飞秒钛宝石激光器Kerr透镜锁模动态的特性研究

研究了Kerr透镜锁模钛宝石激光器中腔内群色散改变时脉冲的动态特性。实验研究了腔内群色散改变时输出脉冲的频谱、中心波长以及脉宽的变化规律;观测和解释了脉冲频谱的双峰结构;给出了脉冲宽度与腔内色散的具体关系式;获得了最短为14.6fs的自锁模脉冲     

Mode-locking at very high repetition rates more than terahertz inpassively mode-locked distributed-Bragg-reflector laser diodes

We propose a technique for achieving mode-locking at very high repetition rates more than terahertz with high output power using a distributed-Bragg-reflector (DBR) laser, including an intracavity saturable absorber. This method is based on harmonic passive mode-locking at high gain levels and the selectivity of harmonic numbers related to the spectrum-filtering property of the intracavity Bragg reflector. Transform-limited pulses at repetition rates from 500 GHz to 1.54 THz were generated with an output power exceeding 15 mW. We studied stability of harmonic pulses by using conventional self-consistent mode-locking equations. We also discuss the effect of the spectrum-filtering properties of the intracavity Bragg reflector to the characteristics of mode-locked pulses     

利用腔内位相调制改善固体激光器的光束质量

提出一种新的利用腔内位相调制的方法来改善激光器输出的光束质量。位相调制用铌酸锂 (LiNbO3 )电光晶体实现 ,所用激光器为连续氪灯抽运的Nd∶YAG激光器。实验结果表明 ,利用腔内位相调制的方法 ,可以有效地使多模激光变为具有均匀光强分布的近基模光束     

Picosecond pulse measurements using the active laser medium

A simple method for measuring the pulse lengths of synchronously pumped dye lasers which does not require the use of an external nonlinear medium, such as a doubling crystal or two-photon fluorescence cell, to autocorrelate the pulses is discussed. The technique involves feeding the laser pulses back into the dye jet, thus correlating the output pulses with the intracavity pulses to obtain pulse length signatures in the resulting time-averaged laser power. Experimental measurements were performed using a rhodamine 6G dye laser pumped by a mode-locked frequency-doubled Nd:YAG laser. The results agree well with numerical computations, and the method proves effective in determining lengths of picosecond laser pulses     

An intracavity 16-μm Raman laser: a theoretical investigation

A theoretical model describing the dynamics of an intracavity 16-μm laser was developed. This laser consists of a TEA-CO₂ laser with an intracavity Raman cell. The Raman medium could be either hydrogen or deuterium, depending on the required wavelength. Stokes, anti-Stokes, and pump coupling were considered. Output energies as well as pulse shapes were calculated. Optimum output coupling was also determined. The model predicted that the intracavity Raman laser could be a viable alternative to a conventional multipass Raman cell for generating intense 16-μm pulses     

Subpicosecond pulse generation from erbium doped fibre laser

The generation of 900 fs pulses directly from an erbium doped fibre laser using a phase modulation technique is reported. Control of the intracavity dispersion enabled the production of pedestal-free pulses.<>     

Degenerate four-wave mixing of picosecond pulses in the saturable amplification of a dye laser

We demonstrate intracavity degenerate four-wave mixing in the saturable gain medium of a dye laser. The dye laser is a synchronously pumped bidirectional ring laser that produces pulses of 4 ps duration. The dynamics of the interaction provides information on the phase coherence of the pulses. A simple theory of transient degenerate four-wave mixing is presented that accurately describes the measurements.     

Characterization of nonlinear switching in a figure-of-eight fiberlaser using frequency-resolved optical gating

The measurement technique of frequency-resolved optical gating is applied to determine the nonlinear switching characteristics of a passively modelocked figure-of-eight erbium-doped fiber laser. By completely characterizing the intensity and phase of the laser output pulses, the intracavity fields in the nonlinear amplifying loop mirror of the laser cavity are determined by numerical propagation using the nonlinear Schrodinger equation. Excellent switching of 95% can be achieved as a result of uniform phase characteristics developed by pulses propagating in the nonlinear amplifying loop mirror     

碰撞锁模染料激光器中激光脉冲的啁啾特性及其色散补偿

从实验上研究了碰撞锁模染料激光器中激光脉冲的啁啾性质.分析了采用两块棱镜组成的棱镜对进行内腔补偿时,棱镜对的色散对输出激光脉冲的宽度、稳定性及光谱特性的影响.     

Carrier-frequency-controlled gigabit pulse generation with a Nd3+: YAG laser

Optical pulses up to 1.25 Gbit/s were obtained with a Nd³⁺:YAG laser by multiple mode locking. The carrier frequency of mode-locked pulses was tuned through several tens of gigahertz by tilting an intracavity tuning etalon. Some detuning effects in forced mode locking will be also presented.     

Theory of intracavity frequency doubling in passively mode-lockedfemtosecond lasers

The authors construct a quantitative theoretical model of an intracavity frequency-doubled and passively mode-locked laser, supported by experimental observations with a colliding pulse mode-locked femtosecond dye laser. The major findings are that for second-harmonic conversion efficiencies consistent with continuing laser operation (<5%): (1) a stable mode-locking regime always exists, although it narrows somewhat with increasing conversion efficiency; and (2) the duration of the fundamental pulses can always be preserved, even in the femtosecond time domain, by readjusting saturable gain and saturable loss under the same conditions. Both the model and observations contrast with previous studies of actively mode-locked and synchronously mode-locked lasers containing intracavity frequency-doubling crystals     

Mode-locked flashlamp-pumped coumarin dye laser at 4600 Å

A flashlamp-pumped coumarin dye laser mode-locked by means of intracavity loss modulation has produced subnanosecond, millijoule pulses suitable for pumping other dye lasers or for application to fast photochemical reaction studies.     

自锁模Ti:Al_2O_3激光器腔内脉冲双向啁啾补偿

研究了腔内脉冲双向啁啾补偿方法,实现了Ti:Al_2O_3激光器稳定的低泵浦自锁模运转,将Ar~ 激光泵浦功率降低到2.4W,获得了220mW,36 fs的锁模脉冲输出.     

不同激光脉冲驱动的尾场中正电子加速的研究

为了研究在激光驱动的尾场中被加速正电子的动能,采用数值模拟方法,得到了非对称sine脉冲、flat-top脉冲和Gaussian脉冲驱动的尾场中被加速的正电子的能量。结果表明,非对称sine脉冲驱动尾场中正电子得到的能量比flat-top脉冲和Gaussian脉冲驱动尾场中得到的能量高一些。     

Ultrashort pulse generation by intracavity spectral shaping andphase compensation of external-cavity modelocked semiconductor lasers

Intracavity spectral shaping and external chirp compensation techniques were employed to generate nearly transform-limited optical pulses with a temporal duration of 250 fs from an external-cavity modelocked semiconductor laser. It was also demonstrated that intracavity spectral shaping techniques can be used for artificially tailoring the chirp of the output pulses     

对称和非对称激光尾场中被加速正电子的研究

为了研究在激光驱动的尾场中被加速正电子的动能,采用数值模拟方法,得到了在对称高斯脉冲和非对称高斯脉冲驱动的尾波场中被加速的正电子的能埴.结果表明,非对称高斯脉冲驱动尾场中的正电子的能量比对称高斯脉冲驱动尾场中的正电子的能最高.     

Colliding pulse mode-locked laser

The fabrication and performance of a colliding pulse-mode locked laser with an intracavity saturable absorber is described. The laser has a threshold current of 65 mA and differential efficiency of 0.04 mW/mA when coupled into a single-mode fiber. Mode-locked pulses with ~1 ps pulse width at ~10 GHz has been obtained     

Chirped pulse amplification of 300 fs pulses in an alexandriteregenerative amplifier

The amplification of femtosecond dye laser pulses up to the 3.5-mJ level in an alexandrite regenerative amplifier is discussed. An expansion/compression system using diffraction gratings allows chirped amplification techniques to be used to produce peak powers upwards of 1 GW. Limitations in the chirped pulse amplification of ultrashort pulses due to intracavity dispersive elements are discussed     

脉冲主动锁模和主被动锁模激光器

本文报导了脉冲式主动、主被动锁模磷酸盐玻璃振荡器的特性.主动锁模的脉冲宽度为200微微秒左右,输出性能比较稳定.对于输出脉宽为7微微秒左右的主被动锁模,出现卫星脉冲的几率与调制器的调制系数有关.使用不同的腔内标准具能产生30微微秒和70微微秒的脉冲,没有观察到卫星脉冲.主被动锁模的性能比被动锁模有所提高.