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Design And Application Of Utralshort Pulse Dispersion Compensation Mirrors

Posted on:2015-04-14Degree:MasterType:Thesis
Country:ChinaCandidate:G YangFull Text:PDF
GTID:2180330422491686Subject:Optics
Abstract/Summary:PDF Full Text Request
In the laser system of utralshort pulse, the technique of dispersion compensation isalways very important. With the development of utralshort pulse technology, it becomesdifficult for traditional compensating element of dispersion to function ideally in theprocess of compensating for the dispersion of utralshort pulse nowadays. However, thisquestion is eased by the appearance of the concept of chirped mirror. With hugeadvantages, the chirped mirror outweighs the traditional compensating element in that,since it is not sensitive to the light path, the bandwidth of compensating dispersion iswide enough to compensate the higher-order dispersion and compensate the dispersionvery accurately. The chirped mirror has been a hot research area since it is presented.China is late in this field, and the achievement in designing and applying the chirpedmirror is insufficient. Thus, this thesis focuses on the design and application of thechirped mirror.Then we reviews the characteristic equation of optical transmission in themultilayer based on Maxwell equation, and computes the reflection phase of multilayerby using this characteristic equation. This is followed by the discussion of thecouple-mode theory of chirped mirror. Hereafter we discusses methods of designing thechirped mirror, and designs a chirped mirror, with a central wavelength of800nm, aneffective bandwidth of750nm-850nm, and the dispersion compensation of-60fs2.Furthermore, a matched pair design is carried out to reduce the oscillating amplitude ofdispersion from20fs2to5fs2, which effectively restrains the oscillation ofdispersion curve.On the basis of before we bring in the evaluation function of chirped mirror, andintroduces an optimized algorithm, the Memetic, by which the ultra wideband chirpedmirror is developed, with a central wavelength of825nm, an effective bandwidth of600nm-1100nm, and the dispersion compensation of-100fs2. A matched pair design isalso carried out to reduce the oscillating amplitude of dispersion from200fs2to50fs2. Then, this chirped mirror is produced. By analyzing the dispersion curve of thisproduct, then we try to figure out the reasons that generate the error.In the experimental part we introduce two ways of measuring the utralshort pulse,the autocorrelation method and FROG method. Then, the10.3fs utralshort pulse is madeto pass through a BK7crystal that is1mm thick and a LBO crystal that is0.5mm thickrespectively. The dispersion from these two situations is compensated by the designedchirped mirror in this study and is measured by FROG method. The final discoveryshows that two complete dispersion compensations could help to restore the pulse to itsinitial state, even better than its initial state. Besides, the excess negative dispersioncould widen the pulse once again. This demonstrates that the designed chirped mirror in this study could be fully applied to dispersion compensation of the pulse.
Keywords/Search Tags:ultrashort pulse, dispersion compensation, chirped mirror
PDF Full Text Request
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