Characterization of femtosecond pulses via transverse second-harmonic generation in random nonlinear media

Trull, J.; Saltiel, S.; Roppo, Vito; Cojocaru, C.; Dumay, David; Królikowski, Wiesław; Neshev, Dragomir N.; Vilaseca, R.; Staliūnas, Kęstutis; Kivshar, Yuri S.

doi:10.1007/s00340-009-3449-4

Cited by 20 publications

(28 citation statements)

References 32 publications

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“…From these measurements, summarised in table 1, we can observe that the pulse duration at the maximum compression point is of the order of 30fs in all cases. Notice that the value of τ o could be also obtained by measuring the pulse duration directly at the entrance of the crystal but, since the temporal broadening of such short pulses along the 10 mm path is quite large, an accurate measurement of the pulse duration at this point would require the use beams broader enough to provide complete overlap along the crystal length [11]. However, with our proposed method this condition can be relaxed since overlapping of the pulses is required just close to the maximum compression position.…”

Section: (T)=e O (T)exp(-iω O T) With: (3)mentioning

confidence: 99%

“…The implementation of a single-shot autocorrelation (AC) technique based on the recording of the TSHG due to non collinear interaction of two replicas of the unknown pulse intersecting inside a nonlinear random crystal of SBN crystal has been recently demonstrated for pulses in the 200 fs range [11] from a Ti:saphire oscillator with 5 nJ/pulse at 76 MHZ repetition rate. In contrast to the traditional single shot AC setup [12] where the SH trace is recorded in the forward direction at the output of the nonlinear crystal, the TSHG captures the SH trace emitted in a lateral direction, at 90º with respect to the propagation direction of the input beams, and it allows for single-shot measurement of the AC trace as a function of the propagation distance inside the crystal.…”

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confidence: 99%

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Ultrashort pulse chirp measurement via transverse second-harmonic generation in strontium barium niobate crystal

Trull

Sola

Wang

et al. 2015

Applied Physics Letters

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Pulse compression in dispersive Strontium Barium Niobate (SBN) crystal with a random size and distribution of the antiparallel orientated nonlinear domains is observed via transverse second harmonic generation. The dependence of the transverse width of the second harmonic trace along the propagation direction allows for the determination of the initial chirp and duration of pulses in the femtosecond regime. This technique permits a real-time analysis of the pulse evolution and facilitates fast in-situ correction of pulse chirp acquired in the propagation through an optical system. Ultrashort laser pulses, with their variety of peak powers and durations, are becoming an important tool in an increasing number of applications in the fields of technology (materials processing, etc.) biomedical sciences and basic research in general. As the pulses become shorter, the dispersion effects that modify pulse properties during propagation through optical materials become increasingly relevant so a precise characterization of the pulse properties is needed. During the last decade different techniques have been implemented and extensively adopted [1][2][3][4] either for partial or/and complete temporal characterization of the pulses. They include for instance, Frequency-Resolved Optical Gating (based on the concept of optical gating) or Spectral Phase Interferometry for Direct Electric-field Reconstruction, (based on the concept of spectral interferometry) or even for 3D characterization (STARFISH, SEA Tadpole) [5][6]. Although a detailed field reconstruction is needed in particular applications and thus fully justifies the use of these advanced techniques, there are still many situations requiring just a partial characterization of the pulse. Hence simple and cost-effective methods of pulse measurement and characterization are always of potential interest.Typical as-grown ferroelectric crystals, such as Strontium Barium Niobate (SBN), exhibit a random-sized distribution of needele-like oppositely oriented ferroelectric domains all aligned parallel to the optical axis (z axis). A shematic representation of such domains is shown in Figure 1a. While the reversed orientation of domains corresponds to inversion of sign of the quadratic susceptibility, the refractive index of these crystals remains practically homogeneous [7]. Such crystals provide phase matching for frequency conversion processes over wide angular and frequency bandwidths without need for angular or temperature tuning as it is usual in typically used homogeneous nonlinear crystals [8][9][10]. Phase matching is obtained thanks to the continuous set of reciprocal lattice vectors, G, arising from the random size and distribution of the nonlinear domains, which entails a random distribution of the nonlinearity sign. These lattice vectors, with different modulus and orientation, lie in the xy plane. As a result, planar second harmonic emission is observed when the input fundamental beam propagates in the direction perpendicular to the optical axis. This effect consti...

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Section: (T)=e O (T)exp(-iω O T) With: (3)mentioning

confidence: 99%

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confidence: 99%

Ultrashort pulse chirp measurement via transverse second-harmonic generation in strontium barium niobate crystal

Trull

Sola

Wang

et al. 2015

Applied Physics Letters

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“…Therefore, disclosing the nature of the switching mechanism in external electric field remains of particular scientific and technological interest [2,3]. The main features of relaxors include a very broad and frequencydependent dielectric anomaly with the high dielectric permittivity values [4].…”

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confidence: 99%

Effect of Ni doping on ferroelectric and dielectric properties of strontium barium niobate crystals

et al. 2011

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The influence of Ni doping on the ferroelectric and dielectric properties have been examined in Sr 0.61 Ba 0.39 Nb 2 O 6 (SBN:61) relaxor crystals. The dopants introduced into SBN:61 crystals promote the switching process by reducing the value of threshold nucleation field, and thus coercive field. We present real-time studies of domain nucleation and growth processes in doped SBN:61 by the nematic liquid crystal (NLC) decoration technique. The broad phase transition and low-frequency dielectric dispersion that are exhibited by doped SBN:61 samples have a strong link to the configuration of the ferroelectrics microdomains, which in turn is strongly determined by Ni ions concentration.

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“…The non-collinear interaction is preferable for autoand crosscorrelation measurements of femtosecond pulses because of the background free auto-and crosscorrelation traces [5][6][7][8][9][10]. Recently disordered nonlinear media were successfully used for these purposes [11][12][13][14]. Despite the numerous studies on non-collinear SHG [5,11,15], the theory though lacks consistency.…”

Section: Introductionmentioning

confidence: 99%

“…Recently disordered nonlinear media were successfully used for these purposes [11][12][13][14]. Despite the numerous studies on non-collinear SHG [5,11,15], the theory though lacks consistency.…”

Section: Introductionmentioning

confidence: 99%

Theory of noncollinear frequency doubling of transform limited pulses in non-steady-state regime

2016

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We consider non-collinear second harmonic generation from two ultrashort pulses intersecting in a nonlinear medium in spectral and time domains. We derive analytical expressions for the second harmonic amplitude in crystals of finite thickness and obtain a refined phase-matching condition. The contribution from characteristics of the fundamental radiation and interaction geometry to the process is analyzed. We find that the spectral bandwidth is determined by the intersection angle and can be enlarged. The SH pulse duration can be optimized by varying the fundamental beam size and the intersection angle. It is shown that the fundamental pulse duration can be readily characterized with single pulses by means of measuring the second harmonic beam profile. The approach developed can potentially be used to calculate parametric interactions in one-and two-dimensional nonlinear photonic crystals.

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Characterization of femtosecond pulses via transverse second-harmonic generation in random nonlinear media

Cited by 20 publications

References 32 publications

Ultrashort pulse chirp measurement via transverse second-harmonic generation in strontium barium niobate crystal

Ultrashort pulse chirp measurement via transverse second-harmonic generation in strontium barium niobate crystal

Effect of Ni doping on ferroelectric and dielectric properties of strontium barium niobate crystals

Theory of noncollinear frequency doubling of transform limited pulses in non-steady-state regime

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