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.

Numerical aperture NA and partial coherence sigma optimization in optical lithography is investigated for 100 nm dense lines under annular illumination and quadrupole illumination. Depth of focus (DOF) is calculated at different NA and sigma settings using PROLITH software. Based on the calculations of DOF, the NA and sigma settings are optimized by finding the values to maximize the DOF. At the optimum NA and sigma settings for 100 nm dense lines, the imaging performance is analyzed for semi-dense and isolated lines.