Exploiting birefringent thermal lensing effect to manipulate polarization states of an Nd:YVO_4 self-mode-locked laser

Abstract

An Nd:YVO 4 laser with a convex-plano cavity is systematically studied to demonstrate the manipulation of output polarization state by using the birefringent thermal lensing effect of the gain crystal. Based on the theoretical analysis of the cavity stability under the influence of thermal lens, the polarization state of output emission is experimentally confirmed that can be controlled to switch from pure π-to pure σ-polarization by simply varying the pump focus position from the tight-focusing to defocusing conditions. More importantly, it is found that there exists an adequate pump focus position within the switching region to lead the π-and σ-polarization to have balanced gain for achieving a stable selfmode-locked laser with orthogonally polarized components. Under the orthogonally polarized mode-locked operation, the pulse repetition rates are found to be 2.23 and 2.33 GHz for the πand σ-polarization with pulse duration to be 16.1 and 15.1 ps, respectively.

Thermal lensing‐induced soliton molecules in β‐phase gallium oxide

“…From a more general standpoint, birefringence of optical media induced by thermal lensing is a quite common phenomenon in optoelectronic and photonic materials with sizable heat conductivity. This is for instance the case of optoelectronic devices, in which thermally induced birefringence has been shown to enable manipulations of polarization states of solid‐state lasers 38–40 . In the specific context of Nd: self‐mode‐locked lasers, it was experimentally established 38 that thermal lensing effects create an effective refractive index that varies quadrically with the laser focus position along the axis of propagation of the laser.…”

“…This is for instance the case of optoelectronic devices, in which thermally induced birefringence has been shown to enable manipulations of polarization states of solid‐state lasers 38–40 . In the specific context of Nd: self‐mode‐locked lasers, it was experimentally established 38 that thermal lensing effects create an effective refractive index that varies quadrically with the laser focus position along the axis of propagation of the laser. Changes in optical indices of photonic waveguides, due to thermo‐optical effects, have also been reported recently in several experimental as well as theoretical studies 41–45 .…”

Mid-infrared dual-wavelength operation of a diode-pumped Tm:YScO3 laser

“…Coherent THz waves, with a frequency range including frequencies between 100 GHz and 10 THz are promising applications for terahertz communications, detection, imaging systems, and sensing applications [14,15]. For rare-earth doped solid state lasers, the research on the dualwavelength emissions mainly focused on the Nd and Yb doped lasers in the wavelength range from 0.9 to 1.3 µm [16][17][18][19][20][21][22]. However, employing a pump laser in the 2 µm waveband will proportionally increase the quantum efficiency according to the Manley-Rowe relations, which doubles the quantum * Author to whom any correspondence should be addressed.…”

Polarization self-modulation of the coaxial diode-end-pumped orthogonally polarized laser induced by an intracavity waveplate

“…For example, thermal and other characteristic discrepancies between the orthogonal directions of the gain medium can lead to significant variations in longitudinal mode distribution. These variations often exceed the phase locking range, resulting in decoupling of the dual polarizations and unrelated oscillations in orthogonal directions [6,[12][13]. Consequently, the application of this new type of OPL in critical fields such as coherent precision measurement [14][15] becomes challenging.…”