A passively Q-switched Nd:YAG/Cr⁴⁺:YAG microchip laser operating at 1112 nm is demonstrated. Under a pump power of 5.5 W, a maximum average output power of 623 mW was obtained with T=6% output coupler, corresponding to an optical-to-optical conversion efficiency of 11.3% and a slope efficiency of 19.5%. The minimum pulse width was 2.8 ns, the pulse energy and peak power were 39.3 μJ and 14 kW, respectively. Additionally, based on the 1112 nm laser, a 230 mW 556 nm green-yellow laser was achieved within an LBO crystal.

A pulse laser-diode-array (LDA)-pumped, intracavity frequency-doubled Nd: YVO4 laser has been demonstrated. An birefringent filter consisting of a KTP crystal and two Brewster plates(BP) has been used in the system to realize single-frequency output. Up to 72.4 mW average output power is obtained for 800 mW pumping power with an optical-to-optical conversion efficiency of 9.1%. The maximum peak power of the single-frequency green laser is 22.3 W with the pulse width 162μs.

Shaping and filtering of ultrashort pulsed beam at 1.06um by using multilayer volume holographic gratings (MVHGs) is analyzed. The modified multilayer coupled wave theory used to analyze the Bragg diffraction of a system of MVHG is derived. The spectral intensity distributions of the diffracted beam are calculated. The diffraction bandwidth, diffraction pulse duration and the total diffraction efficiency of the filter are also analyzed. Control of the optical pulse shape is accomplished by adjusting the width of the intermediate layer of an optical filter of MVHGs. This pulse shaping technique will be useful in the optical communication and optical computing systems.

We presented a method for measuring the topological charge of a Fractional optical vortex (FOV) by a ring-type multi-pinhole interferometer (RMPI). We retrieved the sampled phase of the FOV passing through a ring-type multi-pinhole plate from the Fourier transform of a single far-field diffraction intensity pattern, and found the phase of FOV around the center approximately be linear with the azimuthal angle, the slope of the phase to the azimuthal angle at the linear part is equal to the topological charge of the FOV. Thus we proposed a method for measuring the l state and determining orbital angular momentum (OAM) of a FOV based on the property.

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