An extended interaction oscillator （EIO） generating 120 GHz wave in sub-terahertz waves is studied by using the three-dimensional electromagnetic simulation software CST and PIC codes. A rectangular reentrant couple...An extended interaction oscillator （EIO） generating 120 GHz wave in sub-terahertz waves is studied by using the three-dimensional electromagnetic simulation software CST and PIC codes. A rectangular reentrant coupled-cavity is proposed as the slow-wave structure of EIO. By CST, the circuit parameters including frequency-phase dispersion, interaction impedance and characteristic impedance are simulated and calculated. The operation mode of EIO is chosen very close to the point where βL = 2π with corresponding frequency 120 GHz, the beam voltage 12 kV and the dimensions of the cavity with the period 0.5mm, the height 3mm and the width 1.4mm. Simulation results of beam-wave interaction by PIC show that the exciting frequency is 120.85 GHz and output peak power 465 W with 12-period coupled-cavity with the perveance 0.17 μP. Simulation results indicate that the EIO has very wide range of the operation voltage.展开更多
利用CST studio suite程序对边耦合直线加速结构的加速腔及耦合腔进行建模仿真,并进行优化。加速腔结构由11个参数决定,优化过程需平衡多个参数,包括本征模式、高频特性、最大表面电场、有效分路阻抗及渡越时间因子;耦合腔的优化基于维...利用CST studio suite程序对边耦合直线加速结构的加速腔及耦合腔进行建模仿真,并进行优化。加速腔结构由11个参数决定,优化过程需平衡多个参数,包括本征模式、高频特性、最大表面电场、有效分路阻抗及渡越时间因子;耦合腔的优化基于维持本征模式3 GHz。结果表明,在26~120 MeV整个加速过程中,加速腔的有效分路阻抗为22.5~59.8 MΩ·m^(-1),加速梯度为11~14.7 MV·m^(-1)。展开更多
垂直外腔面发射激光器(VECSEL)可以实现大功率的高光束质量输出。针对外腔制作工艺复杂、腔体结构松散的缺点,研制了一种介质膜集成衬底表面外腔底面发射激光器。将衬底表面生长的多层介质绝缘薄膜与N-DBR、P-DBR共同构成复合腔结构,衬...垂直外腔面发射激光器(VECSEL)可以实现大功率的高光束质量输出。针对外腔制作工艺复杂、腔体结构松散的缺点,研制了一种介质膜集成衬底表面外腔底面发射激光器。将衬底表面生长的多层介质绝缘薄膜与N-DBR、P-DBR共同构成复合腔结构,衬底充当外腔。该结构能够抑制高阶模式,进而优化输出光谱及远场发散角等光束特性。在已有的理论指导下,制作了有源区直径为200μm、外腔腔长250μm的VECSEL。室温下,向器件连续直流注入3.4 A,测试得到输出功率为260 m W,远场发散角的半角宽度为3.8°,光谱半高全宽为0.046 nm。与常规结构底面发射VCSEL进行比较,发现VECSEL器件的光束质量得到了明显改善,实验结果与理论仿真结果有较好的一致性。展开更多
We report a 1.65μm square-Fabry–Pérot[FP]coupled cavity semiconductor laser for methane gas detection.The laser output optical power can reach 7.4 m W with the side mode suppression ratio about 40 d B.The wavel...We report a 1.65μm square-Fabry–Pérot[FP]coupled cavity semiconductor laser for methane gas detection.The laser output optical power can reach 7.4 m W with the side mode suppression ratio about 40 d B.The wavelength tuning range is 2 nm by adjusting the FP cavity injection current,covering the methane absorption line at 1653.72 nm.The lasing wavelength can also be tuned by adjusting the square microcavity injection current or temperature,respectively.Methane gas detection is successfully demonstrated utilizing this laser.展开更多
Transmission spectra of coupled cavity structures （CCSs） in two-dimensional （2D） photonic crystals （PCs） are investigated using a coupled mode theory, and an optical filter based on CCS is proposed. The performa...Transmission spectra of coupled cavity structures （CCSs） in two-dimensional （2D） photonic crystals （PCs） are investigated using a coupled mode theory, and an optical filter based on CCS is proposed. The performance of the filter is investigated using finite-difference time-domain （FDTD） method, and the results show that within a very short coupling distance of about 3λ, where ）, is the wavelength of signal in vacuum, the incident signals with different frequencies are separated into different channels with a contrast ratio of 20 dB. The advantages of this kind of filter are small size and easily tunable operation frequencies.展开更多
基金supported by the National Natural Science Foundation of China (Grant No 10676110)the National Basic Research Program of China (Grant No 2007CB310401)
文摘An extended interaction oscillator （EIO） generating 120 GHz wave in sub-terahertz waves is studied by using the three-dimensional electromagnetic simulation software CST and PIC codes. A rectangular reentrant coupled-cavity is proposed as the slow-wave structure of EIO. By CST, the circuit parameters including frequency-phase dispersion, interaction impedance and characteristic impedance are simulated and calculated. The operation mode of EIO is chosen very close to the point where βL = 2π with corresponding frequency 120 GHz, the beam voltage 12 kV and the dimensions of the cavity with the period 0.5mm, the height 3mm and the width 1.4mm. Simulation results of beam-wave interaction by PIC show that the exciting frequency is 120.85 GHz and output peak power 465 W with 12-period coupled-cavity with the perveance 0.17 μP. Simulation results indicate that the EIO has very wide range of the operation voltage.
文摘垂直外腔面发射激光器(VECSEL)可以实现大功率的高光束质量输出。针对外腔制作工艺复杂、腔体结构松散的缺点,研制了一种介质膜集成衬底表面外腔底面发射激光器。将衬底表面生长的多层介质绝缘薄膜与N-DBR、P-DBR共同构成复合腔结构,衬底充当外腔。该结构能够抑制高阶模式,进而优化输出光谱及远场发散角等光束特性。在已有的理论指导下,制作了有源区直径为200μm、外腔腔长250μm的VECSEL。室温下,向器件连续直流注入3.4 A,测试得到输出功率为260 m W,远场发散角的半角宽度为3.8°,光谱半高全宽为0.046 nm。与常规结构底面发射VCSEL进行比较,发现VECSEL器件的光束质量得到了明显改善,实验结果与理论仿真结果有较好的一致性。
基金supported by the National Key R&D Program of China(No.2017YFB0405301)。
文摘We report a 1.65μm square-Fabry–Pérot[FP]coupled cavity semiconductor laser for methane gas detection.The laser output optical power can reach 7.4 m W with the side mode suppression ratio about 40 d B.The wavelength tuning range is 2 nm by adjusting the FP cavity injection current,covering the methane absorption line at 1653.72 nm.The lasing wavelength can also be tuned by adjusting the square microcavity injection current or temperature,respectively.Methane gas detection is successfully demonstrated utilizing this laser.
文摘Transmission spectra of coupled cavity structures （CCSs） in two-dimensional （2D） photonic crystals （PCs） are investigated using a coupled mode theory, and an optical filter based on CCS is proposed. The performance of the filter is investigated using finite-difference time-domain （FDTD） method, and the results show that within a very short coupling distance of about 3λ, where ）, is the wavelength of signal in vacuum, the incident signals with different frequencies are separated into different channels with a contrast ratio of 20 dB. The advantages of this kind of filter are small size and easily tunable operation frequencies.
