Cavity length dependence of mode beating in passively Q-switched Nd-solid state lasers.

Zameroski, Nathan D.; Wanke, Michael Clement; Bossert, David J

doi:10.2172/1055620

Cited by 1 publication

(2 citation statements)

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“…A candidate original waveform was calculated with the harmonic mode-beating frequency of 800 MHz and modulation depth of 0.5, which is compared with the experimental laser pulse in figure 3(b). An approximate harmonic mode beating frequency is εc/2L C , where c is the speed of light, L C is the cavity length and ε = n/m (n, m: integers) [41,42]. The free spectral range, or fundamental cavity mode, c/2L is about 250 MHz, for the present cavity length in the oscillator section L C = 62 cm, while the experimental mode-beating frequency varies in the range of 500-800 MHz, corresponding to ε = 2-3 for the strongest beat.…”

Section: Resultsmentioning

confidence: 99%

“…Diminishing periods at |z| 1 mm in all the cases result from the reduced breakdown wave speed at the end of the energy coupling. In [42], up to the tenth harmonic of the fundamental cavity mode was observed in the power spectral density of a mode-beating pulse, although there was an external cavity in addition to the master cavity, which contributed to the generation of higher harmonics. If the present single-cavity oscillator output contains up to the eigth harmonic, or f MB = 2.0 GHz, superposed on the lower harmonics, the measured period could be attributed to the frequency component around 2 GHz.…”

Section: Source Of Distributed Elastic Scattering Spotsmentioning

confidence: 99%

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Influence of mode-beating pulse on laser-induced plasma

Nishihara

Freund²,

Glumac

et al. 2018

J. Phys. D: Appl. Phys.

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This paper addresses the influence of mode-beating pulse on laser-induced plasma. The second harmonic of a Nd:YAG laser, operated either with the single mode or multimode, was used for non-resonant optical breakdown, and subsequent plasma development was visualized using a streak imaging system. The single mode lasing leads to a stable breakdown location and smooth envelopment of the plasma boundary, while the multimode lasing, with the dominant mode-beating frequency of 500-800 MHz, leads to fluctuations in the breakdown location, a globally modulated plasma surface, and growth of local microstructures at the plasma boundary. The distribution of the local inhomogeneity was measured from the elastic scattering signals on the streak image. The distance between the local structures agreed with the expected wavelength of hydrodynamic instability development due to the interference between the surface excited wave and transmitted wave. A numerical simulation, however, indicates that the local microstructure could also be directly generated at the peaks of the higher harmonic components if the multimode pulse contains up to the eighth harmonic of the fundamental cavity mode.

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Section: Resultsmentioning

confidence: 99%

Section: Source Of Distributed Elastic Scattering Spotsmentioning

confidence: 99%