmentioning

confidence: 99%

Coherent Amplitude Modulation in a Laser Gas Sensor

Zhanabaev

2023

Eurasian phys. tech. j.

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The article is devoted to a current topic in science and technology -determining the type and concentration of gas using a laser. At close values of green laser radiation intensity and bias voltage, interference patterns of the time series of the photodiode output signal were obtained. The degree of coherence (more than ~0.1) made it possible to distinguish between the types of gases and their concentrations. Signal coherence was controlled by Allan deviation values.The novelty of the research method is the choice of the harmonic of the electrical network asthe main modulation frequency. It is shown that the correlation functions and the corresponding power spectra are sensitive to low-frequency fluctuations of molecules and their clumps. This allows the results and methods of this work to be used in specific cases instead of large-sized and expensive complexes of optical instruments at room pressure and temperature.

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Section: Resultsmentioning

confidence: 99%

Coherent Amplitude Modulation in a Laser Gas Sensor

Zhanabaev

2023

Eurasian phys. tech. j.

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“…Liu et al. 102 proposed a tunable optically pumped

gas laser with a germanium ealton serving as spectrum splitter, four THz laser lines corresponding to a conversion efficiency of

were observed in the range of 0.5 to 1.7 THz by tuning the incident angles and pump wavelengths.…”

Section: Modern Thz-wave Emittersmentioning

confidence: 99%

“…100 Wienold et al 101 presented a gas laser based on QCL pumped 15 NH 3 molecules; several laser lines with the output power of up to 30 μW were obtained around 4.5 THz by exploiting the molecular symmetry and employing an alternative resonator. Liu et al 102 proposed a tunable optically pumped CH 3 F gas laser with a germanium ealton serving as spectrum splitter, four THz laser lines corresponding to a conversion efficiency of ∼10 −3 were observed in the range of 0.5 to 1.7 THz by tuning the incident angles and pump wavelengths.…”

Section: Optically Pumped Gas Lasermentioning

confidence: 99%

Cellular effects of terahertz waves

et al. 2021

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. Significance: An increasing interest in the area of biological effects at exposure of tissues and cells to the terahertz (THz) radiation is driven by a rapid progress in THz biophotonics, observed during the past decades. Despite the attractiveness of THz technology for medical diagnosis and therapy, there is still quite limited knowledge about safe limits of THz exposure. Different modes of THz exposure of tissues and cells, including continuous-wave versus pulsed radiation, various powers, and number and duration of exposure cycles, ought to be systematically studied. Aim: We provide an overview of recent research results in the area of biological effects at exposure of tissues and cells to THz waves. Approach: We start with a brief overview of general features of the THz-wave–tissue interactions, as well as modern THz emitters, with an emphasis on those that are reliable for studying the biological effects of THz waves. Then, we consider three levels of biological system organization, at which the exposure effects are considered: (i) solutions of biological molecules; (ii) cultures of cells, individual cells, and cell structures; and (iii) entire organs or organisms; special attention is devoted to the cellular level. We distinguish thermal and nonthermal mechanisms of THz-wave–cell interactions and discuss a problem of adequate estimation of the THz biological effects’ specificity. The problem of experimental data reproducibility, caused by rareness of the THz experimental setups and an absence of unitary protocols, is also considered. Results: The summarized data demonstrate the current stage of the research activity and knowledge about the THz exposure on living objects. Conclusions: This review helps the biomedical optics community to summarize up-to-date knowledge in the area of cell exposure to THz radiation, and paves the ways for the development of THz safety standards and THz therapeutic applications.

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“…proposed two types of quad-beam splitters based on coding metamaterials, which can achieve 1×4 and 2×2 beams, within the terahertz frequency range. Liu et al 20 . designed a triple-channel reflective beam splitter at the terahertz of 2.52 THz with a connecting layer under a second Bragg incidence.…”

Section: Introductionmentioning

confidence: 99%

Polarization insensitivity induced for 1 × 9 splitter with T-type SiO2 grating ridge

Liang,

Wang,

Shi

et al. 2024

Opt. Eng.

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To reduce the polarization sensitivity, a T-type grating with the material SiO 2 is proposed on a reflective layer made of aluminum material. Based on structural parameters derived from rigorous coupled-wave analysis and simulated annealing, the described reflection beam splitter enables a nine-port separation under normal incidence. In addition, it demonstrates exceptional and uniform diffraction efficiency. For transverse electric polarization, the diffraction efficiencies of 0th, ±1st, ±2nd, ±3rd, and ±4th are 10.02%, 11.70%, 10.85%, 11.00%, and 10.03%, respectively. For transverse magnetic polarization, the diffraction efficiencies of 0th, ±1st, ±2nd, ±3rd, and ±4th are 12.54%, 10.13%, 9.51%, 10.46%, and 11.89%, respectively. The finite element technique is used to verify the diffraction efficiency values. In addition, a thorough analysis of the fabrication tolerance, wavelength bandwidth, and electromagnetic field dispersion is conducted. The outcome shows that the suggested grating structure has outstanding uniformity and efficiency, and these studies greatly enhance our knowledge of and progress toward the creation of the nine-port beam splitter. Consequently, there is a lot of room for the implementation of the suggested grating in multi-channel optical communication systems.

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Tunable terahertz gas laser based on a germanium spectrum splitter

Cited by 3 publications

References 24 publications

Coherent Amplitude Modulation in a Laser Gas Sensor

Coherent Amplitude Modulation in a Laser Gas Sensor

Cellular effects of terahertz waves

Polarization insensitivity induced for 1 × 9 splitter with T-type SiO2 grating ridge

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