西安理工大学陕西省超快光电与太赫兹科学重点实验室，陕西 西安 710048
基于太赫兹时域光谱（THz-TDS）系统，使用两个相互垂直的光电导天线构建了1×2 GaAs光电导太赫兹源阵列。通过调控各个阵元的偏置电压，对其辐射太赫兹波的偏振方向进行研究。结果表明：在已实现光电导发射天线阵列的高效合成以及可同时检测脉冲太赫兹波的振幅、相位及偏振态的探测天线的基础上，通过调控各个阵元的偏置电压分别改变了平行和垂直两个阵元辐射太赫兹波的强度；经过1×2 GaAs光电导太赫兹源阵列在远场的同步合成，可产生不同偏振方向的脉冲太赫兹波，实现了以全电控的方式产生任意偏振方向太赫兹波的光电导太赫兹辐射源。
太赫兹时域光谱系统 太赫兹辐射源 光电导天线阵列 偏振方向 激光与光电子学进展
2023, 60(18): 1811022
Author Affiliations
Abstract
State Key Laboratory of Photon-Technology in Western China Energy, International Collaborative Center on Photoelectric Technology and Nano Functional Materials, Institute of Photonics & Photon Technology, School of Physics, Northwest University, Xi’an 710069, China
We report a Yb-doped mode-locked fiber laser based on a nonlinear amplifying loop mirror (NALM), which is all-normal-dispersion (ANDi), and allows the output wavelength to be tunable. The laser can generate a stable femtosecond dissipative soliton with a maximum output power of 196 mW. Its repetition rate is 112.4 MHz, and the final pulse duration is 236 fs. By adjusting the angle of the reflective diffraction grating, the mode-locked fiber laser was realized to tune the output with a tuning range of 54 nm from 1011.8 nm to 1065.6 nm. To the best of our knowledge, this is the widest tuning range of an ANDi Yb-doped mode-locked fiber laser based on NALM.
all-normal-dispersion wavelength tuning mode-locked fiber laser Chinese Optics Letters
2023, 21(6): 061402
1 西安理工大学 电气工程学院, 陕西 西安 710048
2 西安理工大学 陕西省超快光电技术与太赫兹科学重点实验室, 陕西 西安 710048
3 西安理工大学 应用物理系, 陕西 西安 710048
里德堡(Rydberg)原子具有极大的极化率和电偶极矩, 并对外电场十分敏感, 因此可利用 Rydberg原子的量子干涉效应实现微波和太赫兹场的高精确度、自校准测量, 基于 Rydberg原子对太赫兹波频率上转换效应可实现太赫兹波段的实时成像。本文回顾了利用 Rydberg原子的电磁诱导透明效应和 Autler-Townes分裂现象实现对微波和太赫兹场的高精确度探测的研究进展, 以及 Rydberg原子在快速太赫兹成像方面的研究。
Rydberg原子 电磁诱导透明 太赫兹波 微波 太赫兹成像 Rydberg atom Electromagnetically Induced Ttransparency(EIT) THz wave microwave THz imaging 太赫兹科学与电子信息学报
2023, 21(2): 125
Qimeng Lin 1,2,3Li Yan 1,2,3Yuanqi Song 1,2,3Xuzhuo Jia 1,2,3[ ... ]Jintao Bai 1,2,3,**
Author Affiliations
Abstract
1 State Key Laboratory of Energy Photon-technology in Western China, Shaanxi Engineering Technology Research Center for Solid State Lasers and Application, Northwest University, Xi’an 710069, China
2 International Collaborative Center on Photoelectric Technology and Nano Functional Materials, Provincial Key Laboratory of Photo-electronic Technology, Northwest University, Xi’an 710069, China
3 Institute of Photonics & Photon-technology, Northwest University, Xi’an 710069, China
In this Letter, we demonstrated the switchable single- and dual-wavelength femtosecond soliton generation in single-mode Er-doped fiber lasers with the usage of carboxyl-functionalized graphene oxide (GO-COOH) saturable absorbers (SAs) for the first time, to the best of our knowledge. The fiber laser generated a stable single-wavelength conventional soliton at 1560.1 nm with a pulse duration of 548.1 fs. The dual-wavelength solitons centered at 1531.9 nm and 1555.2 nm with a spacing of approximately 23 nm can be obtained by adjusting the pump power of the cavity. Our experimental results indicated the GO-COOH has great potential to be used in ultrafast fiber lasers as broadband SAs.
fiber laser mode-locking dual-wavelength femtosecond soliton Chinese Optics Letters
2021, 19(11): 111405
西安理工大学陕西省超快光电技术与太赫兹科学重点实验室, 陕西 西安 710048
太赫兹单次测量技术可以对一些超快不可逆过程进行快速测量,在蛋白质变性、核爆模拟分析等领域具有广阔的应用前景。从飞秒激光放大器发出的光脉冲分成两束并分别经过两块光栅产生波前倾斜,一束作为抽运光激发铌酸锂晶体,基于光整流效应产生高功率太赫兹波;另一束作为探测光,采用正交平衡探测法探测。利用该光路产生太赫兹脉冲并对其进行单次测量,系统的时间窗口为16.8 ps,频谱范围覆盖0.1~1.6 THz。
太赫兹技术 测量 太赫兹波 波前倾斜 单次测量
Yang Bai 1,2,3,†Bing Bai 1,2,3Diao Li 1,2,3Yanxiao Sun 1,2,3[ ... ]Jintao Bai 1,2,3
Author Affiliations
Abstract
1 National Key Laboratory of Photoelectric Technology and Functional Materials (Culture Base), Institute of Photonics and Photon-Technology, Northwest University, Xi’an 710069, China
2 Shaanxi Engineering Technology Research Center for Solid State Lasers and Application, Xi’an 710069, China
3 Provincial Key Laboratory of Photo-electronic Technology, Institute of Photonics and Photon-Technology, Northwest University, Xi’an 710069, China
We report a cavity-dumped 1123 nm laser with narrow pulse width and high peak power by an MgO: LN crystal electro-optic (EO) modulator. Based on the structural optimization design of a folded biconcave cavity using the 808 nm pulsed laser diode (LD) side-pumped ceramic Nd: YAG rod, output pulses with maximum pulse energy and peak power up to 39.6 mJ and 9.73 MW were obtained, corresponding to 100 Hz repetition rate and 4.07 ns pulse width. The instabilities of pulse width and pulse energy were $\pm$1.55% and $\pm$2.06%, respectively. At the highest repetition rate of 1 kHz, the pulse energy, pulse width, and peak power were 11.3 mJ, 5.05 ns, and 2.24 MW, respectively. The instabilities of pulse width and pulse energy were $\pm$2.65% and $\pm$3.47%, respectively.
cavity-dumped high peak power MgO: LN EO 1123?nm laser short pulse width High Power Laser Science and Engineering
2018, 6(1): 010000e4
孙江 1,2,3,*侯磊 1,2,3林启蒙 1,2,3白杨 1,2,3[ ... ]白晋涛 1,2,3,4
1 西北大学 光子学与光子技术研究所光电技术与纳米功能材料国际联合研究中心, 西安 710069
2 西北大学 光子学与光子技术研究所陕西省全固态激光及应用工程技术研究中心, 西安 710069
3 西北大学 光子学与光子技术研究所陕西省光电子技术重点实验室, 西安 710069
4 西北大学 物理学院, 西安 710069
利用啁啾光纤布拉格光栅作为光谱滤波器和色散控制元件来控制掺镱保偏锁模光纤激光的光谱形状和腔内色散.实验装置采用线性腔设计, 利用半导体饱和吸收镜作为锁模器件, 实现掺镱保偏光纤激光器的被动锁模激光输出.当泵浦功率为52 mW时, 获得了脉冲宽度为4.26 ps, 重复频率为15.7 MHz, 平均功率为9.8 mW 的稳定锁模脉冲激光输出.输出激光中心波长为1 030 nm, 3dB谱宽为7.2 nm, 对应理想傅里叶变换极限脉宽约为150 fs.
锁模激光 掺镱光纤激光器 保偏光纤 可饱和吸收体 啁啾光纤光栅 Mode-locked laser Yb-doped fiber laser Polarization-maintaining Saturable absorber Chirped fiber Bragg gratings 李蒙蒙 1,2,3,4,*侯磊 1,2,3林启蒙 1,2,3郭鸿宇 1,2,3[ ... ]白晋涛 1,2,3,4
1 西北大学 光子学与光子技术研究所光电技术与纳米功能材料国际联合研究中心, 西安 710069)
2 西北大学 光子学与光子技术研究所陕西省全固态激光及应用工程技术研究中心, 西安 710069
3 西北大学 光子学与光子技术研究所陕西省光电子技术重点实验室, 西安 710069
4 西北大学 物理学院, 西安 710069
介绍了一种全正色散宽光谱被动锁模掺镱光纤激光器, 利用非线性偏振旋转技术实现全正色散掺镱光纤激光器的被动锁模.当泵浦功率输出为500 mW时, 激光脉冲输出功率大于139 mW, 重复频率约为28.1 MHz, 脉冲宽度为3.8 ps.为了进一步研究全正色散光纤激光器的宽光谱输出特性, 在腔内熔接50 m单模光纤, 同时去除双折射滤波片, 在泵浦功率为500 mW时, 观察到稳定锁模单脉冲耗散孤子, 光谱范围为1 005~1 140 nm, 输出激光脉冲最大平均功率为90 mW, 重复频率为3.58 MHz, 脉冲宽度为519 ps.
全正色散 掺镱光纤激光器 宽光谱 非线性偏振旋转 耗散孤子 All normal dispersion Ytterbium doped fiber laser Wide spectrum Nonlinear polarization rotation Dissipative soliton 
Baole Lu 1,2,3,*Limei Yuan 1,2,3Xinyuan Qi 4Lei Hou 1,2,3[ ... ]Jintao Bai 1,2,3,4
Author Affiliations
Abstract
1 National Key Laboratory of Photoelectric Technology and Functional Materials (Culture Base), Institute of Photonics and Photonics-Technology, Northwest University, Xi’an 710069, China
2 Shaanxi Engineering Technology Research Center for Solid State Lasers and Application, Xi’an 710069, China
3 Institute of Photonics and Photonics-Technology, Provincial Key Laboratory of Photoelectronic Technology, Northwest University, Xi’an 710069, China
4 School of Physics, Northwest University, Xi’an 710069, China
In this Letter, a single-frequency fiber laser using a molybdenum disulfide (MoS2) thin film as a saturable absorber is demonstrated. We use a short length of highly Yb-doped fiber as the gain medium and a fiber ferrule with MoS2 film adhered to it by index matching gel (IMG) that acts as the saturable absorber. The saturable absorber can be used to discriminate and select the single longitudinal modes. The maximum output power of the single-frequency fiber laser is 15.3 mW at a pump power of 130 mW and the slope efficiency is 15.3%. The optical signal-to-noise ratio and the laser linewidths are ～60 dB and 5.89 kHz, respectively.
140.3510 Lasers, fiber 140.3570 Lasers, single-mode 160.3380 Laser materials Chinese Optics Letters
2016, 14(7): 071404
1 徐州工程学院信电工程学院, 江苏 徐州 221008
2 电子科技大学计算机学院, 成都 611731
为了提高低照度视频的视觉效果, 常常利用高质量白天亮度来增强夜间 (低照度)视频。本文提出了一种亮度融合的视频增强方法。首先为了获取白天背景, 采用了平均 K帧的方法, 然后使用 Retinex理论, 提取了白天背景和夜间视频帧的亮度, 同时为了增强夜间移动物, 采用帧差法提取了夜间视频帧的移动物, 最后利用相同场景的白天背景亮度融合夜间帧的视频增强方法, 为了改善夜间移动物体的感知度, 提出了基于高斯滤波器的方法平滑移动物边界, 使得增强结果更自然。实验结果表明了该算法在提高视觉质量上的有效性, 且优于传统的方法。
视频增强 亮度融合 运动分割 高斯滤波器 video enhancement illumination fusion motion segmentation Gaussian filter
