Surface second-harmonic generation in Si(111) for autocorrelation measurements of 248-nm femtosecond pulses

Canto-Said, E. J.; Simon, Péter; Jordan, C.; Marowsky, G.

doi:10.1364/ol.18.002038

Cited by 12 publications

(6 citation statements)

References 15 publications

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“…Unfortunately, however, a 1 m BBO crytal can not be obtained. Another option is surface SHG [15], which has an effective interaction length on the order of a wavelength. Use of extremely short interaction lengths of materials can phase match the broadband SC, but it seriously decreases the sensitivity.…”

Section: Experimental Geometrymentioning

confidence: 99%

Toward single-shot measurement of a broadband ultrafast continuum

2008

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We discuss the problem of measuring the intensity and phase of a broadband continuum in a single shot, considering three possible methods, and perform preliminary measurements using one of them. Our measurements use transient-grating cross-correlation frequency-resolved optical gating (TG XFROG) with a thirdorder nonlinear medium, which currently can phase match over 300 nm simultaneously. We demonstrate this technique for a continuum generated in bulk fused silica that is 12.5 mm thick. Due to limited reference-pulse energy, we do not achieve a true single-shot measurement, instead averaging over approximately five shots. The retrieved trace and spectrum contain fine structure, and the retrieved temporal phase is mainly quadratic.

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Section: Experimental Geometrymentioning

confidence: 99%

Toward single-shot measurement of a broadband ultrafast continuum

2008

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“…Autocorrelators based on the second and third harmonic signal from metal surfaces have been realized with near-IR ultrafast pulses [13,20,21]. UV pulses of 248 nm have been autocorrelated using surface SHG from silicon [11]. Second harmonic has also been generated from interfaces such as Si/ SiO 2 [22].…”

Section: Surface Second-harmonic Generationmentioning

confidence: 99%

“…The twophoton absorption method provides a broader response [10] than nonlinear crystals but is still somewhat limited in that the bandgap of the material must be bigger than one-photon energy but smaller than the energy of two photons ͑ប Ͻ E gap Ͻ 2ប͒. Recently, surface harmonic generation from metallic surfaces has gained interest in the ultrafast community, because it is inexpensive and simple to align, and has an extremely broad upconversion bandwidth [11][12][13]. It is also possible to perform secondharmonic generation (SHG) and third-harmonic generation (THG) from dielectric mirrors, where THG often dominates SHG [14].…”

Section: Introductionmentioning

confidence: 99%

Gold-SPIDER: spectral phase interferometry for direct electric field reconstruction utilizing sum-frequency generation from a gold surface

Anderson

Witting

2008

J. Opt. Soc. Am. B

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We report on a version of spectral phase interferometry for direct electric field reconstruction (SPIDER) that uses no nonlinear crystals, instead relying on the harmonic signal from a gold mirror. Surface harmonic generation holds the promise of being able to upconvert extremely broad bandwidths over a large tuning range, thus providing access to both extremely short pulses and wavelengths outside of traditional methods. In this proof of principle demonstration, SPIDER traces for chirped and transform-limited 55 fs pulses are presented.

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“…BBO begins to absorb heavily at 190nm. Surface SHG [19] is an option because its effective interaction length is less than a wavelength (so phase-matching is irrelevant), and the signal does not propagate through the crystal. However, if the fundamental wavelength of the pulse to be measured is below "-'380 nm, the SH signal is in the vacuum UV, where it's absorbed by oxygen.…”

Section: Pushing Shg To Its Limitsmentioning

confidence: 99%

“…Measuring the weaker pulse's spectrum vs. delay yields the pulse intensity and phase. The algorithm requires solving the nonlinear Shrodinger equation for propagation through the non-linear medium (see Chapters [18][19][20] for analogous problems), but it works.…”

Section: High-power Frogmentioning

confidence: 99%

Ultraviolet and High-Power Pulse Measurement

Backus¹,

Durfee²

2000

Frequency-Resolved Optical Gating: The Measurement of Ultrashort Laser Pulses

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The Issues in UV and High-power Pulse MeasurementSo far, we've discussed the general ideas behind FROG and an array of tricks for simplifying FROG measurements. And because nearly every ultrafast lab's workhorse laser is an infrared low-power Ti : Sapphire oscillator, our discussion revolved around SHG FROG, which is ideal for measuring such pulses. Consequently, in this chapter, we consider quite different problems: the measurement of ultraviolet and high-power pulses. These are interesting-and important-problems that are often neglected in discussions of measurement techniques.Indeed, many researchers believe it's not possible to measure UV pulses because SHG crystals don't exist in this wavelength range. While such crystals don't, in fact, currently exist, third-order FROG methods work beautifully in the UV, where third-order nonlinearities yield signal pulses at the same wavelength as the input pulse. Also, third-order nonlinearities are stronger in the UV, so even relatively weak pulses are measurable.On the other hand, many researchers believe that high-power pulse measurement is trivial; after all, there's plenty of intensity-which means that any nonlinearity will yield plenty of signal-so what's the problem? The problem is that high-power pulses have their own unique problems that seriously complicate their measurement. For a variety of reasons, not the least of which is the high complexity of amplifier systems that produce them, they tend to have poor spatial quality. Worse, they suffer from spatio-temporal distortions, such as spatial chirp, in which the intensity and phase vary from point to point across the beam. Such distortions violate the assumption made by essentially all pulse measurement techniques that the intensity and phase vs. time are the same throughout the beam. We'll discuss measuring the intensity and phase vs. time and space later, but for now, we'll see that FROG's ability to check the accuracy of a measurement will be crucial for such measurements. And to further complicate the problem of measuring high-power pulses, their temporal distortions can also be quite severe. And at the same time, our standards for them can be higher. For example, they can have satellite pulses several orders of magnitude less intense. Weaker satellites would be of no significance in low-power pulses, but, in high-power pulses, they can be intense enough to do some damage, so we really need to know about them. Finally, high-power pulses also tend to have significant fluctuations from shot to shot, necessitating single-shot methods. Interestingly, third-order FROG methods R. Trebino, Frequency-Resolved Optical Gating: The Measurement of Ultrashort Laser Pulses

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Surface second-harmonic generation in Si(111) for autocorrelation measurements of 248-nm femtosecond pulses

Cited by 12 publications

References 15 publications

Toward single-shot measurement of a broadband ultrafast continuum

Toward single-shot measurement of a broadband ultrafast continuum

Gold-SPIDER: spectral phase interferometry for direct electric field reconstruction utilizing sum-frequency generation from a gold surface

Ultraviolet and High-Power Pulse Measurement

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