Abstract: A method of measuring the aberrations of a projection lens is disclosed. In this method, a photo-mask is irradiated with an illumination beam through an illumination optics, an inspection mark which comprises a periodic pattern on the photo-mask is imaged on a substrate through a projection optics, and a measurement mark which comprises a periodic pattern corresponding to the periodic pattern of the inspection mark is provided on the substrate. A period P of the periodic pattern of the measurement mark satisfies the following condition:.lambda./{NA(1-.sigma.)}.ltoreq.P.ltoreq.3.lambda./{NA(1+.sigma.)}The measurement mark is measured, and the aberrations of the projection lens are estimated on the basis of the measurement result.

Abstract: The invention relates to the synchronous determination of the absorption, fluorescence, dispersion and refraction of liquids, gases and solids (measurement volumes) with high sensitivity. Radiation of defined wavelength is coupled into a multiple reflection device. The transmitted coupling radiation is measured with a receiver that is located immediately behind a semireflecting mirror. The diffuse reflecting that is directed against the direction of incidence and the radiation which is specularly reflected at the boundary surface with the measurement volume are measured with a receiver that is directed at the measurement volume and located on the coupling mirror. The absorbing power is determined from the reciprocal value of the transmitted coupling radiation. The scattering power and fluorescence power are determined indirectly from the combination of diffuse reflection and transmitted radiation. The refraction is determined from the combination of specularly reflected radiation and transmitted radiation.

Abstract: An optical wavefront analyzer based on the phase-shearing interferometry technique for measuring a wavefront of a light beam is disclosed. The analyzer includes a single phase shifter, a driving device, a pattern receiving device, and a phase reconstructing device. A method of measuring a wavefront of a light beam is also provided for solving the problems of two-axial focusing and phase inconsistency encountered the prior art by employing phase-shearing and phase-shifting techniques to improve the method of optical wavefront mesurement. A non-iterative, path-independent unwrapping methodology is used to deal with a complicated wavefront.

Abstract: An apparatus designed for the testing of a micro-machined mirror that is mounted onto a flying optical head is described. As in the case of normal operation of the head, laser light is coupled into the head using an optical fiber. The light propagates through the head, is emitted from the fiber, reflects off of the steerable mirror inclined at 45 degrees to the fiber axis, and passes through a focusing lens and exits the head. A position sensitive detector (PSD) is placed so as to detect the position of the light spot as it exits the head. Actuation of the mirror's steering capabilities modulates the spot position, which is detected by the PSD and its associated electronics. The profile of the PSD is made small enough to fit in a space between two opposing optical heads on a head stack assembly (HSA) so that the test can be performed immediately prior to the assembly of the disc drive. An array of such PSD's is constructed so that all of heads on an HSA can be tested simultaneously or in a multiplexed manner.

Abstract: An optical flow cell includes a housing having an inlet coupled to an outlet through which a sample fluid material flows. A viewing assembly, carried by the housing, includes a pair of opposed plates having a gap therebetween which is in fluid communication between the inlet and the outlet. One of the plates extends outwardly from the housing for use as a reference point in a fluid sampling device. The flow cell is positioned between a light source and an imaging system to detect particle shape and size as the fluid passes through the viewing assembly.

Abstract: An optical device for measuring reflectance, and, optionally, transmission, of a substrate. The device has first and second toroidal mirrors and first and second optical fibers. The first toroidal mirror directs light from the first optical fiber toward the substrate, which reflects from the substrate and is collected by the second toroidal mirror. The light collected by the second toroidal mirror is focused into the second optical fiber. There are many possible orientations for the fibers and mirrors. The device may also have a fold mirror for directing the light toward the substrate. Optionally, the present invention includes components for measuring transmission of the substrate. The components for measuring transmission may include fibers and toroidal mirrors. Preferably, reflectance and transmission are measured at the same location. If a fold mirror is used, the fold mirror has a gap to allow transmission measurements to be performed at the same location as reflectance measurements.

Abstract: A method and apparatus for testing the configuration of an optical element includes an optical test-set having a holographic optical element designed to obtain a null wave front at the surface of an optical element under test; an interferometer for viewing the test-set, the optical test set and interferometer having optical distortions; and a distortion verification grid (DVG) located in the optical test-set, the DVG comprising a thin opaque sheet of material having a predistorted array of asymmetric holes arranged such that the image of the array of holes formed by the interferometer will be regular and the images of the holes will be symmetric when the optical distortions have been correctly understood and accounted for in the design of the DVG and the distortion correction function.