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The design, fabrication, and demonstration of a planar two-dimensional-crossed reflective diffractive grating are proposed to construct a novel optical configuration, to the best of our knowledge, potentially applied for atom cooling and trapping in a magneto-optical trap. Based on the proposed single-beam single-exposure scheme by means of an orthogonal two-axis Lloyd’s mirrors interferometer, we rapidly patterned a ∼ 1 µ m period grating capable of providing a uniform intensity of the diffracted beams. The key structural parameters of the grating including the array square hole’s width and depth were determined, aiming at providing a high energy of the diffracted beams to perform the atom cooling and trapping. To guarantee the diffracted beams to be overlapped possibly, we adopted a polarized beam splitter to guide the optical path of the incident and zero-order diffracted beams. Therefore, one zero-order diffracted beam with a retroreflected mode and four first-order diffracted beams with appropriate optical path constructed a three-dimensional optical configuration of three orthogonal pairs of counterpropagating beams. Finally, three pairs of the counterpropagating cooling laser beams with 9 mm diameter and > 10 % diffraction efficiencies were achieved, and the circular polarization chirality, purity, and compensation of the desired diffracted beams are further evaluated, which preliminarily validated a high applicability for the magneto-optical trap system.

We investigate a novel two-channel grating encoder that can perform simultaneous measurements of six-degree-of-freedom (DOF) motions of two adjacent sub-components of synthetic-aperture optics such as pulse-compression gratings(PCGs) and telescope-primary mirrors. The grating encoder consists of a reading head and two separate gratings, which are attached to the back of the sub-components, respectively. The reading head is constructed such that there two identical optical probes can share the same optical components. The two probes are guided to hit each of the two gratings and can detect six-DOF motions simultaneously and independently. For each probe, the incident beam propagates through both a three-axes grating interferometry module and a three-axes diffraction integrated autocollimator-module, which detects translational and rotational movement, respectively. By combining the two modules it is possible to perform six-DOF measurement for a single point. The common-path configuration of the two probes enable identical responses to environmental variation, which ensures high accuracy.