Writing computer-generated holograms have been achieved by using a near infrared femtosecond laser selective ablation of metal film deposited on glass substrate. The diffraction features with data reconstruction of the fabricated computer-generated holograms were evaluated. Both transmission and reflection holograms can be fabricated in a single process. The process requires no mask, no pre- or post-treatment of the substrate.

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A hexagonal array not only is a nature-preferred pattern but also is widely used in optoelectronical materials and devices. We report a simple method of hexagonal array illumination based on the Talbot effect that has a theoretical efficiency of 100%. An experimental efficiency of 90.6% with a binary phase (0, pi) hexagonal grating is given. This method should be highly interesting for applications of hexagonal array illumination in optical devices as well as in other hexagonal cells.

We propose a miniature pulse compressor that can be used to compensate the group velocity dispersion that is produced by a commercial femtosecond laser cavity. The compressor is composed of two identical highly efficient deep-etched transmissive gratings. Compared with prism pairs, highly efficient deep-etched transmissive grating pairs are lightweight and small. With an optimized groove depth and a duty cycle, 98% diffraction efficiency of the -1 transmissive order can be achieved at a wavelength of 800 nm under Littrow conditions. The deep-etched gratings are fabricated in fused silica by inductively coupled plasma etching. With a pair of the fabricated gratings, the input positively chirped 73.9 fs pulses are neatly compressed into the nearly Fourier transform-limited 43.2 fs pulses. The miniature deep-etched grating-based pulse compressor should be of interest for practical applications.

In this paper we propose a very simple layout of multi-shot second-harmonic-generation (SHG) frequency-resolved optical gating (FROG) using three reflective Dammann gratings (Dammann SHG-FROG ) for characterization of the ultrashort optical pulses. One reflective Dammann gratings is used as the beamsplitter and the other two compensate the angular dispersion. Both theoretical and experimental results show that the distortions of the optical pulses introduced by the reflective Dammann gratings are very small. This device should be highly interesting for characterizing the ultrashort pulse.

A technique for simultaneous beam combination and aperture filling of a coherent laser array that uses a conjugate Dammann grating is proposed. It can convert light from a coherent laser array into a single-lobed far field with high quality. An experiment with a simulated 5 ϫ 5 2D coherent laser array using an aperture mask has been performed. The feasibility of the proposed scheme is verified. It provides an important basis for achieving a high-power and high-brightness laser beam from an actual coherent laser array.

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