Abstract

Subject of study. This study considers two types of transversally diode-pumped lasers: a Nd:YAG laser with a Cr⁴⁺:YAG passive Q-switch (lasing wavelength of 1064 nm) and an Yb:Er-glass laser with a Co²⁺:MgAl₂O₄ 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 Co²⁺:MgAl₂O₄ passive Q-switch lasts for a longer period compared with that in the Nd:YAG laser with the Cr⁴⁺:YAG 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.

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