The generation of near-and mid-infrared vortex mode is demonstrated from a 1 µm nanosecond optical vortex pumped optical parametric oscillator using a multi-grating MgO-doped periodically poled lithium niobate crystal with five grating domains. This system enables the orbital angular momentum between the signal and idler outputs to be exchanged simply by controlling the cavity Q-factor, and a vortex output in the wavelength ranges of 1.36-1.63 µm or 3.07-4.81 µm could be obtained. A maximum signal (idler) vortex output energy of 4.3 mJ (2.2 mJ) was achieved at a pump energy of 21 mJ, which corresponds to an optical-optical conversion efficiency of over 20% (10%).

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We investigated high energy, near and mid-infrared optical vortex lasers formed by a 1 μm optical vortex-pumped KTiOAsO4 (KTA) optical parametric oscillator. The orbital angular momentum (OAM) of the pump beam can be selectively transferred to the signal or idler output by changing the reflectivity of the output coupler. With this system, 1.535 µm vortex signal output with an energy of 2.04 mJ and 3.468 µm vortex idler output with an energy of 1.75 mJ were obtained with a maximum pump energy of 21 mJ, corresponding to slope efficiencies of 14% and 10%, respectively. The spectral bandwidth (full width at half maximum, FWHM) of the signal and idler vortex outputs were measured to be Δλs ~ 1.3 nm (~ 5.5 cm−1) and Δλi ~ 1.7 nm (~ 1.4 cm−1), respectively.

We generate a tunable (2.3–3 μm) optical vortex output with an order of 1 or 2 from a 1 μm 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 mid-infrared idler output in this signal singly resonant high-Q cavity configuration. A maximum vortex output energy of 1.52 mJ was achieved within a wavelength tuning range of 2.27–2.96 µm. The signal beam with the Gaussian spatial profile was also generated within a 1.66–2 μm tuning range. The wide spectral bandwidth was experimentally measured near the wavelength degeneracy and explained by theoretically.

Abstract:We pursue unique direct writing approaches with femtosecond fiber laser and relevant photonic manufacturing in developing various micro-nano-devices for microelectronics, energy and sensing applications. In this paper, we will present our research progresses on four directions: direct writing of microball lenses for super-wide angle imaging, developing innovative Au/reduce graphene oxide(Au/rGO) super-capacitors with high rates and fast response, multilayer supercapacitors directly written on polyimide and interdigitated capacitance sensors.