共查询到20条相似文献,搜索用时 31 毫秒
1.
跨倍频程超连续光谱的产生是光学频率梳系统中测量载波包络相移频率的关键.本文采用拉锥单模光纤作为非线性光谱展宽介质, 将半导体激光(LD)抽运的掺镱硼酸钙氧钇(Yb:YCOB)振荡器输出的飞秒激光耦合到该拉锥光纤中, 通过飞秒激光在光纤中发生的相位调制、四波混频等非线性效应将光谱展宽至超过倍频程的范围.振荡器输出的飞秒激光脉冲宽度为130 fs, 中心波长为1052 nm, 重复频率为76.8 MHz, 平均功率为620 mW, 耦合进单模拉锥光纤后获得了光谱覆盖范围从550 nm至1350 nm的跨倍频程超连续光谱, 最大输出平均功率为323 mW, 耦合效率达到52%.为进一步实现全固态飞秒激光光学频率梳提供了重要基础. 相似文献
2.
Submillimeter-scale dispersion micromanagement (DMM) is used to generate coherent and stable femtosecond visible pulses in holey fibers as short as 10 mm. The longitudinal variation of the phase-matching conditions for Cerenkov radiation and four-wave mixing explains the results well. We have converted up to 20% of the total input energy to a low-noise solitary wave with a bandwidth up to 50 nm in the range 385-625 nm by using holey fibers with various DMM designs. 相似文献
3.
Rothhardt J Eidam T Hädrich S Jansen F Stutzki F Gottschall T Andersen TV Limpert J Tünnermann A 《Optics letters》2011,36(3):316-318
We present a high-average-power femtosecond laser system at 520 nm central wavelength. The laser system delivers sub-500 fs pulses with 135 W average power at a pulse repetition rate of 5.25 MHz. Excellent beam quality is provided by high power fiber amplifiers and maintained during frequency doubling, resulting in a beam quality factor of M2<1.2. To our knowledge, the system presented here is the highest average power green laser source generating femtosecond pulses with diffraction-limited beam quality. 相似文献
4.
van Howe J Lee JH Zhou S Wise F Xu C Ramachandran S Ghalmi S Yan MF 《Optics letters》2007,32(4):340-342
We demonstrate soliton self-frequency shift of more than 12% of the optical frequency in a higher-order mode solid, silica-based fiber below 1300nm. This new class of fiber shows great promise for supporting Raman-shifted solitons below 1300nm in intermediate energy regimes of 1 to 10nJ that cannot be reached by index-guided photonic crystal fibers or air-core photonic bandgap fibers. By changing the input pulse energy of 200fs pulses from 1.36 to 1.63nJ we observe Raman-shifted solitons between 1064 and 1200nm with up to 57% power conversion efficiency and compressed output pulse widths less than 50fs. Furthermore, due to the dispersion characteristics of the HOM fiber, we observe redshifted Cerenkov radiation in the normal dispersion regime for appropriately energetic input pulses. 相似文献
5.
R. Andrew Sims Pankaj Kadwani Heike Ebendorff-Heideprem Lawrence Shah Tanya M. Monro Martin Richardson 《Applied physics. B, Lasers and optics》2013,111(2):299-304
We report femtosecond pulse generation and chirped pulse amplification in Tm:fiber. A mode-locked oscillator operating in the soliton regime produced 800 fs pulses with 5 nm spectral bandwidth, at 40 pJ pulse energy. This oscillator seeded a pre-amplifier that utilizes a Raman soliton self-frequency shift to produce wavelength tunable pulses with 3 nJ energy, reduced pulse duration of 150 fs, and increased bandwidth of 30 nm. For further amplification, the pulses were stretched up to 160 ps using a chirped Bragg grating (CBG). Stretched pulses were amplified to 85 nJ after compression in single-mode Tm:fiber and recompressed with the CBG as short as 400 fs. Compressed pulses were coupled into a highly nonlinear tellurite fiber to investigate the potential of this ultrashort pulse 2-μm fiber source as a pump for mid-IR supercontinuum generation. 相似文献
6.
G. H. Kim U. Kang D. Heo V. E. Yashin A. V. Kulik E. G. Sall’ S. A. Chizhov 《Optics and Spectroscopy》2010,108(5):819-823
A femtosecond laser based on an Yb:KYW crystal with direct longitudinal pumping by a high-power semiconductor injection laser
with a fiber output is described. Femtosecond pulses were generated in the self-longitudinal-mode-locking operating condition
due to the use of a semiconductor saturable absorber. The average power of the oscillator was as high as 3.5 W at a central
wavelength of 1035 nm, the pulse length and pulse repetition rate being 200 fs and 85.5 MHz, respectively. The product of
the pulse length and the radiation spectrum width was 1.3 times higher than the theoretical limit for the pulse shape described
by the function sech2. The designed master oscillator can be also used as a stand-alone source of femtosecond radiation pulses for material microprocessing
and primary source for femtosecond laser amplification systems. 相似文献
7.
Byrd JM Hao Z Martin MC Robin DS Sannibale F Schoenlein RW Zholents AA Zolotorev MS 《Physical review letters》2006,96(16):164801
We present a new method to generate steady and tunable, coherent, broadband terahertz radiation from a relativistic electron beam modulated by a femtosecond laser. We have demonstrated this in the electron storage ring at the Advanced Light Source. Interaction of an electron beam with a femtosecond laser pulse copropagating through a wiggler modulates the electron energies within a short slice of the electron bunch with about the same duration of the laser pulse. The bunch develops a longitudinal density perturbation due to the dispersion of electron trajectories, and the resulting hole emits short pulses of temporally and spatially coherent terahertz pulses synchronized to the laser. We present measurements of the intensity and spectra of these pulses. This technique allows tremendous flexibility in shaping the terahertz pulse by appropriate modulation of the laser pulse. 相似文献
8.
Nicholson JW Ramachandran S Ghalmi S Yan MF Wisk P Monberg E Dimarcello FV 《Optics letters》2006,31(21):3191-3193
We demonstrate propagation of 14 nJ femtosecond pulses through a large-mode-area, higher-order-mode (HOM) fiber with an effective area of 2100 microm2. The pulses propagate stably in the LP07 mode of the fiber through lengths as long as 12 m. The strongly chirped pulses exiting the amplifier fiber are dechirped by the high-order-mode fiber, resulting in pulses with a peak power of 61 kW after propagation in 5 m of the positive-dispersion fiber. A small amount of self-phase modulation is observed in the compressed pulses and is described well by a nonlinear Schr?dinger equation model that takes into account the measured effective area and dispersion of the HOM fiber. 相似文献
9.
10.
Fiber based high repetition rate, high energy laser source applying chirped pulse amplification 总被引:4,自引:0,他引:4
D. Nickel A. Liem J. Limpert H. Zellmer U. Griebner S. Unger G. Korn A. Tünnermann 《Optics Communications》2001,190(1-6):309-315
We demonstrate the potential of a high-gain Yb-fiber amplifier system to provide ultrashort pulses with high energies. 100 μJ pulses generated at a repetition rate of 32 kHz exhibit nearly diffraction limited output (M2≈1.7) at a 1060 nm center wavelength. Using chirped pulse amplification, temporally streched laser pulses from a femtosecond oscillator could be compressed after amplification to subpicosecond pulse duration. The achievable intensities are high enough to create plasmas which can efficiently convert laser light to the extreme ultraviolet radiation. In a multimode Yb-doped fiber amplifier we obtained average powers of up to 22 W and single pulse energies up to 130 μJ. 相似文献
11.
We study theoretically the spectral intensity evolutions of the femtosecond Gaussian and parabolic pulses with different initial pulse energies and compare the nonlinear compressions of these pulses based on a meter-long hollow-core fiber filled with neon for different initial pulse durations. The pulses are first coupled into gas-filled hollow-core fiber for spectrum broadening, then compressed by the optimal chirp compensation. The parabolic pulse possesses a shorter pulse duration, larger peak power, and cleaner wings than Gaussian pulse. The properties are useful for compressing the pulses and thus generating the high-energy, short-duration pulses. 相似文献
12.
Tunable femtosecond laser in the visible range with an intracavity frequency-doubled optical parametric oscillator 下载免费PDF全文
We demonstrated experimentally a synchronously pumped intracavity frequency-doubled femtosecond optical parametric oscillator (OPO) using a periodically-poled lithium niobate (PPLN) as the nonlinear material in combination with a lithium triborate (LBO) as the doubling crystal. A Kerr-lens-mode-locked (KLM) Ti:sapphire oscillator at the wavelength of 790 nm was used as the pump source, which was capable of generating pulses with a duration as short as 117 fs. A tunable femtosecond laser covering the 624-672 nm range was realized by conveniently adjusting the OPO cavity length. A maximum average output power of 260 mW in the visible range was obtained at the pump power of 2.2 W, with a typical pulse duration of 205 fs assuming a sech2 pulse profile. 相似文献
13.
Fabian Weise Georg Achazi Monika Paw?owska Albrecht Lindinger 《Optics Communications》2011,284(15):3759-8626
We present an analytical concept for generating shaped femtosecond laser pulses at the distal end of a microstructured hollow core photonic crystal fiber. The properties of the fiber are analyzed and included in the shaping procedure. A parametric pulse shaping method allows for tailoring a sequence of sub-pulses. In this method, each sub-pulse can be individually controlled by its physically intuitive parameters distance in time, energy, phase and chirps as well as the state of polarization including ellipticity, orientation, and helicity. This is demonstrated with a series of double pulses, in which a single parameter is systematically varied, and additionally with more complex example pulses. Further, we investigate the impact of mechanical distortions of the fiber on the pulse shape. The presented method could be beneficially used in endoscopic applications in life sciences. 相似文献
14.
报道了一种通过预先对信号光脉冲非线性整形, 进而在光纤放大器中实现自相似演化的方法. 利用透射光栅对和普通单模光纤组成被动脉冲整形装置, 预先优化脉冲的时域宽度和光谱质量, 使脉冲在光纤放大器中快速演化到自相似子. 研究中首先通过数值模拟对比, 说明了非线性整形对脉冲实现快速自相似放大的关键作用, 提高了放大器输出脉冲质量, 减小了去啁啾脉冲宽度. 实验中, 通过优化非线性整形输出, 在2.2 m 长的掺Yb3+光纤中, 在一定抽运功率范围内均实现了脉冲自相似放大, 去啁啾后得到脉冲宽度60 fs 的变换极限脉冲输出. 这种非线性脉冲预整形方法有效减小了 自相似演化所需光纤长度, 同时降低了自相似放大对种子源质量的要求, 首次将全正色散光纤锁模激光器成功用于自相似放大, 促进了当前自相似放大系统的全光纤化.
关键词:
非线性整形
光纤放大器
自相似放大
飞秒激光 相似文献
15.
Ashkan Ghanbari Alireza Kashaninia Ali Sadr Hamed Saghaei 《Optical and Quantum Electronics》2018,50(11):411
In this paper, femtosecond optical pulses compression and supercontinuum generation in a triangular silicon photonic crystal fiber at 2500 nm are investigated. A region of large minimum anomalous group velocity dispersion, negligible higher order dispersions and unique nonlinearity of silicon are used to demonstrate compression of 100 fs initial input optical pulses to 2.5 fs and ultra-broadband supercontinuum generation with very low input pulse energy over short distances of the fiber. 相似文献
16.
We report a mode-locked ytterbium fiber laser that generates femtosecond pulses with energies as large as 2.2 nJ. This represents a 20-fold improvement in pulse energy compared with that of previously reported femtosecond Yb fiber lasers. The laser produces pulses as short as 52 fs, which are to our knowledge the shortest pulses to date from a Yb fiber laser. The laser is diode pumped by a wavelength-division multiplexing coupler, which leads to excellent stability. 相似文献
17.
Aida Esmaeilian-Marnani Ahmad Fauzi Abas Mohd Adzir Mahdi Khairulmizam Samsudin 《Optical Review》2012,19(2):71-77
Propagation of temporal 50 femtosecond pulse and pulse stream, which is realized by substituting each input pulse with reduced-order
overlapping soliton pair, is investigated through short standard single-mode fiber. For the pulse stream the initial inter-pulse
delay is selected to be 227 fs and the pulses are to be perturbed to avoid collision with the neighboring pulses. This method
reduces the pulse time delay and properly retains the amplitude despite tradeoff between these two. This is a significant
improvement in the low power femtosecond pulse and pulse stream propagation. 相似文献
18.
Distortion-free delivery of nanojoule femtosecond pulses from a Ti:sapphire laser through a hollow-core photonic crystal fiber 总被引:3,自引:0,他引:3
We demonstrate propagation of femtosecond pulses in the 800-nm range through a hollow-core photonic crystal fiber with preserved temporal and spectral profiles for pulse energies up to 4.6 nJ. Without the use of a prechirping unit, 170-fs pulses were transmitted essentially undistorted at 812 nm, near the zero-dispersion wavelength. Because of the air guidance of pulses, intensity-dependent nonlinear effects were minimal, with only 15% pulse broadening occurring at 350-mW average output power. This fiber thus is excellently suited for applications that require single-mode delivery of high-energy ultrashort pulses to the fiber output face such as, for example, miniaturized multiphoton microscopes. 相似文献
19.
Simultaneous generation of spectrally distinct third harmonics in a photonic crystal fiber 总被引:3,自引:0,他引:3
Omenetto FG Taylor AJ Moores MD Arriaga J Knight JC Wadsworth WJ Russell PS 《Optics letters》2001,26(15):1158-1160
By coupling femtosecond pulses at lambda - 1.55mum in a short length (Z - 95 cm) of photonic crystal fiber, we observe the simultaneous generation of two visible radiation components. Frequency-resolved optical gating experiments combined with analysis and modal simulations suggest that the mechanism for their generation is third-harmonic conversion of the fundamental pulse and its split Raman self-shifted component. 相似文献
20.
S. O. Konorov D. A. Akimov A. A. Ivanov M. V. Alfimov K. V. Dukel’skii A. V. Khokhlov V. S. Shevandin Yu. N. Kondrat’ev A. M. Zheltikov 《Applied physics. B, Lasers and optics》2005,80(4-5):437-439
Copropagating fundamental-wavelength and second-harmonic femtosecond pulses of Cr: forsterite laser radiation are used to study cross-phase-modulation-induced instabilities and frequency shifts in a photonic-crystal fiber. Parametric instability of the second-harmonic probe pulse induced through cross-phase modulation by the fundamental-wavelength pump pulse gives rise to distinct sidebands in the spectrum of the probe field transmitted through the fiber. The wavelength of these sidebands was tuned in our experiments within approximately 100 nm by varying the peak power and the delay time of the pump pulse, suggesting a convenient way of controlled parametric spectral transformation of ultrashort laser pulses.This revised version was published online in March 2005. In the previous version, the published online date was missing 相似文献