Instability Risk and Beam Profile Variation in Optical Ring Resonator due to Thin Gradient Index Lens

In this study, a simple ring resonator model in presence of thin gradient index (GRIN) lens is investigated to characterize the optical beam maginification quality beyond its traditional modalities. This model allow us to vary and control the limit of resonator stability more significantly.It consist of two folding arms and each arm can be realized by its cavity components. Insertation of thin GRIN lens ( thickness < 9.3mm) in ring resonator, mainly in between first folding range gives the magnified output beams and meets the beam expander feature for the laser. Variation of GRIN lens thickness (L) is an emphatic and influencing parameter than its refractive index (n) to disturb the resonator stability. Resonator stability in Tangential (T) plane is relatively more sensitive than sagittal (S) plane. Vigorous magnification in optical beam size at the end of output range in a cavity is the noticeable consequences because of GRIN lens.