A multicrystal harmonic generator that compensates for thermally induced phase mismatch

Wu, Sheng; Blake, Geoffrey A.; Sun, Han; Ling, John

doi:10.1016/s0030-4018(99)00580-5

Cited by 12 publications

(8 citation statements)

References 6 publications

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“…The effects of high pulse energy are visible even at 10-Hz repetition rates, where saturation and a slight decrease in conversion efficiency are observed at the highest input intensities. These effects, typically attributed to transient absorption [13] and thermal phase mismatch [14], are even more significant for burst-mode operation because of the nearly 1009 higher energy imposed within the 10-ms burst duration as compared to a single 10-Hz pulse. The bars represent a standard 5 % uncertainty determined from 100 laser bursts.…”

Section: Burst-mode Fourth-harmonic Generationmentioning

confidence: 99%

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Simultaneous high-speed planar imaging of mixture fraction and velocity using a burst-mode laser

et al. 2013

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Simultaneous high-speed quantitative imaging of mixture fraction and velocity is demonstrated using the fourth-and second-harmonic outputs, respectively, of a burst-mode Nd:YAG laser. A tenfold increase in the record length and 16-fold increase in per-pulse energy are achieved compared with previous measurements of mixture fraction using burst-mode and continuously pulsed diode-pumped solid-state lasers, respectively. The high output energy is used for quantitative, high-speed mixture-fraction imaging with acetone planar laser-induced fluorescence, which also enables simultaneous particle-based velocimetry without interference from particle scattering. A semiquantitative model is used to determine the limitations on fourth-harmonic output energy due to the effects of transient absorption and thermal phase mismatch over a range of repetition rates. Data are presented for mixing within a turbulent jet (Reynolds number of 15,000) and are validated by comparisons with known turbulent mixing laws and previously published data.

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Section: Burst-mode Fourth-harmonic Generationmentioning

confidence: 99%

“…1. Instead, the absorption of E 4 causes thermal heating of the crystal, driving a nonlinear reduction in conversion through thermal phase mismatch [13,14]. At high repetition rates, transient absorption is the primary mode for depositing heat in the crystal.…”

Section: Burst-mode Fourth-harmonic Generationmentioning

confidence: 99%

Simultaneous high-speed planar imaging of mixture fraction and velocity using a burst-mode laser

et al. 2013

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“…The conversion efficiency increases at first, but then flattens out as the interaction length increases. [42][43][44] For this reason, the TP and QP configurations are not certainly superior to the DP one. Also, the theoretical estimation of the influence of thermal dephasing on the efficiency in KBBF needs the thermal conductivity and correct absorption coefficient of the crystals.…”

Section: Thermal Dephasingmentioning

confidence: 99%

“…The temperature variations of refractive indexes of KBBF are also needed to calculate the SHG temperature bandwidth. [44][45][46] But these data are not available to date.…”

Section: Thermal Dephasingmentioning

confidence: 99%

Numerical Study of Multiple-Pass Effect by Total Internal Reflection on Second-harmonic Conversion in KBe₂BO₃F₂Crystal

Chang¹,

Wang²

2004

Jpn. J. Appl. Phys.

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We apply total internal reflection to significantly extend the effective length of KBe 2 BO 3 F 2 crystal. Thus the conversion efficiency for second-harmonic generation can be increased in principle. However, the total reflection also leads to an adverse effect on the conversion efficiency. Three multiple-pass configurations to extend the effective interaction length of the crystal are proposed and discussed in this paper. Numerical analysis shows that the double-pass configuration is more favorable for second-harmonic generation to below 200 nm. At the medium input intensity of 200 MW/cm 2 , the configuration gives a conversion of 27.1% at the second-harmonic wavelength of 193 nm. A conversion of 45.2% is obtained as the input intensity is increased to a higher value of 500 MW/cm 2 .

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“…Eimerl [8] and Wu et al [9] reported that the N-Plate crystal configuration can compensate for the thermally induced phase mismatch, effectively increasing the interaction length of nonlinear optical crystals during harmonic generation under high loading. Yao et al [10] developed an external cooling method, gas cooling at the exit face of the crystal, which initiated a negative temperature profile that compensated for the positive profile RESEARCH ARTICLE Translated from Chinese Journal of Quantum Electronics,2005,22 (4) (in Chinese) generated from laser absorption.…”

Section: Introductionmentioning

confidence: 99%

The thermal effect analysis in the high power frequency-doubled Nd:YAG Laser

Yao

Wang

2006

Front. Phys. China

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In the high power frequency-doubled Nd:YAG Laser, the temperature inside a nonlinear crystal will become non-uniform due to the absorbtion of the fundamental and second harmonic waves, leading to phase mismatch, conversion efficiency reduction and output power instability. This phenomenon appears severe in the high-power high-repetition rate laser system. In this paper, temperature distribution inside a KTP crystal was analyzed by solving the thermal conductivity equation. According to the temperature distribution of the KTP, we have theoretically calculated the optimal phase matching angles, tolerance angles and walk-off angles of type II KTP crystal as a function of temperature.

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A multicrystal harmonic generator that compensates for thermally induced phase mismatch

Cited by 12 publications

References 6 publications

Simultaneous high-speed planar imaging of mixture fraction and velocity using a burst-mode laser

Simultaneous high-speed planar imaging of mixture fraction and velocity using a burst-mode laser

Numerical Study of Multiple-Pass Effect by Total Internal Reflection on Second-harmonic Conversion in KBe₂BO₃F₂Crystal

The thermal effect analysis in the high power frequency-doubled Nd:YAG Laser

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A multicrystal harmonic generator that compensates for thermally induced phase mismatch

Cited by 12 publications

References 6 publications

Simultaneous high-speed planar imaging of mixture fraction and velocity using a burst-mode laser

Simultaneous high-speed planar imaging of mixture fraction and velocity using a burst-mode laser

Numerical Study of Multiple-Pass Effect by Total Internal Reflection on Second-harmonic Conversion in KBe2BO3F2Crystal

The thermal effect analysis in the high power frequency-doubled Nd:YAG Laser

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Numerical Study of Multiple-Pass Effect by Total Internal Reflection on Second-harmonic Conversion in KBe₂BO₃F₂Crystal