Timing and detuning studies of a synchronously pumped mode-locked dye laser

The timing relationship between a synchronously pumped mode-locked dye laser and its pump laser is explored experimentally and theoretically. The experimental data is in quantitative agreement with numerical solutions of a semiclassical model that includes no free parameters. The data also agrees qualitatively with an approximate, analytic distillation of this model which is presented here for the first time. Our study has a direct bearing on the jitter and the long term stability of these important ultrashort pulse lasers.     

Formation of synchronously mode-locked dye laser pulses

The generation process of synchronously mode-locked dye laser pulses within a linear cavity configuration containing a dye as an active medium and a bandwidth-limiting element is treated. The initial build-up of pulses from the noise as well as the steady-state regime are discussed. The circulation of the pulse in the cavity is described by a nonlinear integral equation. A computer analysis provides statements concerning the speed and the stages of the initial build-up. Furthermore it allows the discussion of steady-state regimes with good mode-locking as well as regimes outside of this region, for instance double and multiple pulse regimes or non-steady-state regimes.     

Rate equation simulation of a synchronously pumped dye laser

A simple rate equation model of a standing wave synchronously pumped dye laser yields output pulses which agree qualitatively and quantitatively with recent experimental observations. The shape, amplitude and temporal position of the simulated pulse varies dramatically, not only with cavity length detuning, but also with the gain to loss ratio. Features of pulse formation and stability are predicted which are precluded by the steady-state assumption present in most other models.     

Bistable operation of a dual-wavelength synchronously mode-locked cw dye laser

Bistable operation of a dual-wavelength synchronously mode-locked cw dye laser is reported. Wavelength switching is found to depend on the pump power and the dye laser cavity lengths.     

Theory of the synchronously pumped picosecond dye laser

The circulation of a synchronously mode locked dye laser pulse in a linear cavity configuration containing a dye cell as an active medium and a bandwidth-limiting element is treated. The condition that the pulse shape reproduces after each cavity round-trip provides a nonlinear integro-differential equation for the steady-state pulse shape. For the solution of this equation an approximate method, not limited to small pulse energies, is given and the pulse duration, intensity, energy, asymmetry of the pulse shape, stable regions and other interesting parameters are discussed.     

A mode-locked dye laser pumped by a xenon ion laser

Passive mode-locking of a rhodamine 6G dye laser has been achieved, using a pulsed xenon ion laser as a pumping source. A pulse width of 5 ps and a peak power of 4 kW have been obtained. Thermal problems were encountered, which adversely affected the operation of the dye laser. Work is in progress to improve these results.     

Study of synchronously mode-locked and internally frequency-doubledcw dye laser

The analysis of the characteristics of a synchronously mode-locked and internally frequency-doubled dye laser is presented. Dependence of dye laser pulse characteristics on the cavity length mismatch of the pump laser and dye laser is studied. Variation of the minimum pulsewidth with intracavity bandwidth and the harmonic conversion efficiency is presented in the form of graphs.     

Difference frequency generation with a synchronously mode-locked cw dye laser system

The generation of continuous trains of tunable infra-red pulses by the nonlinear mixing of the wave-lengths available from a self-contained synchronously mode-locked cw dye laser is described. The factors determining the optimization of the process are identified and their roles demonstrated.     

Near-infrared subpicosecond pulse generation in a synchronously mode-locked cw dye laser

Tunable subpicosecond pulses have been obtained from a synchronously mode-locked Oxazine-1 dye laser by tandem pumping with output pulses of a mode-locked Rhodamine 6G dye laser. The effects of cavity detuning on the pulse-width and the second harmonic power (the peak intensity of the autocorrelation trace) have been investigated. The experimental results are found to be in good agreement with those predicted by a recent model analysis.     

Picosecond and subpicosecon pulse generation in synchronously pumped mode-locked cw dye lasers

Generation of tunable near-infrared picosecond and subpicosecond pulses in a synchronously pumped cw mode-locked Oxazine-1-perchlorate dye laser has been investigated for different values of the important system parameters. The experimental results confirm the predictions of a simple theoretical model which describes the steady-state pulse duration in terms of gain modulation strength, pump power, intracavity bandwidth, pump pulse length and cavity detuning. For a pump-pulse length of 100 ps and a bandwidth of more than 500 Å for the intracavity tuning element dye-laser pulses as short as 0.35 ps have been obtained. Under these conditions up to 100 mW of average output power were provided. In addition, mode-locking of an Oxazine 750 dye laser by synchronous pumping with the cw train of pulses obtained from the Oxazine-1-Perchlorate laser is reported.     

Transform-limited behavior from the synchronously pumped cw dye laser

We report for the first time transform limited behavior from the picosecond synchronously pumped cw dye laser. This is accomplished by the use of an inexpensive, low-loss intra-cavity etalon. The Fourier relationship between pulse frequency width and time duration is shown to be obeyed quantitatively at three different wavelengths. The pulse profile changes as a function of wavelength and does not follow an analytical functionality at any wavelength studied. For each wavelength, the optical cavity length producing transform limited pulses is shown to be the same.     

YAG激光同步泵浦染料激光器产生38fs光脉冲

研究表明,不用碰撞脉冲锁模技术,而由一台简单的线型腔染料激光器,就可成功地产生短达38飞秒的光脉冲。这种激光器用六镜折叠腔,其中有Rh6G和DOPCI两个喷流和一个棱镜对色散补偿器,用连续锁模Nd:YAG激光器的倍频输出同步泵浦。染料激光脉冲的平均功率为20mW,脉冲重复频率近100MHz。     

Cavity detuning effects in the synchronously mode-locked CW dye laser

A detailed numerical model analysis of the synchronously mode-locked CW dye laser is presented. In the analysis, good mode-locking is found mainly for negative cavity detuning. The calculated cavity length detunig effects are compared with the results of experiments performed on the Oxazine-1 dye laser. The agreement between theory and experiment is satisfactory. The experimental good mode-locking regime is predicted correctly by this analysis. The present calculations are also compared with the hitherto reported qualitative model analyses with a gaussian dye pulse approximation. The validity of these model analyses is examined.     

Experimental study of a continuously pumped, actively mode-locked dye laser

Operation of a continuously pumped actively mode-locked dye laser is reported. Using a 250 MHz electrooptic modulator, a stable output of pulses as short as 10 ps has been generated. The pulse waveform has been investigated as a function of the detuning between the cavity transit time and the modulation period.     

Fluctuations in synchronously mode-locked dye lasers

We present detailed experimental data on random fluctuations of the pulse properties of a cw rhodamine 6G dye laser synchronously pumped by an acousto-optically mode-locked argon ion laser. It is shown that quantitative information about the fluctuations of the energy, the pulse repetition time and the duration of the pulses can be obtained from the power spectrum of the laser intensity which is measured with the use of an electronic spectrum analyser. This method is capable of revealing small, subpicosecond temporal pulse jitter. We show that the dye laser pulses exhibit an absolute r.m.s. jitter of 20 ps which is induced by the pump laser. The relative jitter in a dual system can be less than 1 ps because well defined correlations of the output fluctuations exist when two lasers are pumped by a common source.     

Theory of synchronously pumped dye lasers

An analysis of cw synchronously pumped dye lasers is presented. Under the assumption that the cavity (tuning element) bandwidth is much wider than the bandwidth of the transform limited pulses generated, the pulse forming dynamics is rigorously treated. It is shown that for a finite mismatch between the lengths of the dye and the pump lasers, a steady-state pulse develops in the dye laser cavity with a conserved pulseshape. The characteristics (energy, shape, peak power, duration) of these pulses of ultimate width are quantitatively determined as a function of cavity mismatch. An analytical solution for the pulse envelope is determined, which yieldsI(t)∝Sech²(t/t _p ) to a good approximation.     

Generation of synchronised ultrashort pulses using a dual wavelength synchronously mode-locked CW dye laser

The properties of a dual wavelength synchronously mode-locked cw dye laser are described. Results are presented which show that good mode-locking is obtainable under dual wavelength conditions. Cross-correlation measurements indicate that the time separation of the pulses depends on gain saturation within the dye.     

Pulse properties of a synchronously mode-locked,cavity dumped,picosecond dye laser system

A synchronously mode-locked, cavity-dumped picosecond dye laser is described. The structure and intensity of the picosecond pulses measured under different conditions are reported. It was found that the structure of the pulses from the synchronously pumped dye laser depends critically on the length of the Ar⁺ laser pulses. At the shortest Ar⁺ laser pulses of about 70 ps the dye pulses are as short as 1.1 ps. With Ar⁺ laser pulses of 200 ps the dye laser pulses contains a broad satellite pulse which contains a large fraction of the total intensity. When a cavity dumper is added to the system one gets dye laser pulses 15–20 ps long with a substructure, which indicates incomplete mode-locking. Well mode-locked 1.5–2.0 ps pulses were obtained in the red part of the dye laser action spectrum, i.e. 620–650 nm for R6G, 595–608 nm for R 110 and 657–662 nm for RB, respectively. Addition of mode-locking dyes also improved the pulse quality at some wavelengths.     

Frequency locking of a dye laser using adsorbed atoms

Frequency locking of a dye laser to atomic lines is obtained by using atoms adsorbed on an intracavity glass surface. This effect is attributed to the selective transmission of the interface due to anomalous refractive index.