tailieunhanh - Acoustic Waves From Microdevices to Helioseismology Part 11

Tham khảo tài liệu 'acoustic waves from microdevices to helioseismology part 11', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 388 Acoustic Waves - From Microdevices to Helioseismology instant photograph of the spatial arrangement of such a structure. The photons with the wavelength resonant with the structure Xg ng mA will occupy different spatial positions in the photograph with respect to the layers of thickness linv Ằg ng. And only a small part of the total number of photons in the resonator of our DFB laser will coincide in position and phase with the inversion maxima in the medium and therefore will be amplified efficiently during the lifetime tinv T of the layers of the given spatial configuration forming a beam on the basis of photon trains. During the movement of the inversion layers structure following the movement of the hypersonic wave new groups of phased photons will be formed and their frequency will shift with changing the structure parameters. In such a way the model considered above explains the appearance of the sharp angular radiation pattern of the broadband lasing of ytterbium in the crystal and glass. In the case of a thick sinusoidal grating photons occupying different positions in space which is equivalent to the large phase dispersion within the photon train are amplified. This leads to the increase in the radiation divergence. Thus when a periodic spatial grating of thin inversion layers is produced in the active medium the high-directional stimulated radiation of an ensemble of excited atoms can be observed in the optical range. 6. Features of ytterbium lasing line spectra data interpretation Line spectra observed in the crystal and glass relate to the second stage of Yb-lasing. The second stage is the Yb-lasing in the resonator after the end of pump due to inversion remained in the medium. Of special interest the details of Yb spectra are. Twisted inclined and structured lines in spectra were observed in the region pm 16. Figures 11 13 14 showed an inclination of some lines to the short-wavelength side of the spectrum in respect to the .