He—Ne激光器粒子数反转径向分布光谱测量

用二维光学多道分析仪考察了He-Ne激光器在632.8nm激光振动和不振荡时氖能级3s_2和2p_k(k=1,2,……8,10)的侧光辐射,进行了Abel反演后,得到了3s_2和2p_k各能级粒子数和3s_2和2p_k间粒子数反转的径向分布,研究了此分布勺放电电流、632.8nm激光辐射强度间的关系,推算了在放电管中心3s_2和2p_k能级间受激辐射的激光增益。     

He—Ne激光器偏振特性的实验观察

一、内腔式He—Ne激光器的偏振特性由激光物理知,受激辐射场与入射辐射场具有相同的频率、位相、波矢(传播方向)和偏振,受激辐射场与入射辐射场属于同一模式。所以,腔内形成振荡的各个纵模,就其本身来说都是线偏振的。入射辐射场通常来自增益介质中的自发辐射,而自发辐射具有随机性,它存在各种各样的初始状态,因而各个纵模的位相和偏振方向不尽相同。一般规律是相邻纵模的偏振方向趋向正交偏振或者平行偏振。这除了与模间耦合竞争有关外,还与腔的各向同性或各向异性(谐振腔两反射镜上的多层介质膜,若沉积厚度均匀则称各向同性腔;反之称各向异性腔)、激发密度、外界条件等因素有关。激光管在工作过程中,由于热效应和震动造成腔长改     

提高稳频He—Ne激光器输出功率的研究

稳频Ｈｅ－Ｎｅ激光器的输出功率与谐振腔的损耗密切相关。本文对其中的布儒特角窗口带来的附加损耗进行了定量分析，指出布儒斯特窗片封接引起的各向异笥损耗是主要的腔内损耗来源。在实践上采用具有独特优点的锢封接技术，大大提高了布儒斯特窗片的封接质量，从而减小了腔的损耗，提高了稳频Ｈｅ－Ｎｅ激光器的输出功率。     

频率分裂与模竞争现象教学实验He—Ne激光器

一、引言激光课程中,激光的频率特性和激光烧孔效应及模竞争这两部分内容都是必需但又较难理解的内容,因而辅助教学的实验就显得尤为重要。通常进行激光频率特性实验的装置是扫描干涉仪。实验方法是让激光束射入扫描干涉仪,在示波屏上观察激光纵模。学生所能做的仅是学习如何使用扫描干涉仪和激光束含有几个纵模的感性认识。学生无法控制这些纵模(频率)以及纵模间隔。实验的质和量相对于纵模(频率)这一概念的重要性来说,显得不够充实。     

Uniphase1007型He—Ne激光管的纵向塞曼稳频研究

本文介绍采用拍频曲线晶振基准法首次在Uniphase 1007型长寿命商品He-Ne激光管上实现了无压电陶瓷调谐元件的塞曼双频稳频,采用可调永磁供磁,达到光频长期漂移5×10~(-9);双频双线偏振分离度1/60;双线偏振正交度89.5°;入锁及锁定情况良好.给出了塞曼双频激光器的调试技术.描述了输出光束偏振状态和纵模数关系的一个物理现象.     

连续可调谐1.52μmHe-Ne横向塞曼稳频激光器

研制成横向磁场中全内腔单模1.52μmHe—Ne激光器.提出了一种在锁定情况下,激光频率沿最佳S曲线连续调谐的方法.采用这种方法,激光频率在较宽范围内调谐,均达到较高频率稳定性.适于作单模光纤通讯的相干光源.     

提高稳频He－Ne激光器输出功率的研究

稳频Ｈｅ－Ｎｅ激光器的输出功率与谐振腔的损耗密切相关。本文对其中的布儒斯特角窗口带来的附加损耗进行了定量的分析，指出布儒斯特窗片封接引起的各向异性损耗是主要的腔内损耗来源。在实践上采用具有独特优点的锢封接技术，大大提高了布儒斯特窗片的封接质量，从而减小了腔的损耗，提高了稳频Ｈｅ－Ｎｅ激光器的输出功率。比如，腔长为１１０ｍｍ的６３３ｎｍ稳频Ｈｅ－Ｎｅ激光器的输出功率达到２．５～３．０ｍＷ。     

An intermittent frequency offset lock of a transverse Zeeman laser to an iodine stabilized He-Ne laser

A single-mode frequency stabilized laser with modulation-free and moderate power is desired as a light source for an ultra-high resolution interferometer system and/or a rapid laser calibration system. For this purpose, we developed a new stabilized laser system that utilizes intermittent control of a 2 mW transverse Zeeman stabilized He-Ne laser (Zeeman laser) with an iodine stabilized He-Ne laser (I2 stabilized laser). Because of the intermittent control, working time of the I2 stabilized laser is reduced. The Zeeman laser has two operational modes: independent and slave mode. In the independent mode, the Zeeman laser is stabilized through control of Zeeman beat frequency. Temperature dependent drift of the oscillation frequency during the independent mode is periodically corrected by the slave operation utilizing frequency offset locking to the I2 stabilized laser. Frequency instability of the Zeeman laser in independent and slave modes is 7.7X10-11 and 2.0X10-11, respectively, at the sampling time of 100 s.     

Intermittent frequency offset lock of a symmetric three-mode stabilized He-Ne laser to an iodine stabilized He-Ne laser

There is a need for an intense, unmodulated single-frequency stabilized laser light that guarantees absolute optical frequency in a rapid laser calibration or an ultra-high resolution interferometer. To obtain such a light, we developed a new laser system that uses an intermittent frequency offset lock of a symmetric three-mode stabilized He-Ne laser to an iodine stabilized He-Ne laser. The proposed laser system provides two operational modes: (1) independent and (2) slave mode. In the independent mode, frequency of the three-mode laser is stabilized via control of frequency difference between two intermode beats. The resultant output is a single longitudinal mode light of maximum intensity that locates at the top of the gain curve. Frequency instability of 8X10^-12 (at a sampling time of 100 s) which is better than conventional stabilized lasers is attained in the independent mode. Slow optical frequency drift during the independent mode is periodically corrected by the offset lock to the iodine stabilized laser (slave mode), resulting in accurate reset of the frequency drift. After reset of the frequency deviation, the three-mode laser is again operated in the independent mode. Due to such intermittent offset lock, duty factor of the iodine stabilized laser was reduced to a few % of continuous operation.     

基于飞秒光频梳的双频He-Ne激光器频率测量

利用光纤飞秒光频梳和外腔可调谐半导体激光器, 建立了一套双频He-Ne激光器频率测量系统. 选用铷钟作为系统的频率基准, 通过将外腔半导体激光锁定至光频梳使得其频率溯源至铷钟, 再利用外腔可调谐半导体激光与双频He-Ne激光器输出的正交偏振激光拍频, 同时测量两路正交偏振激光频率. 将可调谐半导体激光器锁定至光频梳第1894449个梳齿, 其绝对频率为473612190000.0±2.7 kHz, 相对不确定度为5.7×10^-12. 对商品双频He-Ne激光器进行频率测量实验, 双频He-Ne激光器水平方向偏振激光频率均值为473612229934 kHz, 竖直方向偏振激光频率均值为473612232111 kHz, 平均时间为1024 s的相对Allan标准差为5.2×10^-11, 频差均值为2.177 MHz, 标准偏差为2 kHz.     

双纵模He-Ne激光器稳频稳幅的时间相干时谱法(理论部分)

本文提出了一种实现双纵模He-Ne激光器稳频稳幅的新方法——时间相干时谱法.并分析了其调谐特性,介绍了相应的实验装置.     

光场横向效应导致CO2激光器混沌运转的实验研究

对横向效应导致单纵模多横模CO_2激光器失稳进行了实验研究.观测到了经各种途径到达的激光混沌态,并对其物理机制进行了探讨.     

A technique for frequency stabilization of an internal mirror He-Ne laser

A technique for frequency stabilization of an internal mirror He-Ne laser using phase sensitive detection without cavity length modulation is suggested. The orthogonally plane polarized modes are separated and then convered into two photoelectric signals using two photodetectors. The photoelectric signals are switched alternately so as to generate a square wave, whose amplitude is proportional to the intensity difference between the two orthogonal polarizations. A lock-in amplifier is used to detect this square wave, with the switching frequency as reference. The phase detected signal is used for thermal stabilization of the laser. The frequency stability of 5 × 10⁻⁹ was obtained with an integration time of 1 s.     

Accurate Stabilization of a 3 mW Single-Mode Output He-Ne Laser by Intermittent Frequency Offset Locking to an Iodine Stabilized He-Ne Laser

A high-power, unmodulated frequency standard laser light with low running cost is a powerful tool for industrial measurement involving laser calibration and interferometry in length and shape. To obtain such a laser light, we developed an intermittent frequency offset locked laser (IFOL laser). This laser system, composed of an iodine stabilized He-Ne laser (I₂SL) and a high-powered symmetric three-mode He-Ne laser (HP-3ML, optical output=5 mW), provides two stabilization operational modes: (1) independent mode (I-mode) and (2) slave mode (S-mode). Utilizing the frequency pulling effect, HP-3ML is stabilized at the condition of symmetric three-mode oscillation, and a 3 mW single-mode light with frequency instability of 10^-12 is obtained (I-mode). When the optical frequency deviates from the allowed limit during I-mode, HP-3ML is temporarily offset-locked to I₂SL (S-mode) with frequency resettability of 10^-10 and frequency instability of 10^-12. After completion of the drift reset in S-mode, HP-3ML is stabilized in I-mode again, and then I₂SL is turned off. In a typical case of allowed drift in ±1 MHz, repetitive operation of I-mode for 10 days and S-mode for 5 min was satisfactory. Such an intermittent operation reduces the working time of I₂SL dramatically, resulting in low running cost that enables long-term use in industrial measurement.     

The optimal design for weak optical feedback semiconductor laser with frequency modulation

In this paper the frequency modulation characteristics the semiconductor laserwith weak optical feedback are presented,considering both the frequency deviation and thespurious intensity modulation.The frequency modulation can be realized without spurious in-tensity modulation under proper feedback conditions.There is an optimal feedback intensity tomaximize the frequency deviation.     

利用稳频激光稳定F-P腔腔长的研究

为实现对F-P腔腔长的控制,设计了F-P腔腔长锁定控制系统。该系统以633nm稳频激光作为基准光源,通过控制系统驱动压电陶瓷调节F-P腔的腔长,以实现将F-P腔的谐振频率锁定到基准光源的频率上。实验结果表明,该方案切实可行,锁定后的F-P腔腔长的不确定度可达10-10量级。该方法在原子沉积技术中对于实现沉积台的稳定具有重要的指导意义。