T-shaped cavity dual-frequency Nd:YAG laser with electro-optical modulation

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

“…In 2016, our group also reported a TCDFL with electro-optical modulators [ 37 ], as shown in Figure 31 , which consisted of two standing-wave cavities that shared the same gain medium of Nd:YAG. An electro-optic birefringent filter consisting of PBS and lithium niobate (LN) was used not only to select longitudinal mode but also to tune frequency and frequency difference.…”

“… Schematic of two-cavity dual-frequency Nd:YAG laser [ 37 ]. FCLD: fiber-coupled laser diode; GL: gradient-index lens; PBS: polarizing bean splitter; LN: lithium niobate; HVS: high-voltage source; OC: output coupler.…”

“… Oscillating spectrum of dual-frequency laser with different frequency differences of ( a ) 0 GHz and ( b ) 132 GHz [ 37 ]. …”

“…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 ].…”