Evidence of a competitive phenomenon between the 0.72 μm and 0.93 μm luminescences of Cu2O

Luminescence studies after excitation by a frequency doubled Nd : YAG laser showed evidence of competition between the 0.72 μm and 0.93 μm extrinsic luminescences in Cu₂O. The luminescence outputs of 0.72 μm and 0.93 μm were observed as a function of temperature at various laser intensities. The data suggest attenuation of 0.93 μm with the onset of 0.72 μm. This phenomenon has never been reported in the literature and represents a departure from the conventional theories on the luminescence of cuprous oxide.     

Accurate measurements for cyanic laser wavelengths using resonator interferometry

Accurate measurements are described for resonant wavelengths at 311 μm and 337 μm in the HCN laser using resonator interferometry. Analysis of the theoretical and experimental conditions for laser resonator interferometry indicates that the resonant wavelengths correspond to the medium in which the scanning mirror is displaced.     

Diode-side-pumped AO Q-switched Tm, Ho:LuLiF laser

Diode side pumped and acousto-optical (AO) Q-switched Tm, Ho, LuLiF laser at 2 μm wavelength obtained in a ring resonator is reported in this paper. The three LDAs were placed 120° apart around the laser rod of ?4 × 20 mm dimension. A ring resonator has been used for its At free run mode, four different output loss ouplers has been tried. When the output loss is 20%, 103 mJ per pulse at 1 Hz pulse repetition frequency has been obtained with the optical to optical energy conversion efficiency of 3.17%. At the Q-switched mode, the laser pulse energy is 30 mJ with the pulse width of 417 ns. The optical to optical energy conversion efficiency is 0.93%. The slope efficiency is 6.36 and 2.90% under the two running mode, respectively.     

Femtosecond Er<Superscript>3+</Superscript> fiber laser for application in an optical clock

The main elements needed for the realization of a compact femtosecond methane optical clock are developed and studied. A femtosecond laser system on an Er³⁺ fiber (λ = 1.55 μm) contains an oscillator, an amplifier, and a fiber with a relatively high nonlinearity in which the supercontinuum radiation is generated in the range 1–2 μm. In the supercontinuum spectrum, the fragments separated by an interval that is close to the methane-optical reference frequency (λ = 3.39 μm) exhibit an increase in intensity. The supercontinuum radiation is converted into the difference frequency in a nonlinear crystal to the range of the methane-reference frequency (λ = 3.3–3.5 μm), so that the frequency components of the transformed spectrum have sufficient intensities for the subsequent frequency-phase stabilization with respect to the methane reference. A system that stabilizes the pulse repetition rate of the femtosecond Er³⁺ laser is also employed. Thus, the repetition rate of the ultrashort pulses of the femtosecond fiber laser is locked to the methane reference. The pulse repetition rate is compared with the standard second. Thus, the scheme of an optical clock is realized.     

Generation of ultra-short pulses from high-gain narrow-linewidth lasers

Modified type mode-locking with many passive-mode excitation has been proposed to generate ultra-short light pulses from high-gain narrow-linewidth lasers, The mode-locking with single-active-mode (MLSAM) which is the useful and practical case of the modified type mode-locking has been analyzed taking into account the effect of large locking signal and the variation of the saturated gain along the light path. An experiment has been done by applying a 580 MHz large FM locking signal to a He-Ne 3.39 μm laser, a typical high-gain narrow-linewidth laser. As a result, 170 ps pulses have been obtained with several mW average power.     

高功率TEA CO2激光器两波长激光切换输出技术

 以TEA CO₂激光器通常采用的平-凹光学稳定腔为基础,提出了一种新的波长选支方法——输出窗口镀膜选支方法。利用一台高平均功率TEA CO₂激光器进行了选支实验研究,结合现有光学镀膜技术,得到了中心波长为9.3 μm的激光单谱线输出,其单脉冲能量及平均功率与激光器原中心波长10.6 μm单谱线输出的相应参数基本相当。研究发现,以相同单脉冲能量激光照射热敏纸时,中心波长9.3 μm激光光斑与中心波长10.6 μm的明显不同。同时,还设计出两波长窗口密闭免调切换装置,在一台激光器上实现了10.6,9.3 μm两个中心波长激光同等功率水平的免调切换输出,切换位置误差小于5″,密封性能满足使用要求。     

First experimental realization of a distributed feedback gas laser

Pulsed operation of an optically pumped CH₃F 496 μm distributed feedback (DFB) gas laser has been achieved by means of a hollow metallic waveguide resonator with deep periodic corrugations. Details of construction and first results are presented.     

Determining the resonator wavelength of VCSELs by Cauchy's integral formula

An algorithm is proposed for the computation of resonator wavelength of vertical cavity surface emitting lasers by Cauchy's formula and the method of lines. To calculate the laser modes an implicit eigenvalue problem has been solved. A pole-free complex function has been developed which allows the determination of all roots within the observed complex area. To test the proposed method several wavelengths of a 1.55 μm laser have been computed and compared with direct and iterative algorithms.     

Frequency of the methane-stabilized He-Ne laser at 3.39 μm measured relative to the 10.17 μm R(32) transition of the CO2 laser

The frequency difference between the methane-stabilized 3.39 μm He-Ne laser and the third harmonic of the 10.17 μm R(32) transition of the CO₂ laser was measured by harmonic generation and mixing in a tungsten-nickel diode. The difference is 55 200 952 ± 16 kHz. This result corroborates the findings of other workers and is special interest in current discussions to redefine the international metre.     

Directly diode-pumped high-energy Ho:YAG oscillator

We report on the high-energy laser operation of an Ho:YAG oscillator resonantly pumped by a GaSb-based laser diode stack at 1.9 μm. The output energy was extracted from a compact plano-concave acousto-optically Q-switched resonator optimized for low repetition rates. Operating at 100 Hz, pulse energies exceeding 30 mJ at a wavelength of 2.09 μm were obtained. The corresponding pulse duration at the highest pump power was 100 ns, leading to a maximum peak power above 300 kW. Different pulse repetition rates and output coupling transmissions of the Ho:YAG resonator were studied. In addition, intracavity laser-induced damage threshold measurements are discussed.     

Lamb-dip spectroscopy of some lower carbon-hydrogen compounds

The results of the investigations of some carbon-hydrogen compounds are represented, which were carried out on the basis of Lamb-dip spectroscopy utilizing a magnetically tunable He-Ne laser at the wavelength 3.39 μm.     

输出环状光束的新型激光谐振腔

提出一种输出环状光束的新型激光谐振腔,即在稳定激光谐振腔中采用外环耦合方式得到环状光束的输出。利用For-Li数值迭代算法求解此类激光谐振腔的积分方程,通过计算机编程计算了平面一凹球面稳定谐振腔的输出端平面镜在不同半径的情况下,谐振腔镜面上和衍射耦合输出场基模的振幅和相位分布。计算结果预示了当输出端平面镜半径小于通常的稳定腔的基模半径时,衍射耦合输出场有稳定的环状光束输出。实验中TEA CO2激光器采用印刷电路板预电离结构,增益长度90cm,腔长5m,球面全反射镜曲率半径20m,输出端平面镜半径4．5mm,得到了内环半径为4．5mm、外环半径为5．5mm的基模环形光斑输出。从而在理论上和实验上证实了该方案产生环状光束的可行性。     

电光调Q脉冲Ho:YLF激光器实验研究

2μm低重复频率高峰值功率高光束质量激光在中长波光参量非线性频率变换等领域具有较为广阔的应用前景。采用L型谐振腔结构,使用42 W的掺Tm光纤激光器泵浦Ho:YLF晶体。基于磷酸钛氧铷（RTP）电光调Q技术,实现了重复频率50 Hz、脉冲宽度18 ns、脉冲能量13.5 mJ、峰值功率0.75 MW的2.05μm Ho:YLF固体激光输出。光束的水平方向和竖直方向M2因子分别为1.4和1.1。该Ho:YLF固体激光器采用光纤激光器泵浦,具有结构紧凑的特点,为更高能量的Ho激光输出奠定了基础。     

Intracavity frequency doubling effects of passively mode－locked Nd：YAP pulsed laser in two different unstable resonators

Ｉｎｔｒａｃａｖｉｔｙｆｒｅｑｕｅｎｃｙｄｏｕｂｌｉｎｇｅｆｆｅｃｔｓｏｆｐａｓｓｉｖｅｌｙｍｏｄｅ－ｌｏｃｋｅｄＮｄ：ＹＡＰｐｕｌｓｅｄｌａｓｅｒｉｎｔｗｏｄｉｆｆｅｒｅｎｔｕｎｓｔａｂｌｅｒｅｓｏｎａｔｏｒｓＷＵＦｅｎｇｔｉｅ（Ｄｅｐａｒｔｍｅｎ...     

一种输出三波长超短光脉冲的激光源

利用对撞脉冲锁模非稳腔Ｎｄ：ＹＡＧ激光器，采用ＫＴＰ非线性晶体作腔外倍频，结合受激拉曼散射技术，在一台锁模激光器同时得到１．０６μｍ，０．５３μｍ，０．６３μｍ超短光脉冲的输出。     

分光路二维剪切干涉强激光腔镜变形检测系统

介绍一种分光路二维剪切干涉光电检测系统。该系统实现了两正交方向(二维)同时进行检测与计算机自动化数据处理;采用了一系列消噪声措施和两图像相减等技术,使得波前重构中能较好地采用简单的数值积分方法;并得到了在士10μm的测量范围内,方差不超过0. 257μm和0. 05μm的灵敏度。利用该系统成功地对强激光腔镜变形过程实现了动态检测。     

Thulium channel waveguide laser in a monoclinic double tungstate with 70% slope efficiency

Laser experiments were performed on buried, ridge-type channel waveguides in an 8 at.?% thulium-doped, yttrium-gadolinium-lutetium codoped monoclinic double tungstate. A maximum slope efficiency of 70% and output powers up to 300 mW about 2.0 μm were obtained in a mirrorless laser resonator, by pumping with a Ti:sapphire laser near 800 nm. To the best of our knowledge, this result represents the most efficient 2 μm channel waveguide laser to date. Lasing is obtained at various wavelengths between 1810 nm and 2037 nm.     

Hollow-cathode transverse discharge He−Ne and He−Cd+ lasers

An all-metal hollow-cathode laser tube consisting of a perforated cylindrical cathode surrounded by a coaxial cylindrical anode has been operated as a He?Ne laser at 0.6328, 1.15 and 3.39 μm, and as a He?Cd laser at red, green and blue visible wavelengths, using both de and pulsed-plus-dc excitation. Laser oscillation in He?Zn, Ne?Cd, Xe?Cd and Ar?Cd mixtures has also been obtained. The hollow-cathode discharge consists primarily of an intense cathode glow inside the cathode cylinder, giving a quiet, stable, low-voltage, positive-resistance discharge. Results for the He?Ne and He?Cd laser output versus partial and total pressures and discharge currents are presented. The unoptimized laser performance for the He?Ne case approaches but does not yet equal the conventional positive-column case, while the He?Cd performance for the charge-transfer-pumped green 5378Å line appears particularly promising.     

氙灯泵浦新型晶体Nd：S—VAP调Q激光器腔内倍频研究

采用氙灯泵浦晶体Ｎｄ：Ｓ－ＶＡＰ，ＫＴＰ晶体腔内倍频，实现了Ｎｄ：Ｓ－ＶＡＰ晶体０．５３２５μｍ绿光激光ＢＤＮ染料片调Ｑ运转，测量了输出绿光激光的特性及不同腔长和染料片小信号透过率情况下的输出能量及脉冲宽度，给出染料片调Ｑ腔内倍频的耦合波方程组，数值求解方程组，所得的理论数据与实验结果很好地相符。     

High power operation of a CW 28 μm water vapor laser

This paper describes the best operating conditions and power performance of a CW 28 μm water vapor laser, using a 3 m long discharge in a 3 cm diameter Pyrex glass tube. The laser cavity is a half symmetric conventional Fabry-Perot resonator, the plane mirror of which is a metal mesh used as an output coupler. The addition of a large amount of hydrogen to the water vapor leads to the production of high power laser emission. This laser delivers 230 mW of continuous output at 28 μm, corresponding to a volumetric power of 102 μW/cm³, the highest value ever reported.