Diode-pumped dual-frequency microchip Nd : YAG laser with tunable frequency difference

Abstract

The diode-pumped dual-frequency microchip Nd : YAG laser with tunable frequency difference is presented. The gain medium used is a microchip 2 mm in thickness for miniaturized and integrated design. Two quarter-wave plates are placed into the laser cavity and the intra-cavity birefringence produces two orthogonally linearly polarized modes. The rotation of one of the two quarter-wave plates introduces a controlled and variable cavity birefringence which causes a variable frequency difference between the two orthogonally polarized modes. The frequency difference can be tuned through the whole cavity free spectral range. The obtained frequency difference ranges from 14 MHz to 1.5 GHz. The variation of the beat frequency over a period of 10 min is less than 10 kHz. The lock-in between modes is not found. Experimental results are presented, which match well with the theoretical analysis based on Jones matrices.

Orthogonally polarized dual-wavelength Nd:LuVO_4 laser at 1086 nm and 1089 nm

“…The dual-wavelength lasers with orthogonal polarizations, classifying as the third type, are desirable for the applications of laser interferometry and precision metrology [20,21]. Nd:YAG, Nd:YVO 4 , and Nd:GdVO 4 lasers have been demonstrated recently to achieve the simultaneous emissions of two orthogonally polarized wavelengths, in which an additional birefringent element or second gain medium was employed for obtaining orthogonal linear polarizations [22][23][24]. It will be more practically desirable and convenient to develop a compact orthogonally polarized dual-wavelength laser with a single gain medium in a simple cavity.…”

Orthogonally polarized dual-wavelength Nd:YLiF4 laser

“…The second method uses a polarized beam splitter or a Fabry-Perot etalon with a tilt angle to separate the two wavelength beams with orthogonal polarizations and keep them oscillating in their own cavities. Then the film system of each cavity's output mirror is designed to balance the gain-toloss of the dual wavelengths, so that the thresholds of the dual wavelengths can be equalized [21][22][23][24][25] . By a nonlinear difference-frequency [26] , this kind of small-interval orthogonally polarized dual-wavelength laser beam can realize coherent terahertz (THz) with a frequency range of 0.1-3 Hz.…”

Diode-pumped Pr3+:LiYF4 visible dual-wavelength laser

“…So far, dual-wavelength laser for different transitions of Nd 3 þ have been reported for some crystals such as Nd:YAG [6][7][8][9][10][11][12][13][14][15][16][17][18], Nd:YVO 4 [19][20][21][22][23][24][25][26], Nd:GdVO 4 [27][28][29][30][31], Nd:LuVO 4 [32,33], Nd:YAlO 3 [34][35][36][37] Nd:GSAG [38], Nd:LSO [39], Nd:LYSO [40,41], Nd:SYSO [42] and Nd:YAB [43]. However, few researches on dual-wavelength Nd 3 þ -doped lasers in the visible spectral region have been reported [44][45][46].…”