Single-mode lasing in diode-pumped passive Q-switch lasers based on neodymium-doped yttrium aluminate and ytterbium-erbium glass active elements

This study considers two types of transversally diode-pumped lasers: a Nd:YAG laser with a Cr4 C VYAG passive Q-switch (lasing wavelength of 1064 nm) and an Yb:Er-glass laser with a Co2C VMgAl2O4 passive Q-switch (1535 nm). The purpose of the study is the experimental and theoretical investigation of the spectral selection properties of the solid-state laser whose monopulses are formed by bleaching filters. Method. The conditions for single-frequency lasing in the laser cavity were defined. Numerical simulations were used to determine the time intervals characterizing the evolution of the monopulses in the laser cavities with the bleaching filters, as well as the number of related radiation trips within the cavities up to the moment of achieving maximum lasing power. Main results. Based on these data, it has been shown that the lasing regime within the cavity of the Yb:Er glass laser with the Co2C VMgAl2O4 passive Q-switch lasts for a longer period compared with that in the Nd:YAG laser with the Cr4C VYAG passive Q-switch. Therefore, the single-mode regime in the Yb:Er-glass laser is realized without introducing an additional frequency-dependent element to the cavity. In contrast, the single-mode regime in the Nd:YAG laser can be achieved by the formation of an interference-polarizing Lyot filter due to thermally induced birefringence of the active element and polarizer. Practical significance. The obtained results have practical applications in the development of compact single-frequency diode-pumped lasers operating within the near-infrared region, including the conditionally safe spectral range. (c) 2024 Optica Publishing Group