Amplitude and phase modulation of optical feedback in a-cut Nd:YVO₄ laser with a birefringent external cavity

Abstract

Considering only the self-mixing interference taking place, the modulation effect of optical feedback in a single polarization a-cut Nd:YVO4 laser is presented. The output intensity of the laser with anisotropic gain medium is modulated with a wave plate (WP) in the external cavity. The rotation orientation and phase retardation of the WP regularly determinate the amplitude and phase of laser intensity fringe, because the feedback light component at the same polarization direction as the output laser can interact with the light field in the cavity. The corresponding theoretical model is established and the windowed Fourier transform method is utilized to quantitatively explain this phenomenon. By introducing the amplitude and phase modulation coefficients, comparisons of experimental results with simulation analysis show good consistency.

Red and green dual-wavelength Pr:LiGdF4 laser with a single birefringent filter

“…Continuous-wave (CW) dual-wavelength lasers, which emit in the infrared spectral region with wavelengths separated by a few THz, have been established and applied in THz imaging and spectroscopy [1][2][3][4][5]. At present, CW dual-wavelength lasers for different transitions of Nd 3+ or Yb 3+ have been reported for some crystals [6][7][8][9][10][11][12][13][14][15][16]. However, few researches on dual-wavelength Nd 3+ -doped lasers in the visible spectral region have been reported [17][18][19].…”