Exploiting the Etalon Effect to Manipulate the Pulse Characteristics of the Self-Mode-Locked Nd:Yvo4 Laser with Flexible Cavity Length

Abstract

By exploiting the etalon effect for mode selection, the pulse characteristics of the self-mode-locked (SML) laser are investigated. Employing different simulation parameters, the various longitudinal-mode oscillation states and the corresponding optical spectra are theoretically analyzed firstly. In the experiments, by increasing the ratio of the etalon thickness to the laser cavity length and tuning the laser crystal heat sink temperature, the SML laser experienced in adjacent longitudinal-mode, multi-group longitudinal-mode, and spaced longitudinal-mode oscillation states successively. The experimental results show when the laser cavity length increases from 55 to 95 mm and the etalon thickness increases from 4 to 41 mm, the output power decreases from 801.32 to 603.63 mW with the pump power at 6.51 W. The number of locked modes in the SML laser first increases from six to nine and then decreases to four, corresponding to the SML pulse repetition frequency first increases from 2.70 GHz to 4.00 GHz and then decreases to 1.58 GHz. The experimental results are in good agreement with the theoretical analysis.

Keywords: self-mode-locked laser, etalon effect, longitudinal-mode oscillation state.