A novel approach to selective wavelengths emission in mode-locked Nd:YVO₄ lasers via photon emission angles

In this study, we successfully switched the wavelength of a mode-locked pulsed laser output from 1064 nm to 1086 nm by selecting the initial spontaneous emission photons for amplification inside the laser cavity. This was achieved by precisely adjusting the angle of photon propagation within the gain medium (Nd:YVO₄ crystal) and the cavity by introducing a two-pinhole aperture into the cavity. In fact, two setups with identical optical elements and spacing generate two laser beams with different wavelengths were obtained solely by using emitted photons at different angles. In the initial setup, with a pump power of 3.5W, the laser output consisted of pulses with wavelength of 1064 nm, 9nJ energy per pulse and ∼79 MHz repetition rate. In contrast, in the second setup which utilizing identical components to the first configuration, we achieved pulses with wavelength of 1086 nm and 4nJ energy per pulse and similar repetition rate with first one.