Numerical Study of Compact Terahertz Gas Laser Based on Photonic Crystal Fiber Cavity

Abstract

Abstract-We report a compact terahertz (THz) gas laser based on the cavity photonic crystal fiber (PCF). This compact structure consists of a large air core PCF constructed by high-density polyethylene (HDPE) tubes. The 2.52 THz wave can be generated in the reaction cell filled with the CH 3 OH gas. The reaction cell should shrink the volume of THz sources. The saturation intensity is analyzed based on the rate equations theory. Numerical calculations show that the THz wave can realize the fundamental mode transmission and obtain a lower confinement loss of 5.6 dB/m and the flat bending loss spectrum. The optimum pressure, pump threshold are analyzed and the THz output power can reach the magnitude of 10mW. We combined the THz pump technology and the excellent transmission characteristics of the PCF together. This compact THz gas laser gives a new method to realize the THz source with high beam quality, low transmission loss, well-distributed bending shape and small size.

Structure Design, Surface Modification, and Application of CNT Microwave‐Absorbing Composites

“…[ 85 ] summarized the effects of microstructures of organic‐derived carbon‐coated magnetic metal composites on absorbing performance. For the CNT‐based microwave‐absorbing composites, however, the review reports mainly focus on making a categorical summary of different categories of materials [ 54,94,115–120 ] and various preparation methods [ 121–123 ] so far. It is rare to summarize and evaluate CNT‐based absorbing materials from the perspective of macro and micro structures designation.…”

Tunable Temperature Characteristic of Terahertz Bragg Fiber Filled with Liquid Water

“…Various THz waveguides have been recently reported, including polymer fibers [11][12][13][14][15][16][17], metal tube waveguides [18], metal wire waveguides [19], and so on. The polymer fibers can achieve low loss and good flexibility.…”

“…The polymer fibers can achieve low loss and good flexibility. The types of THz fibers include solid-core fibers [16], hollow-core fibers [11][12][13][14][15], and porous-core fibers [17]. Among them, the hollow-core fibers have attracted a lot of research interest due to the low loss and easy inner modification with functional materials.…”

“…An argon gas-filled hollow-core fiber was designed as a pulse shaper to generate broadband and tunable time-domain spectroscopy in the THz by adjusting the argon gas pressure [11]. A fiber filled with methanol (CH 3 OH) gas in the gas laser was used as the reaction cell to shrink the volume of THz sources [12]. A THz fiber selectively filled with Potassium Chloride (KCL) was reported as Epsilon-Near-Zero (ENZ) material to ensure near-zero flattened dispersion [13].…”

Methanol-Filled Hybrid Photonic Crystal Fiber with High Birefringent and Negative Dispersion

“…Dual-core PCF is used as the sensing element of the hydrostatic pressure sensor [12]. The numerical method used in this study is FEM which is adequate for the analysis of general dielectric waveguide geometries [13,14]. The fiber exhibits a very large negative dispersion because of rapid slope change of the refractive indices at the coupling wavelength between the inner core and outer core.…”