Ultra-violet excited laser emission in Na2

Laser emission at different wavelengths in the range of 903–914 nm and around 2.5 m has been observed upon excitation of Na₂ by uv radiation from an excimer laser at 351 nm and an excimer pumped dye laser in this wavelength range. The emission is attributed to a cascade emission followed by . In addition, coupled with the laser emission around 910 nm, broad-band fluorescence peaking around 855.5 nm is observed which, eventually, may be the first observation of the bound-free transition in Na₂.     

脉冲放电激励的钡蒸气激光的研究

设计和制作了新型结构的金属蒸气激光放电管.用钡为激光介质,通过纵向高频快脉冲放电激励,在国内首次实现波长为113μm和150μm的红外钡蒸气激光振荡,激光成分主要集中在150μm这条谱线上,激光输出功率和功率密度分别达12W和333mWcm3.测量并讨论了各工作参量和激光输出特性之间的关系     

He–SrCl2 vapor laser excited by Blumlein discharge circuit

An investigation of a He–SrCl₂ vapor laser excited by Blumlein discharge circuit is performed. Dependences of laser output power on the working parameters are obtained by experiment. The optimal operating parameters for lasing on several strontium atom and ion lines are found. The multi-line average output power of 1.32 W and the power specific of 12.46 mW/cm³ are achieved, of which more than 78.1% is concentrated at the 6.45 μm laser line.     

脉冲放电激励的钡蒸气激光的研究

设计和制作了新型结构的金属蒸气激光放电管.用钡为激光介质,通过纵向高频快脉冲放电激励,在国内首次实现波长为1.13μm和1.50μm的红外钡蒸气激光振荡,激光成分主要集中在1.50μm这条谱线上,激光输出功率和功率密度分别达1.2W和33.3mW/cm3.测量并讨论了各工作参量和激光输出特性之间的关系.     

Infrared dye laser excited by a diode laser

A waveguide dye laser with an inner diameter of 30 μm and a length of 1.0 nm has been excited with a pulsed GaAlAs diode laser. The infrared-absorbing dye 5,5′-dichloro-11-diphenylamino-3,3′-diethyl-10,12-ethylenethiatri- carbocyanine perchlorate was used in tetramethylene sulfoxide solution. By changing dye concentration, laser wavelengths from 950 to 1005 nm were obtained.     

Fluorescence quenching in laser dyes by absorption from an excited singlet state

The effects of absorption of pump radiation from the first excited singlet state on the fluorescence quantum yield are calculated by numerical solution of simple rate equations, and compared with experiments performed earlier for the dye 7-diethylamino-4-methyl-coumarin at N₂-laser pumping. Analytical solutions for high and low pump intensities are found for the case of an optically thin solution.     

Fluorescence emission of excited hydrogen atoms after core excitation of water vapor

The Balmer emission from atomic hydrogen has been recorded across the resonances at the oxygen K edge of the water molecule using synchrotron radiation excitation. The emission is observed to be strongest at excitations to Rydberg resonances. The observations are interpreted using a qualitative model for the dynamics of the core-to-Rydberg excited molecule. The model links the quantum state of the core-excited water molecule via resonant Auger decay and subsequent dissociation to the state of the fluorescing hydrogen atom.     

Laser excited fluorescence of Na2

Fluorescence was excited in theB ¹Γ _u −X ¹Σ _g ⁺ system of Na₂, using the 488 and 514.5 nm radiations from a cw Ar⁺ laser. The fluorescence was monitored through a double monochromator employing photoelectronic detection. In the spectrum resulting from the 488 nm excitation, apart from a large number of fluorescence series, a previously unreported series could be identified. On either side of all the members of the strongest series a large number of collisional satellites were observed and assigned.     

Atomic and molecular fluorescence with long radiative decay times from laser excited Na2

Na₂ is excited (B¹Π_u←X¹Σ _g ⁺ ) in the presence of noble gases (20–700 Torr). The Na₂ fluorescence decay shows two lifetimes: a short component which corresponds to the well known lifetime of Na₂ in the B¹Π_u state [1], and a long component with a lifetime of about 0,1 μs which depends strongly on the noble gas density [2]. The same long lived radiative decay is also seen via the Na resonance fluorescence Na(3²S)←Na(3²P).     

Fluorescence image excited by a scanning UV-LED light

An optical scanning system using UV-LED light to induced fluorescence technology can enhance a fluorescence image significantly in a short period. It has several advantages such as lower power consumption, no scattering effect in skins, and multilayer images can be obtained to analyze skin disease. From the experiment results, the light intensity increases with increase spot size and decrease scanning speed, but the image resolution is oppositely. Moreover, the system could be widely used in clinical diagnosis and photodynamic therapy for skin disease because even the irradiated time of fluorescence substance is short but it will provide accurately positioning of fluorescence object.     

Compact waveguide CO2 laser excited by a RF power supply

The design and performance of radio frequency (RF) excited partial Z-fold waveguide CO2 laser with two channels are exposed. The length of the partial Z-fold channel is 3×460 mm and that of the single channel is 460 mm. The electrodes for the two channels are common and excited by a same RF source. According to our analysis, this kind of structure can greatly improve the laser offset frequency stability. In the experiments, we studied the variation of laser output power with gas pressure for two different channels.The maximum laser output power is about 23 W for the partial Z-fold channel and about 6 W for the single channel.     

Time resolved study of superelastic collisions in laser excited strontium vapor

We present a time-resolved experimental study of ionization by superelastic collisions in excited strontium vapor. Using short duration laser pulses for resonant excitation, we clearly observe that a delay time is necessary to reach runaway collisional ionization after the end of laser excitation.     

Electron spectrometry study of associative and penning ionization in laser excited sodium vapor

The first observation, by electron spectrometry, is reported in laser-excited sodium vapor of the primary low energy electrons produced by associative ionization and by Penning ionization of sodium atoms in highly excited n1 states. The sequential heating of these primary electrons has been observed in 1, 2 or 3 superelastic collisions with Na(3p) atoms. The variation of associative ionization was measured as a function of the excited state density by using inner-shell photoionization produced by synchrotron radiation. Finally, an associative ionization cross section of 3.8 X 10^-17 cm² and a Penning ionization cross section for the 5s state of 1.1 X 10^-12 cm² were found (within 50% uncertainty) for an oven temperature of 520 K.     

FIR NH3 cascade laser excited by a Q-switch laser

Short FIR laser pulses of high repetition rate are obtained by pumping NH₃ with the pulses of a passively Q-switched IR laser. The two cascade laser transitions observed show coupled relaxation oscillations. The pulse shapes and delay times are qualitatively in agreement with a four-level rate-equation model.Partially supported by Deutsche ForschungsgemeinschaftOn leave from Korea Standards Research Institute, Dae Deog Dan Ji, P.O. Box 3, Choong Nam, Korea, supported by Korea Science and Engineering Foundation     

Identification of excited states in Na2 by two-step polarization labeling

In two-step polarization labeling, as in polarization labeling, a polarized pump laser is tuned to a molecular transition. This produces an optical anisotropy in the upper and lower levels of the pump transition. A linearly polarized probe laser will experience a change in polarization when it interacts with these oriented levels of the molecule. Probe delays of several nanoseconds distinguish lower level depolarization from upper level depolarization. The technique has been applied to Na₂ to identify three new excited states. Preliminary values of some of the molecular constants are presented.