Measurement of flow fluctuations in single longitudinal mode pulsed dye laser

A simple technique had been demonstrated for measuring flow-induced fluctuations in the single longitudinal mode (SLM) pulsed dye laser. Two prominent frequency components of 10.74 Hz and 48.83 Hz were present in the output of the Nd:YAG-pumped SLM dye laser. The flow-induced frequency component of 48.83 Hz was present due to the revolution per minute of the motor attached to the magnetically coupled gear pump. The time average bandwidth of 180 MHz has been obtained for this SLM dye laser. The effect of pump pulse energy on the bandwidth of the SLM dye laser was studied. The bandwidth of the SLM dye laser was increased to 285 MHz from 180 MHz, when the pump pulse energy was increased to 0.75 mJ from 0.15 mJ for a constant dye flow velocity of 0.5 m/s.     

Temporal dynamics of high repetition rate pulsed single longitudinal mode dye laser

Theoretical and experimental studies of temporal dynamics of grazing incidence grating (GIG) cavity, single-mode dye laser pumped by high repetition rate copper vapour laser (CVL) are presented. Spectral chirp of the dye laser as they evolve in the cavity due to transient phase dynamics of the amplifier gain medium is studied. Effect of grating efficiency, focal spot size, pump power and other cavity parameters on the temporal behaviour of narrow band dye laser such as build-up time, pulse shape and pulse width is studied using the four level dye laser rate equation and photon evolution equation. These results are compared with experimental observations of GIG single-mode dye laser cavity. The effect of pulse stretching of CVL pump pulse on the temporal dynamics of the dye laser is studied.     

A frequency locked, single mode pulsed dye laser. Application to single frequency tunable UV generation

This paper presents a new dye laser arrangement in which superposition of both cw and pulsed excitation permits to get a single mode pulsed tunable laser light beam. After amplification, this enables to generate single frequency tunable UV light with good conversion efficiency. An example is given of a high resolution study of Rb Rydberg states.     

A tunable,single mode,injection-locked flashlamp pumped dye laser

A tunable, very narrow bandwidth, flashpumped dye laser is described. Publse energies up to 50 mJ at a bandwidth of less than 30 MHz, and with a divergence of 0.4 mrad, are obtained. Spectral narrowing and tuning is achieved by injection locking of the pulsed laser to the radiation, of a tunable cw dye laser. The cavity is designed for single longitudinal and transverse mode operation, with a mode diameter large enough to fill the active medium. This work was supported in part by the Israel commission for Basic Research, and in part by a grant from the United States Israel Binational Science Foundation (BSF), Jerusalem, Israel.     

A stable and tunable linear polarization single longitudinal mode fiber ring laser

A stable and tunable linear polarization single longitudinal mode fiber ring laser is proposed and demonstrated. A high extinction ratio spatial mode interference filter utilizing two-mode graded-index fiber supresses irregular side modes effectively, the combination of fiber polarizer and polarization maintaining fiber act as a polarization dependent comb filter, and tunable bandpass filter is adopted to select proper lasing wavelength. The power fluctuation and wavelength fluctuation at 1549.88 nm are less than 0.05 dB and 0.02 nm in 1 h, respectively. Only one longitudinal mode appears within a free spectral range of 7.5 GHz, and the degree of polarization in percentage is approximately as high as 99.07%.     

腔内带圆形空心波导的可调谐窄带脉冲染料激光器

本文报道了一种腔内带圆形空心波导和掠入射光栅的可调谐窄带脉冲染料激光器;实验结果表明:该激光系统能获得基横模、窄频带和高效率的激光输出。文中对系统设计机理也进行了分析。     

A widely tunable dual-wavelength erbium-doped fiber ring laser operating in single longitudinal mode

A new mechanism to induce polarization hole burning effect in Er-doped fiber ring lasers is presented. By using this effect, incorporating with the counter-propagation of the two light beams, the inhomogeneous in the gain medium broadening was significantly increased, and thus a stable dual-frequency Er-doped fiber ring laser operating in single longitudinal mode and single-frequency was demonstrated. Frequency spacing was tunable from 0.47 GHz to THz.     

A single mode flashlamp-pumped dye laser

A flashlamp-pumped dye laser capable of single transverse and longitudinal mode operation is described. The maximum untuned power output is 2 MW cm^-2, TEM₀₀ mode. By employing three intracavity Fabry—Pérot etalons, a minimum spectral width of 4 MHz, stable to within 12 MHz, has been obtained.     

Single mode operation of a tunable cw dye laser

Using the differential absorption method the NO₂ concentration within the plume of a smoke stack and over the area of a chemical factory was measured.     

Two-wavelength single mode grazing incidence dye laser

Two-wavelength single mode operation of a N₂-laser pumped dye laser is described. The proper choice of a grazing incidence grating and highly selective cavity elements provided a stable operation of the laser. A single mode spectrum of 310 ± 50 MHz is measured and both wavelengths are independently tunable over the entire gain profile of the R6G DN dye.     

Photonic generation of tunable microwave signals by beating a dual-wavelength single longitudinal mode fiber ring laser

A novel method of generating tunable microwave signals in the photonic domain is proposed. Eighteen pairs of stable dual-wavelength single longitudinal mode lasings are achieved by incorporating a fiber Bragg grating based Fabry–Pérot filter and a tunable fiber grating into a fiber ring cavity. The frequency of the generated microwave signal obtained by beating the dual-wavelength laser with a photodetector can be tuned simply through configuring the working wavelength of the laser. A series of microwave frequencies of 9.4885, 9.572, 9.7111, 9.8498, 9.9598 and 10.0712 GHz are generated experimentally. The proposed method is useful in applications such as wireless access networks, sensor networks, radio-over-fiber systems and software-defined radio. PACS 41.20.-q; 42.55.Wd; 41.81.-i     

Spatially-hole-burned distributed feedback dye laser produced tunable single picosecond pulses

A new type of distributed feedback dye laser is described in which the Bragg grating is formed by spatial hole-burning. With a simple excimer laser pumped arrangement, single high stability 6 ps pulses were generated. The pulses were nearly transformlimited and were 33 times shorter than the rise time of the pulse which created the Bragg grating.on leave from JATE University, Department of Experimental Physics, Dóm tér 9, H-6720 Szeged, Hungary     

Single longitudinal mode interaction between a uranium atomic beam and a modified Hänsch-type pulsed dye laser

Laser-induced fluorescence is used as a diagnostic tool for testing the tuning between a longitudinal mode of a nitrogen-pumped dye laser and a uranium spectroscopic level in an atomic beam. According to a simple resonator model, the tuning instabilities can be ascribed to thermal drifts in the dye-laser system. Problems encountered in attempting a single mode scanning are also described.The work described in this paper was carried out at the ENEA Laboratory while P. Benetti was assigned to this Laboratory (1981)     

Thin-film narrowband tunable dye laser

We report a relatively simple system for obtaining a smoothly frequency tunable narrowband laser radiation. The action of the system is based on the possibility of quasiwaveguide generation of the amplifying layer inserted between two passive dielectric media. The retunable radiation in the wavelength range 570–610 nm was obtained and the generation line width was 0.01 nm.     

脉冲单纵模激光器中标准具精度与选模性能

根据脉冲单纵模激光器中的关键器件F-P标准具的选模原理,定量分析了不同参数F-P标准具的加工厚度精度、角度放置精度以及腔长变化对激光器纵模选择性能产生的影响,得到了对不同参数标准具的光学厚度偏差进行补偿所需的角度偏移量,研究了入射角度对标准具中心波长偏移的影响。这些结果对于脉冲单纵模激光器的机械结构设计、器件加工允差与装配调节精度的设计具有重要意义。在线型腔F-P标准具选模激光器中,得到了最大单脉冲能量8.41 J,脉冲宽度32 ns,近衍射极限的单纵模激光脉冲输出。     

脉冲单纵模激光器中标准具精度与选模性能

根据脉冲单纵模激光器中的关键器件F-P标准具的选模原理,定量分析了不同参数F-P标准具的加工厚度精度、角度放置精度以及腔长变化对激光器纵模选择性能产生的影响,得到了对不同参数标准具的光学厚度偏差进行补偿所需的角度偏移量,研究了入射角度对标准具中心波长偏移的影响。这些结果对于脉冲单纵模激光器的机械结构设计、器件加工允差与装配调节精度的设计具有重要意义。在线型腔F-P标准具选模激光器中,得到了最大单脉冲能量8.41 J,脉冲宽度32 ns,近衍射极限的单纵模激光脉冲输出。     

Two-wavelength self-seeded pulsed tunable laser

A compact self-seeded pulsed tunable laser is described. Its optical cavity comprises a diffraction grating, operating at a grazing angle of incidence as a spectral selector and narrow-band spectral gate. The grating couples two partially overlapping laser channels: a highly selective master laser and a nonselective slave laser. Due to the implemented efficient intracavity self-seeding the laser emits spectrally pure single-longitudinal-mode radiation at two independently tunable wavelengths, with an efficiency and output energy that are typical for nonselective lasers. Results of the experimental investigation of the laser’s output characteristics are presented. Received: 12 March 2001 / Revised version: 10 December 2001 / Published online: 7 February 2002     

Saturation of sodium fluorescence in a flame irradiated with a pulsed tunable dye laser

Theoretical and experimental saturation curves and associated saturation parameters for the Na-D doublet in an H₂-O₂-Ar flame at 1 atm (T=1700 K) are compared. These parameters are found to agree within the experimental error of 25%. An explanation based on the spatial and temporal distribution of the laser intensity is given for the deviating saturation curves reported by various authors. The shape of the fluorescence pulse is shown to depend on the O₂ concentration in the flame. A lower limit for the rate constant of the doublet mixing transition is estimated from the ratio of the saturated fluorescence intensities of the Na-D components and found to be 3x10⁸s^-1. Conclusions are drawn which restrict the use of saturated atomic fluorescence intensities as a measure for the total atomic number density in the flame.     

Temporal synchronization of independently tunable single longitudinal mode hybrid CO2 lasers

We report a quantitative study of temporal synchronization of two independently tunable, single longitudinal mode, hybrid CO₂ lasers, sharing a common high pressure section. The theoretical estimates for the dependence of the laser pulse build up time on the cw section pressure are in satisfactory agreement with the experimental results. Further, we show that temporal synchronization over a larger frequency range with no significant degradation of peak power or longitudinal mode selection is possible, by utilising the cw section gain length and cavity Q as additional control parameters.     

Simultaneous tunable two-wavelength ultraviolet dye laser

A dye laser system allowing simultaneous tunable two-wavelength oscillationin the ultraviolet has been developed. An intra-cavity dual beam system employs one diffraction and grating frequencydoubling at both wavelengths is achieved with bidirectional illumination of a single KDP crystal. The system characteristics will be discussed with respect to application in a differential absorption lidar operating around 300 nm for atmospheric SO₂ detection.