The Output Characteristics Of Near-infrared 1.3-3 ?m Optical Vortex Parametric Oscillator Based On MgO:PPL

Near-infrared lasers in the wavelength range of 1-3?m are of interest in many fields,particularly,near infrared 1.3-3?m vortex laser sources are useful in many applications due to its unique optical properties.Optical parametric oscillator(OPO)technology is an effective way to achieve the near-infrared continuous tunable lasers.Wide range of wavelength tunability and large non-linear coefficient of the Quasi-phase matching crystals widely used in non-linear frequency conversion.In this research,investigated a quasi-phase-matched Mg O-doped periodically poled lithium niobate(Mg O:PPLN)linear cavity single-resonant optical parametric oscillator.Wavelength tunabilty of the system achieve by controlling the temperature and period of the crystal.The main content of this article is:(1)We demonstrated a single-resonant optical parametric oscillator(OPO)formed of a Mg O-doped periodically poled Li Nb O₃(Mg O:PPLN)crystal pumped with a 1.064?m nanosecond laser.When the periodic polarization period of the Mg O:PPLN crystal is 31?m,the wavelength tuning range of the signal is 1.661-2.057?m and the idler wavelength tuning range is 2.247-2.958?m through temperature tuning.When the pump energy is 20 m J,the highest energy is 1.786 m J of signal and 1.814 m J of idler output,corresponding to a total conversion efficiency of 18%.(2)We generated a tuneable(2.3–3?m)optical vortex output with an order of 1or 2 from a 1?m optical-vortex-pumped singly resonant parametric oscillator based on a Mg doped periodically poled lithium niobate crystal.The orbital angular momentum(OAM)from the pump vortex beam was transferred to the idler output in this signal singly resonant high-Q cavity configuration.A maximum vortex output energy of 1.52m J was achieved across a wavelength tuning range of 2.27–2.96?m.The signal beam in the Gaussian intensity distribution was also imaged across a 1.66–2?m tuning range.The wide spectral bandwidth was experimentally measured near the wavelength degeneracy and theoretically explained by group velocity mismatch and group velocity dispersion.