共查询到20条相似文献,搜索用时 15 毫秒
1.
We demonstrate an order-of-magnitude energy scaling of a white-light seeded noncollinear optical parametric amplifier in the visible. The generated pulses, tunable between 520 and 650 nm with sub-25-fs duration, had energies up to 310 microJ with 20% blue-pump-to-signal energy conversion efficiency at 540 nm. This new ultrafast source will make possible numerous extreme nonlinear optics applications. As a first application, we demonstrate the generation of tunable vacuum ultraviolet pulses. 相似文献
2.
R. A. Ganeev G. S. Boltaev R. I. Tugushev T. Usmanov M. Baba H. Kuroda 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2011,64(1):109-114
Third- and higher-order nonlinear optical processes in fullerenes were studies to define
the influence of low-order nonlinearities on the high-order harmonic generation in these
media. We measured the nonlinear absorption coefficients of the C60:toluene
solution using the 532 and 1064 nm, 50 ps pulses. The high-order harmonic generation was
studied during propagation of the 790 nm, 150 fs pulses through the plasmas produced on
surfaces containing fullerene powder. These studies have shown that the low-order
nonlinearities of fullerenes have no impact on the generation of harmonics in such mediums
in the vacuum ultraviolet range at optimal intensity of laser radiation. 相似文献
3.
De Ninno G Allaria E Coreno M Curbis F Danailov MB Karantzoulis E Locatelli A Menteş TO Nino MA Spezzani C Trovò M 《Physical review letters》2008,101(5):053902
We demonstrate for the first time that seeded harmonic generation on electron storage rings can produce coherent optical pulses in the vacuum ultraviolet spectral range. The experiment is performed at Elettra, where coherent pulses are generated at 132 nm, with a duration of about 100 fs. The light source has a repetition rate of 1 kHz and adjustable polarization; it is very bright, with a peak power several orders of magnitude above that of spontaneous synchrotron radiation. Owing to high stability, the source is used in a test photoemission electron microscopy experiment. We anticipate that seeded harmonic generation on storage rings can lead to unprecedented developments in time-resolved femtosecond spectroscopy and microscopy. 相似文献
4.
Selle R Nuernberger P Langhojer F Dimler F Fechner S Gerber G Brixner T 《Optics letters》2008,33(8):803-805
We experimentally demonstrate the generation and characterization of polarization-shaped femtosecond laser pulses in the ultraviolet at a central wavelength of 400 nm. Near-infrared laser pulses are first polarization shaped and then frequency doubled in an interferometrically stable setup that employs two perpendicularly oriented nonlinear crystals. A new pulse shaper design involving volume phase holographic gratings reduces losses and hence leads to an increase in pulse energy. 相似文献
5.
We demonstrate the generation of phase-coherent frequency combs in the vacuum utraviolet spectral region. The output from a mode-locked laser is stabilized to a femtosecond enhancement cavity with a gas jet at the intracavity focus. The resulting high-peak power of the intracavity pulse enables efficient high-harmonic generation by utilizing the full repetition rate of the laser. Optical-heterodyne-based measurements reveal that the coherent frequency comb structure of the original laser is fully preserved in the high-harmonic generation process. These results open the door for precision frequency metrology at extreme ultraviolet wavelengths and permit the efficient generation of phase-coherent high-order harmonics using only a standard laser oscillator without active amplification of single pulses. 相似文献
6.
利用1.064μm基频超短脉冲激光,使用光学二次谐波方法研究了超高真空中蒸镀在多晶银表面上的C60薄膜紫外光照射下的光聚合现象,发现聚合以后的C60二阶非线性响应增强,同时观察到光聚合的饱和效应,C60光聚合二阶非线性的提高可以用电四极了磁偶极子对二次谐波贡献的增强来解释。 相似文献
7.
Nomura Y Ito Y Ozawa A Wang X Chen C Shin S Watanabe S Kobayashi Y 《Optics letters》2011,36(10):1758-1760
We present a quasi-cw laser in a vacuum ultraviolet region at megahertz repetition rate. The narrowband pulses generated from an ytterbium-fiber laser system at 33 MHz repetition rate at the central wavelength of 1074 nm are frequency-converted by successive stages of LiB(3)O(5) crystals and KBe(2)BO(3)F(2) crystals. The generated radiation at 153 nm has the shortest wavelength achieved through phase-matched frequency conversion processes in nonlinear optical crystals to our knowledge. 相似文献
8.
真空紫外超短脉冲激光具有波长短、单光子能量高、脉宽小等特点,在飞秒化学以及超快动力学等方面具有相当广泛的应用前景.由于直接利用受激辐射获得真空紫外超短脉冲是相当困难,因此利用非线性频率转换技术,超短脉冲与惰性气体相互作用,将红外、可见或紫外光波段的超短脉冲转换到真空紫外波段是目前获得紫外超短脉冲最快捷有效的方式.围绕真空紫外超短脉冲的产生及其在超短动力学中应用展开,介绍了产生真空紫外超短脉冲的高斯谐波、空心光纤四波混频和光丝四波混频的方法,对其优缺点作了评述,并对真空紫外超短脉冲激光在超快动力学过程中的应用进行了简单的总结. 相似文献
9.
P. Nuernberger G. Vogt R. Selle S. Fechner T. Brixner G. Gerber 《Applied physics. B, Lasers and optics》2007,88(4):519-526
We experimentally demonstrate a method to generate shaped femtosecond laser pulses in the ultraviolet at a central wavelength
of 267 nm, the third harmonic of conventional titanium-sapphire femtosecond laser systems. Employing a 128-pixel liquid-crystal
spatial light modulator, we impose variable spectral phase modulations upon the near-infrared laser pulses. By this, complex
laser pulses can be shaped whose overall spectrum is still conserved. Our experiments show that it is possible to easily transfer
these pulses into the ultraviolet at 267 nm via sum-frequency mixing in nonlinear crystals and to predictably generate multistructured
ultraviolet femtosecond laser pulses. We analyze the temporal and spectral composition of these pulses after frequency conversion
into the ultraviolet using difference-frequency cross-correlation and XFROG (cross-correlation frequency-resolved optical
gating) techniques with an unmodulated fundamental laser pulse. The method can be employed to facilitate adaptive quantum
control experiments in the ultraviolet wavelength regime, where the major absorption bands of many organic molecular systems
are located.
PACS 42.65.Re; 42.72.Bj; 32.80.Qk 相似文献
10.
M. Spanner M. Pshenichnikov V. Olvo M. Ivanov 《Applied physics. B, Lasers and optics》2003,77(2-3):329-336
We describe the virtues of the pump–probe approach for controlled supercontinuum generation in nonlinear media, using the example of pulse compression by cross-phase modulation in dielectrics. Optimization of a strong (pump) pulse and a weak (probe) pulse at the input into the medium opens the route to effective control of the supercontinuum phases at the output. We present an approximate semi-analytical approach which describes nonlinear transformation of the input pulse into the output pulse. It shows how the input and the output chirps are connected via a time-warp transformation which is almost independent of the shape of the probe pulse. We then show how this transformation can be used to optimize the supercontinuum generation to produce nearly single-cycle pulses tunable from mid-infrared to ultraviolet. PACS 42.65.Re; 42.65.Ky 相似文献
11.
A numerical simulation of attosecond harmonic pulse generation in a three-dimensional field-ionizing gas is presented. Calculated harmonic efficiencies quantitatively reproduce experimental findings. This allows a quantitative characterization of attosecond pulse generation revealing information currently not accessible by experiment. The rapid phase variation and spatiotemporal distortions of harmonics are smaller than anticipated, allowing focusing of 30-nm, 750-as pulses to intensities in excess of 10(13) W/cm(2). Feasibility of such pulses brings novel applications such as extreme ultraviolet nonlinear optics and attosecond pump probe spectroscopy within reach. 相似文献
12.
I.V. Borgun N.A. Azarenkov A. Hassanein A.F. Tseluyko V.I. Maslov D.L. Ryabchikov 《Physics letters. A》2013,377(3-4):307-309
Generation of high-power pulses of extreme ultraviolet radiation from multi-charged tin plasma is of great interest to many applications. We studied the electric potential distribution in the discharge gap in kind of the electric double layer and its effect on the extreme ultraviolet generation. The local plasma heating by electron beam, formed in the double layer, leads to generation of peak radiation pulses and as a result to an increase in the radiation power. 相似文献
13.
An intracavity frequency-doubling scheme was merged with an actively mode-locked AlGaInP laser diode with an external cavity to provide efficient generation of 335-nm ultraviolet light. Intense pulses of <16ps were successfully generated inside the cavity at subgigahertz repetition frequencies. We applied those pulses to intracavity second-harmonic generation from a 5-mm-long LiIO(3) crystal, which resulted in average ultraviolet power of 70muW for an average fundamental power of 73 mW. 相似文献
14.
Quantum electrodynamics (QED) predicts that electromagnetic fields interact with each other in vacuum. We study the possibility of revealing this interaction experimentally with intensities on the order of 1024–1026 W/cm2, which may be available in the next generation of laser systems. In particular, we investigate high-order harmonic generation in vacuum via the collision of two ultrastrong counterpropagating laser pulses. The experimental feasibility of the related process of stimulated light-by-light scattering is also examined. Finally, the importance of including diffractive effects to describe the nonlinear interaction between an x-ray probe and a strong, focused optical standing wave is pointed out. 相似文献
15.
We report the generation of shaped tunable ultrashort ultraviolet pulses with full control over the spectral phase and amplitude. The output of a noncollinearly phase-matched optical parametric amplifier is shaped in phase and amplitude by a liquid-crystal spatial light modulator. The resulting structured visible pulses are transferred into the ultraviolet by sum-frequency mixing with strongly chirped 775 nm pulses. Single, double, and triple pulses at 344 nm with subpulses as short as 19 fs are explicitly demonstrated. The method can easily be adapted to arbitrarily shaped pulses throughout the 295-370 nm range. 相似文献
16.
Z. Bialynicka-Birula 《Physica D: Nonlinear Phenomena》1981,2(3):513-524
The nonlinear effects like the higher harmonics generation, the amplitude-dependent change of the wavelength, the change of the shape of the pulses, were predicted for the propagation of plane electromagnetic waves in vacuum in the presence of a constant magnetic field. To solve the set of the first order nonlinear partial differential equations, the method of the “simple waves”, invented for fluid dynamics, was used. 相似文献
17.
The generation of pulsed squeezed light using an optical parametric oscillator (OPO) is discussed. This mode-locked optical parametric oscillator consists of a nonlinear crystal in a cavity which is resonant for both signal and idler waves and which is synchronously pumped by the second-harmonic of an acousto-optically mode-locked cw Nd: YAG laser. The fundamental wavelength of the pump laser provides local oscillator pulses for balanced homodyne detection of squeezed vacuum pulses emitted by the oscillator when operated below oscillation threshold. Photocurrent noise reduction to 30% below the classical shot-noise limit is observed, corresponding to squeezing of the field to a level approximately a factor of two below the mean square vacuum noise. 相似文献
18.
Nanoparticles were synthesized by irradiating a nickel target with femtosecond laser pulses in high vacuum, and subsequently analyzed. The proof-of-principle experiments aim to modify the size characteristics of the produced nanoparticles. For nickel it is found that: (i) ultraviolet laser pulses lead to a remarkable change in the nanoparticles size distribution with respect to visible laser pulses; (ii) irradiation of the femtosecond pulses induced ablation plume with a second, delayed ultraviolet laser pulse can change the size characteristics of the produced nanoparticles. 相似文献
19.
Ultraviolet pulses with a duration of 7 fs are efficiently generated by frequency doubling the output of a noncollinear optical parametric amplifier. The ultraviolet pulses are tunable between 275 to 335 nm. The acceptance bandwidth of the doubling crystal is increased by a factor of 80 through high-order achromatic phase matching. The chirp of the visible pulses and the dispersion introduced along the beam path are compensated partially before and partially after the doubling crystal. For the design of the dispersion management, we investigate the second harmonic generation of pulses with mixed orders of chirp and explicitly discuss the transfer of the spectral phase in frequency doubling. A simple analytic theory is derived that correctly describes frequently observed spectral narrowing effects. We find that chirped SHG avoids spectral narrowing and allows for precompression of dispersion encountered in the ultraviolet beam path. We apply chirped SHG to generate 18.7 fs ultraviolet pulses in an extremely simple setup. PACS 42.65.Re; 42.65.Ky; 42.65.Yj 相似文献
20.
Masahito Katto Kazuyoshi Oda Atsushi Yokotani Noriaki Miyanaga 《Optics Communications》2010,283(3):414-416
Subpicosecond vacuum ultraviolet (VUV) pulses at the wavelength of 126 nm have been generated in rare gases as a result of the 7th harmonic radiation of a subpicosecond Ti:Sapphire laser oscillating at 882 nm. The VUV harmonic intensity was optimized in Xe at the pressure of 1.2 Torr. The behavior of the harmonic emission was qualitatively reproduced by the classical nonlinear optics. The increase of the harmonic intensity was limited by multiphoton ionization of Xe. 相似文献