Design and Experimental Study of Tunable Dual-Frequency Nd∶YAG Laser with Large Frequency Difference

Advances of Research on Dual-Frequency Solid-State Lasers for Synthetic-Wave Absolute-Distance Interferometry

“…In order to obtain a tunable dual-frequency laser with a large frequency difference, our group designed and investigated a diode-pumped dual-frequency Nd:YAG laser with a tunable frequency difference [ 35 ], as shown in Figure 25 , using the light-splitting and polarizing functions of the PBS to form perpendicular linear and right-angle standing-wave cavities. Both cavities included a birefringent output coupler (BOC) fabricated from calcite crystal, and they employed a birefringent filter of PBS-BOC acting as laser-longitudinal-mode selectors.…”

“… Schematic diagram of dual-frequency Nd:YAG laser system at 1064 nm [ 35 ]. LD: laser diode; GL: gradient-index lens; PBS: polarizing beam splitter; BOC: birefringent output coupler; M: mirror.…”

“… Oscillating spectra of dual-frequency laser with different frequency differences of ( a ) 11.9 GHz and ( b ) 148.4 GHz [ 35 ]. …”

“…Many experts and scholars worldwide have investigated the oscillating principles and key technologies of dual-frequency solid-state lasers with tunable and large frequency difference since 2000 [ 14 , 15 , 16 , 17 , 18 , 19 ], and they have successfully developed a series of new dual-frequency solid-state lasers, such as the birefringent dual-frequency solid-state laser [ 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 ], the biaxial dual-frequency solid-state laser [ 31 , 32 ], the two-cavity dual-frequency Nd:YAG laser (TCDFL) [ 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 ], and so on. Especially in the recent years, our research group has made important progresses in the research and development of the TCDFL and its quadrature-demodulated Pound–Drever–Hall (QD-PDH) frequency-stabilizing technology [ 41 , 42 ], and the QD-PDH frequency-stabilizing method has been applied to the frequency-difference stabilization of the TCDFL with a frequency difference of 24 GHz at 1064 nm [ 43 , 44 ].…”