Interferometer Fizeau

The external geometric differential delay (see below) of an off axis source is exactly balanced within a Fizeau interferometer, resulting in fringes with the same phase on top of each source in the field. The position of a source may differ from the position of zero OPD in a Michelson interferometer depending on how dissimilar entrance and exit pupils are. The fringe contrast of off-axis sources also depend on the temporal degree of coherence of the detected light. 

Four materials have been certified for thermal expansion SRM 731, borosili-cate glass (80 to 680 K) SRM 736, copper (20 to 800 K) SRM 737, tungsten (80 to 1800 K) and SRM 739, fused silica (80 to 1000 K) (see Fig. 2). The temperature range over which the tungsten is certified is expected to be extended to 2800 K. The thermal expansion of these materials at temperatures below 1000 K was determined with a Fizeau interferometer [ ]. At the higher temperatures, a twin-telemicroscope technique [ ] was used. All these SRMs are in the form of rods, 6 mm in diameter, and are provided in various lengths. 

Figure 5 shows the Fizeau interferometer with a flat reference surface testing the front surface of flat part. Transmissive windows can be tested, as in the Twyman-Green (Fig. 4). The reference flat can be replaced with a system of beam shaping optics including a final curved reference surface. In this configuration, the Fizeau can be used to test a curved surface whose center of curvature is...

Measurement of retroreflectors and prisms Fizeau interferometers have been available... 

The two nearly plane-parallel surfaces of the film constitute a Fizeau interferometer which produces interference fringes in the reflected light [40]. The fringes are lines of constant film thickness. Film drainage data were acquired by generating monochromatic light by means of an interference filter (k= 505 nm) or with a FieNe laser X= 632.8 nm). 

The different types of wavemeters for very accurate measurements of laser wavelengths are based on modifications of the Michelson interferometer [184], the Fizeau interferometer [185], or on a combination of several Fabry-Perot interferometers with different free spectral ranges [186-188]. The wavelength is measured either by monitoring the spatial distribution of the interference pattern with photodiode arrays, or by nsing traveling devices with electronic counting of the interference... 

As mentioned above, the design of the standard cuvettes allowed us to use them as the working cells of a Fizeau interferometer. However, imperfection of fabricated cuvette cases made it impossible to adjust the cuvettes to a band of infinite width. The adopted adjustment procedure produced an optical wedge of 10 bands for cuvette N2 and of 150 band for cuvette Nl. The bands were parallel to the illuminated facet. 

Fig. 4.69. Zerodur mirrors form the reference surface in a Fizeau interferometer of highest accuracy...

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