Stabilization of femtosecond mode-locked Ti:sapphire laser forhigh-accuracy pulse interferometry

We propose a method of long-term stabilization of the repetition rate and the spectral envelope in a femtosecond mode-locked (fs-ML) laser pulse by a simple control method without modifying the laser cavity configuration. The effectiveness of the repetition-rate-stabilized fs-ML laser was evaluated in a long-optical-path (LOP) pulse interferometer with a short reference arm. The resulting accuracy in the LOP pulse interferometer was improved to one-seventh that of a free-running fs-ML laser. Moreover, the stabilization of the spectral envelope was estimated to suppress the fluctuation in the phase and group indices of an object under testing by 1/50, which can increase the measurement accuracy in pulse interferometry. The simple and practical stabilization method provides a means to increase the application of pulse interferometry using the fs-ML laser     

双色交叉锁模钛宝石飞秒激光器

文章报导一种能够同步输出两种独立波长脉冲的交叉锁模钛宝石飞秒激光器,两列光脉冲的中心波长和持续期分别是804nm,758nm及25fs,26fs.激光器输出的总平均功率为200mW.双波长飞秒光脉冲之间的跳动小于1fs.     

钛宝石激光飞秒和皮秒脉冲的三种工作模式

在双光束泵浦的钛宝石激光器中,实现了飞秒和皮秒脉冲的独立自锁模、交叉锁模和多脉冲3种工作模式,分析了飞秒和皮秒激光腔内的群速弥散(GVD)、自相位调制(SPM)、交叉相位调制(XPM)、增益竞争和自振幅调制(SAM)。结果表明:独立自锁模工作模式下,GVD和SPM决定了自锁模激光脉冲的特性;交叉锁模工作模式下,飞秒和皮秒脉冲具有很高的同步性,脉冲间的抖动为517 fs,飞秒和皮秒激光腔的调谐范围分别为36nm和22 nm;多脉冲工作模式下,飞秒脉冲仍然是单脉冲,而皮秒脉冲分裂为3个次脉冲,间隔为426 fs。     

磁脉冲压缩开关在钛宝石激光器中的应用分析

首次提出了将磁脉冲压缩开关应用于钛宝石激光器中,由磁脉冲压缩开关和闸流管组合作为放电开关.给出了一种新型的灯泵钛宝石激光器电源放电电路,并对磁脉冲压缩开关应用的原理及在激光器激励电路中的工作过程进行了分析.     

掺钛蓝宝石飞秒激光空间光强分布特性的测量研究

为了更好地利用飞秒激光光源,采用自行设计的光束横截面空间光强分布测量装置研究了掺钛蓝宝石飞秒激光放大系统(美国光谱物理公司)输出的40 GW飞秒激光束的空间光强分布特性.通过对测量系统精确标定及对输出光束光强分布的研究表明:飞秒放大系统输出激光束在低泵浦电流下的光斑质量较好,在高泵浦电流下光斑质量变差,并且观察到了光束横截面中心区域的光强较低泵浦电流反而减小的情况,在多通放大过程中泵浦光的光斑质量对飞秒激光束空间分布有很大影响.     

Ultrashort pulse generation from a passively mode-lockedTi:sapphire laser based system

The detailed characteristics of a passively mode-locked Ti:sapphire laser using saturable absorbers are described. This laser can stably generate nearly transform-limited sub-100-fs pulses around 780 nm. Combining this oscillator and a double-pass Ti:sapphire amplifier pumped by a CW Q-switched YAG laser (3 kHz) allows fiber-grating pulse compression down to 14 fs     

Picosecond optical pulse generation from mode-locked phased laser diode array

Actively mode-locked 26 ps optical pulses are generated from a gain-guided, 10-stripe, phased laser GaAs diode array with an external cavity consisting of two cylindrical lenses and a corner reflector. To our knowledge, this is the shortest pulse width yet demonstrated from a mode-locked phased laser diode array. The detuning bandwidth of the mode-locking is measured as 2.5 MHz.<>     

高功率超短脉冲钛宝石激光系统波前测量实验

为表征SILEX-Ⅰ超强超短脉冲钛宝石激光装置的性能,利用高空间分辨的哈特曼波前传感器实验研究了该系统的光束波前畸变特性。实验中采用俄罗斯科学院激光和信息技术研究所研制的自缩束哈特曼波前测量系统,哈特曼波前传感器的最大入射口径可达95mm,测量精度为0.08μm。得到激光脉冲在压缩前的P-V值仅为0.13λ(λ=800nm),RMS值为0.02λ;压缩后P-V值为0.63,λRMS值为0.09λ,并对实验结果进行了分析和讨论。结果表明,该激光装置具有良好的光束质量,其主要波前畸变来源于压缩池。     

Doubly resonant Ti:sapphire laser

A CW Ti:sapphire laser that operates simultaneously at two frequencies is described. This mode of operation was obtained with an intracavity dispersive prism and two separate feedback paths. An alternative means of achieving dual frequency operation was demonstrated using a birefringent filter. Repetitive Q-switching produced an increase in the range of wavelengths over which dual frequency operation was obtained     

钛宝石自锁模谐振腔研究

本文利用一种新方法研究了钛宝石自锁模谐振腔的特性 ,讨论了晶体长度 ,凹面镜焦距 ,谐振腔长度对自锁模的影响 ,获得了对谐振腔设计 ,及腔参数优化有用的结论。     

连续钛宝石激光器自锁模实验研究

用本所生长的掺钛宝石晶体和国内的元器件进行钛宝石激光器自锁模实验研究，获得了最窄脉冲宽度５３ｆｓ，谱宽１３ｕｍ，平均功率２００ｍＷ，调谐范围７５０～８５０ｎｍ的稳定激光脉冲序列。     

钛宝石激光器的多模式运转

在一台双光束泵浦的钛宝石激光器中实现了可调谐连续输出、独立自锁模、交叉锁模和多脉冲模运转式。分析了可调谐连续输出模式下两个激光腔的增益竞争,研究了飞秒和皮秒激光腔内的群速弥散、自相位调制、交叉相位调制以及自振幅调制。结果表明,可调谐连续输出模式下两个激光腔的输出主要取决于泵浦激光的功率,独立自锁模工作模式下,群速弥散和自相位调制决定了自锁模的稳定性;交叉锁模工作模式下,交叉相位调制是影响飞秒和皮秒脉冲之间同步性的主要因素。多脉冲工作模式下,脉冲自相关曲线的测量结果表明,飞秒脉冲仍然是单脉冲,而皮秒脉冲分裂为3个次脉冲。     

Fabrication of sapphire rib waveguides using a femtosecond laser

We demonstrate a method for fabricating sapphire rib waveguides with femtosecond laser micromachining technology. Finite difference beam propagation method (FD-BPM) is applied to design sapphire rib waveguides. We explore the process of etching on a sapphire substrate surface via direct laser ablation. Rib waveguides that satisfies the dimensions of our design were fabricated. Actual light propagation performance is tested, and with the cut-back method, the insertion loss of 2.9±0.5 dB/cm is measured.     

Tunable ultraviolet generation using a femtosecond 250 kHzTi:sapphire regenerative amplifier

A mode-locked Ti:sapphire regenerative amplifier system pumped with a single argon ion laser produces μJ energy femtosecond pulses of 800 nn wavelength at up to 300 kHz repetition rate. This output is used to generate tunable femtosecond pulses in the ultraviolet to as short as 240 mn by using a combination of harmonic generation, white-light continuum generation and parametric amplification. A variety of techniques to access different parts of the UV spectrum are presented     

Picosecond pulse generation in detuned distributed feedback lasers

The effect of detuning the Bragg wavelength for picosecond pulse generation in GaInAsP distributed feedback (DFB) lasers is investigated using the gain switching method. The authors have observed that the pulse width is reduced in a detuned DFB laser, in which the differential gain is enhanced through detuning the Bragg wavelength λ_B from the gain peak to a shorter wavelength by 100 Å. This result demonstrates the significance of the differential gain for short pulse generation     

Picosecond pulse response of a travelling-wave semiconductor laser amplifier

The dynamic pulse response of a travelling-wave semiconductor laser amplifier has been investigated. Peak output powers greater than 100 mW, with a fibre-to-fibre gain of 10 dB, have been observed for narrow pulses (<50ps FWHM) at low repetition rates. The dynamic bandwidth of the amplifier has been shown to be at least 50 GHz.     

Miniature, pulsed Ti:sapphire laser system

A robust, miniature Ti:sapphire laser system produces 18.4-/spl mu/J, 780-nm pulses of 700-ps duration and 0.17-nm linewidth at 8 kHz. The system is pumped by two fiber-coupled 808-nm laser diode arrays and occupies a volume of <0.5 liters. The OCIS codes are (140.3580) for solid-state lasers and (140.3480) for diode-pumped lasers.     

钛蓝宝石激光泵浦的Nd：YVO_4固体激光器

研究了用钛蓝宝石激光泵浦的Ｎｄ：ＹＶＯ４固体激光器的特性。得到基频连续激光输出功率为１９０ｍＷ，泵浦阈值为１３ｍＷ，光学斜效率为５１％。用ＫＴＰ晶体腔内倍频，得到二倍频激光输出功率为１０ｍＷ，总的光学转换效率为２．３％。给出了泵浦光波长（７４０～８３０ｕｍ）与激光输出功率之间的关系。     

Picosecond pulse generation in semiconductor lasers using resonance oscillation

Narrow pulses below 100 ps (f.w.h.m.) have been generated by applying 100 or 300 ps current pulses to a wide-stripe double heterostructure laser. The modulation current was increased to minimise the pulse width.     

多模光纤复合腔1.3μmInGaAsP激光器产生ps超短光脉冲

本文报道采用多模光纤外腔形式,从1.3μmInGaAsP激光器中产生重复频率为1GHz的1.81ps超短光脉冲的实验结果,并对实验结果进行了讨论。