Stabilizing the spectrum of a femtosecond Ti:Sapphire laser

A new scheme for stabilizing the beat frequency of the interacting longitudinal modes in a femtosecond Ti:sapphire laser (Femos-1) has been developed and experimentally studied. The stability and frequency spectrum of mode beats in a modified laser have been monitored. A short-term instability of the beat frequency does not exceed 4.8 × 10^?8 (τ = 10 s) over a time scale of 10 min. The laser linewidth in the regime of self-mode-locking is ≤3 Hz at a laser spectrum width of 20 nm.     

Self-seeded Ti: Sapphire laser with an active feedback mirror

Abstract

A single-longitudinal mode (SLM) dual-cavity pulsed Ti:sapphire laser is presented. It is self-seeded by means of an active feedback mirror (AFM) consisting of a partially reflecting mirror and additional active medium. The use of AFM results in an increase of both the laser output energy and overall conversion efficiency by a factor of about 1.4 compared to results achieved with a passive feedback mirror, under equivalent conditions. A reliable, temporally stable SLM regime of operation is achieved in the 740–820 nm spectral range.     

Wavelength-tunable optical short-pulse generation by mutual pulse injection seeding of two gain-switched Fabry-Perot laser diodes

A simple and robust system is presented to generate wavelength-tunable optical short pulses by use of two gain-switched Fabry-Perot laser diodes in a mutual pulse injection-seeding scheme. The operating wavelength of the optical pulses is flexibly selected by adjustment of a tunable filter, and its intensity is enhanced with an erbium-doped fiber amplifier. The side-mode suppression ratio achieved by the system is larger than 26 dB over a wavelength region of 25 nm and higher than 31 dB within an 18-nm wavelength.     

Generation of Fourier-transform-limited 35-ns pulses with a ramp-hold-fire seeding technique in a Ti:sapphire laser

We report on an injection-seeded Ti:sapphire laser pumped by the second harmonic of a Nd:YAG laser. The resonance between the low-power seed laser and the slave cavity is achieved by a ramp-hold-fire technique. Because of the triangular cavity design, the spatial beam profile is excellent; and combined with the narrow-linewidth pulses, the conversion efficiencies for nonlinear frequency generation are excellent.     

水热法生长复合钛宝石激光晶体

水热法生长了复合钛宝石(Al₂O₃/Ti:Al₂O₃)激光晶体.对外层Al₂O₃X射线ω扫描表明其晶体质量很高.外层生长的Al₂O₃和内部的钛宝石激光棒结合牢固、紧密,因而能适应高强度泵浦所带来的激光介质内部的热应力.复合激光晶体界面层带来的光损耗很小.就我们所知,这是首次用水热法生长复合激光晶体.     

超宽谱钛宝石飞秒激光器的研究进展

超宽谱钛宝石飞秒激光器的出现是近年来飞秒激光技术的重要进展之一.文章对近年来国际上出现的几种主要的钛宝石超宽谱飞秒激光器的原理、结构及优缺点进行了介绍,给出了其发展趋势.     

Tunable picosecond blue and ultraviolet pulses from a diode-pumped laser system seeded by a gain-switched laser diode

Picosecond pulses emitted from a gain-switched laser diode have been amplified in a Ti:sapphire regenerative amplifier indirectly pumped by a 4-W laser diode. This all-solid-state system produced microjoule pulses tunable from 803 to 840 nm at repetition rates up to 25 kHz with durations of 70-100 ps. By frequency doubling and tripling the output, we generated blue and UV pulses tunable from 401 to 420 nm and from 268 to 280 nm, respectively. Average powers larger than 4 mW were reached in these two wavelength regions.     

抽运条件对Nd:YVO4增益开关激光器输出特性的影响

通过数值求解增益开关速率方程,模拟得到Nd:YVO4增益开关激光器输出脉宽和峰值功率随抽运条件的理论变化曲线,在此基础上提出了减小增益开关固体激光器输出脉宽的方法,即:令抽运源LD的直流驱动电流接近阈值,叠加脉冲电流高于2倍阈值,并调节抽运脉宽保证单脉冲激光输出。实验结果与理论曲线符合较好,证实了这一方法的有效性。利用此方法最终获得了脉宽20ns、重复频率在1Hz-4kHz精确可控的1.064μm脉冲激光输出。     

Femtosecond Ti:Sapphire Oscillator Electro-Optically Cavity Dumped at 50 kHz

Use of a transverse KD?P Pockels cell and novel low-loss sapphire Rochon polarizer to cavity dump a hard-aperture, Kerr-lens mode-locked, Ti:sapphire oscillator is demonstrated. High-quality 90-fs pulses with energies of ~50 nJ at repetition rates of up to 50 kHz were obtained.     

Ti: Sapphire Pumped Femtosecond Optical Parametric Oscillator Exhibiting Soliton Formation

Abstract

The configuration and operation of a singly resonant Ti: sapphire pumped optical parametric oscillator (OPO) based on KTP is discussed. Cavity arrangements with and without dispersion compensation are described and the generation of sub-40 fs transform-limited pulses is highlighted. Evidence for soliton pulse formation in the OPO is presented and good quantitative agreement with existing theory is implied. Results of amplitude and phase noise measurements of the OPO are given and compared with those of the pump laser. Generation of pulses at several visible wavelengths by non-phase-matched processes is also briefly discussed.     

Diode-laser-pumped Nd:YAG laser injection seeding system

We have designed and tested a compact injection seeding system consisting of a diode-laser-pumped Nd:YAG master oscillator and a permanent-magnet Faraday isolator. With active resonator frequency stabilization, this system permits highly reliable single-axial-mode operation of a Q-switched Nd:YAG laser over a period of hours. The system is capable of injection seeding both stable and unstable resonator designs and is suitable for injection seeding commercial lasers with only minor modifications.     

冷却钛蓝宝石晶体低温恒温器的设计与实验研究

针对一泵浦功率为100 W的钛蓝宝石激光器设计、制造了一套液氮低温恒温器.介绍了恒温器的主要特点,通过实验测量了恒温器的静态热负荷和冷板的温度特性,并验证了该恒温器能够很好的满足钛蓝宝石晶体的低温冷却要求.     

Optical homogeneity of Ti:Sapphire crystals grown by horizontal directional solidification

We have found conditions for the growth of Ti:sapphire crystals with a uniform dopant profile by horizontal directional solidification (HDS) in protective gaseous atmospheres of different compositions at different pressures. The results demonstrate that the HDS process enables the growth of large Ti:sapphire laser crystals with high optical homogeneity and wavefront distortions in the range ??/10 to ??/5.     

Operation of a Ti:sapphire laser pumped by a 499-nm green laser

We report, for the first time, to our knowledge, the operation of a tunable Ti:sapphire laser pumped by a third-order Raman XeCl-H(2) laser system at 499 nm with a 60-ns pulse duration. The slope efficiency is 59% for this laser, producing pulses of 20-ns duration. The highest conversion-energy efficiency obtained is 41%, with an output energy of 1.2 mJ. The tuning range for a single set of cavity mirrors is 680-834 nm and is limited mainly by the mirror reflectivity. This study shows that a combined laser system based on a XeCl excimer laser can offer wavelength diversity.     

Growth of large Ti:Sapphire crystals by horizontal directional solidification in argon atmosphere

We report the growth of large (110 × 200 × 50 mm) titanium-doped sapphire crystals by horizontal directional solidification in a protective atmosphere and their lasing characteristics. The crystals are shown to be suitable for the fabrication of lasing elements with a figure of merit above 150 and wavefront distortion within λ/6.     

Sequence lasing in a gain-switched Yb3+,Er(3+)-doped silica double-clad fiber laser

Experimental results relating to the gain-switched operation of a double-clad Yb3+,Er(3+)-doped silica fiber laser that is pulse pumped with the output from a flash-lamp-pumped Ti:sapphire laser are presented. For all the configurations of the fiber laser that we studied, the 2F5/2-->2F7/2 laser transition of the Yb3+ ion lased prior to laser emission from the 4I13/2-->4I15/2 transition of the Er3+ ion. To the best of our knowledge, this is the first reported operation of sequence lasing in the Yb3+,Er(3+)-codoped system. This succession of laser pulses deduced from the measurements of this investigation is a consequence of both the short intense pump pulse and the short 900-nm wavelength of the pump that does not overlap with any important excited-state absorption transitions. We believe that the predominant interionic interaction during the course of the pump pulse is the double-energy transfer to the Er3+ ion acting twice from the 2F5/2 energy level of the Yb3+ donor ion. A maximum total output of 1.65 mJ is obtained (1.38 mJ from the 2F5/2-->2F7/2 transition of Yb3+ and 0.27 mJ from the 4I13/2-->4I15/2 transition of Er3+) from a nonoptimized configuration of the fiber laser. The wavelength of the output from the fiber laser was measured to vary approximately linearly with fiber length from 1040 to 1046 nm for the Yb(3+)-based laser and 1535 to 1541 nm for the Er(3+)-based laser.     

Self-seeding of a pulsed double-grating Ti:sapphire laser oscillator

A self-seeded pulsed double-grating Ti:sapphire laser oscillator consisting of a grazing incidence cavity geometry with a pair of gratings and a standing-wave cavity pumped by a frequency-doubled Nd:YAG laser was developed and characterized. With self-seeding, narrow-linewidth single-longitudinal-mode (SLM) operation and SLM scanning were possible with a reduced lasing threshold, which was desirable for the intended applications.     

Ti:Al2O3 laser pumped by radiation from a copper-vapor laser

A scheme enabling spatial matching of copper-vapor laser radiation, which pumps a mode of an Al₂O₃:Ti laser cavity, has been developed and implemented. It is shown that copper vapor lasers as pump sources for titanium-sapphire lasers are fully capable of competing with conventional pump sources. Pis’ma Zh. Tekh. Fiz. 25, 6–11 (September 26, 1999)     

Low-threshold self-starting femtosecond Ti:sapphire laser

A low-threshold self-starting Kerr-lens mode-locked Ti:sapphire laser is demonstrated that uses a tight-focusing cavity design in conjunction with a semiconductor saturable-absorber mirror (SESAM). With 3% and 12% output couplers, we achieve mode-locking thresholds as low as 390 and 600 mW, respectively. Stable femtosecond laser pulses with average power of 114 mW are generated at a pump power of 1.2 W, which corresponds to a typical duration of 17 fs and bandwidth of 47 nm. Mode-locking operation is achieved in a pump power range of 600 mW to 4.8 W at an output coupling of 12%; the advantages of using a SESAM for low-power mode-locking operation are demonstrated.