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 共查询到10条相似文献,搜索用时 62 毫秒
1.
To address few-shot pulse contrast measurement, we present a correlator coupling the high gain of an optical parametric amplification scheme with large pulse tilt. This combination enables a low sensitivity charge coupled device (CCD) to observe features in the pulse intensity within a 50 ps single-shot window with inter-window dynamic range >107 and <0.5 mJ input energy. We also consider use of optical densities to boost the CCD dynamic range within a single temporal window.  相似文献   

2.
Ma J  Yuan P  Wang Y  Zhang D  Zhu H  Qian L 《Optics letters》2011,36(6):978-980
We present a single-shot cross-correlating scheme capable of high dynamic range and large temporal window for pulse contrast characterization. By adopting a long-wavelength sampling pulse parametrically converted from the pulse under test, wavelength combination in the correlating process allows the use of a large noncollinear phase-matching angle in periodically poled lithium niobate crystal, matches the high-sensitivity detection system consisting of a fiber array and a photomultiplier tube, and favors the elimination of optical scattering noise. The prototype experiments demonstrate a detectable contrast maximum up to ~10(9), temporal window of ~50?ps, and resolution of ~1?ps, using <0.5?mJ input energy.  相似文献   

3.
This paper presents an experimental technique for measurement of the contrast ratio of ultrashort UV pulses. As a multiple-shot device based on the scheme of difference frequency generation this is, to our knowledge, the only cross correlator in the UV so far, which offers a dynamic range of 107 and operates with input pulse energies as low as 5 μJ. By changing the cross correlator into single-shot mode, the temporal shape of the UV pulse can be measured. Received: 26 October 1998 / Revised version: 13 January 1998 / Published online: 28 April 1999  相似文献   

4.
Three-dimensional dissection of a single actin stress fiber in a living cell was performed based on multi-photon absorption of a focused femtosecond laser pulse. The realignment process of an actin stress fiber was investigated after its direct cutting by a single-shot femtosecond laser pulse irradiation by high-speed transmission and fluorescence imaging methods. It was confirmed that mechanical force led by the femtosecond laser cutting propagates to entire cell through the cytockelton in a 100 μs time scale. The cut actin stress fiber was realigned in the time scale of a few tens of minutes. The dynamic analysis of the realignment induced by single-shot femtosecond laser gives new information on cell activity.  相似文献   

5.
Single- and multiple-shot damage thresholds and plasma-emission thresholds for fused silica and CaF2 are reported for 790 nm photons as a function of laser pulse width (190 fs – 4.5 ps). The results are compared with single-shot plasma-emission measurements [1] and with multiple-shot damage measurements [2]. Both the damage threshold and the plasma-emission threshold are shown to decrease with decreasing pulse width over the entire pulse-width range investigated.  相似文献   

6.
Panasenko D  Fainman Y 《Optics letters》2002,27(16):1475-1477
We present an experimental technique capable of single-shot recording of an ultrashort laser pulse sonogram by use of two-photon absorption in a conventional silicon CCD camera. The quadratic spectral phase, introduced into a 100-fs pulse by a grating stretcher, was measured and found to be in good agreement with the analytically calculated value. The nonlinear response of silicon allows sonogram characterization in a wavelength range from 1 to 2 mum .  相似文献   

7.
We studied the optical scattering noise, measurement artifacts, and their suppression in single-shot measurements of prepulse contrast. The measurement noise due to air scattering and the two kinds of measurement artifacts resulting from multiple reflections of the generated correlation signal and correlation between the pulse under test and the internally reflected sampling pulse were experimentally explored. The scattering noise and measurement artifacts significantly degrade the measurement fidelity. We demonstrate the clean measurement of prepulse contrast in a single-shot cross-correlator by attenuating the main peak of the correlation beam with a dot mirror and designing the correlating process based on a periodically-poled lithium niobate crystal embedded in an unpoled wafer. The standard time-scanning measurements of pulse contrast are also performed to confirm the experimental results of our single-shot measurement.  相似文献   

8.
Cléon G  Stepowski D  Cessou A 《Optics letters》2007,32(22):3290-3292
The use of a 100 ns pulse Nd:YAG laser is proposed to perform single-shot measurements by spontaneous Raman scattering. The long pulse duration is obtained thanks to a White cell placed inside the laser oscillator. This lengthens the pulse duration within the laser cavity, keeping almost the same beam quality as standard Nd:YAG lasers. The laser system is described, the advantages are compared with extra-cavity stretched lasers, and single-shot measurement of concentration in gas is demonstrated.  相似文献   

9.
An all-reflective self-referenced spectral interferometry based on the transient grating(TG)effect is proposed for single-shot measuring of the amplitude and phase of ultrashort pulses in a broadband spectral range.Except for a thin third-order nonlinear medium,which was used to generate the TG signal,no transmitted optics were used in the proposed device,and few-cycle pulses in a broad spectral range from deep UV to mid-IR can be characterized.With a homemade compact and alignment-free device,a 5.0 fs pulse at 800 nm corresponding to about two cycles and a 14.3 fs pulse at 1800 nm corresponding to less than three cycles were successfully characterized.  相似文献   

10.
An experimental scheme to realize single-shot spectrometry for the diagnostics of x-ray free-electron lasers (XFELs) is presented. The combination of an ultraprecisely figured mirror and a perfect crystal form a simple, high-precision spectrometer that can cover an energy range from a few eV to a hundred eV with high resolution. The application of the spectrometer to determine XFEL pulse widths was investigated theoretically and experimentally. It has been shown that the present system can determine pulse widths from sub-fs to ps in a single shot even for spontaneous radiation. The system can be easily extended to even shorter pulses.  相似文献   

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