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We present an optical system designed to capture and observe a single neutral atom in an optical dipole trap, created by focussing a laser beam using a large numerical aperture (N.A. = 0.5) aspheric lens. We experimentally evaluate the performance of the optical system and show that it is diffraction limited over a broad spectral range (∼ 200 nm) with a large transverse field (±25 µm). The optical tweezer created at the focal point of the lens is able to trap single atoms of 87 Rb and to detect them individually with a large collection efficiency. We measure the oscillation frequency of the atom in the dipole trap, and use this value as an independent determination of the waist of the optical tweezer. Finally, we produce with the same lens two dipole traps separated by 2.2 µm and show that the imaging system can resolve the two atoms.

A simple technique for measuring the random noise of an interferometric measurement is presented. The method is based on a filtering technique and the use of a low-pass convolution kernel. It is shown that the method gives a deterministic fraction of the real noise present in the experimental data. The evaluation of the probability density allows the determination of the enlarging constant for specifying the confidence level. Experimental results are reported in the case of moderately noisy and significantly noisy interferometric techniques: phase shifting interferometric testing of smooth surfaces and phase shifting speckle interferometry.

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The refractive index of a germanium prism was measured by two different laboratories for wavelengths in the 8-14-microm range. The sample was a single crystal of known purity and growth history. Index results from the two experiments agreed to within 0.0003 in agreement with the uncertainty analysis presented.