Effects of spatial hole burning in 888 nm pumped, passively mode-locked high-power Nd:YVO4 lasers

Manipulating the longitudinal mode distribution in the self-mode-locked Nd:YVO4 laser with flexible reflectivity and tilted mirror

“…Author Specific method for manipulating longitudinal mode distributions Schfer et al 12 Tuning the length of the gain medium Jin et al 13 Tuning the pump power Tuan et al 11 Adjusting the cavity length Chen et al 14 Forming an intracavity etalon with gain medium, and controlling the ratio of the etalon thickness to the cavity length by moving the cavity mirrors Sung et al 15 Forming an intracavity etalon with the pump facet of the laser gain medium and the front mirror, and adjusting the laser cavity length to a commensurate ratio of the etalon thickness to the cavity length Our method Forming an intracavity etalon with the pump facet of the laser gain medium and the front mirror, and adjusting the reflectivity and tilt angle of the output mirror of the laser cavity…”

“…When the gain medium length was 4 mm, the SML laser pulse train formed by four longitudinal modes with an average output power of 11.1 W and a pulse width of 9.5 ps was achieved. 12 Jin et al controlled the longitudinal modes by tuning the pump power and found that the higher pump power was beneficial for more longitudinal mode oscillation. When the pump power was 6788 mW, a 1.56-GHz high-repetition laser pulse formed by four longitudinal modes with an average output power of 1605 mW was achieved in the Nd∶YVO 4 laser.…”

“…15 In addition, Schäfer and Yuan mentioned that the output mirror reflectivity affected the SML pulse characteristics such as pulse width. 12,16 Table 1 is organized to express the differences of these methods more intuitively.…”

Effect of spatial hole burning on a dual-wavelength mode-locked laser based on compactly combined dual gain media

“…The relatively compact structure of the current setup enables us to readily investigate the influence of the SHB effect on the mode-locked performance of our dual-wavelength laser. For a standing-wave cavity, it is well known that the amount of the SHB effect could be controlled by varying the separation between the input end mirror and the gain medium [23][24][25][26]. Thanks to the enhancement of the SHB effect, the pulse width for the case of gain-at-the-end (GE) scheme is found to be shorter than that of gain-in-the-middle (GM) architecture under the same cavity configuration.…”

“…As a consequence, the optical conversion efficiency can be significantly improved to be higher than 20% as compared with our previous work. Since the effect of spatial hole burning (SHB) in the gain medium has been recognized to play an important role in mode-locked solid-state lasers [23][24][25][26], we further systematically explore the influence of the SHB effect on the mode-locked performance of our dual-wavelength laser. By decreasing the separation between the input end mirror and the gain medium, it is found that not only the pulse duration will continuously decrease thanks to the enhanced SHB effect, but also that the temporal behavior gradually displays a narrow-peak-on-a-pedestal shape for the Nd:YVO 4 ∕ NdLuVO 4 scheme and a multipulse shape for the Nd:YVO 4 ∕ Nd:KGW configuration.…”