Confocal interferometer

SPM, AFM, STM, scanning electron microscopes, transmission electron microscopes, interferometers, confocal microscopes, profilometers, optical microscopes and so on. The given package possesses the whole functions number, which are necessary at images precise analysis, in a number of which the following ones are included ... 

We have undertaken an experiment to try to improve the performance of pulse amplifier experiments. The system is shown schematically in figure 2. It consisted of a continuous-wave C102 dye laser amplified in three stages by a frequency tripled Q-switched NdtYAG laser. The output energy was approximately 2.0 mJ in a 150 MHz linewidth and was up-shifted from the continuous-wave laser by 60 MHz caused by the frequency chirp. This light was then spectrally filtered in a confocal interferometer with a finesse of 40 and a free spectral range of 300 MHz. The linewidth of the filtered radiation was approximately 16 MHz. 

A phase contrast wide field transmission microscope combining the advantages of interferomic and confocal techniques has been developed [155]. Confocal operation is achieved by superimposing speckle illumination of a reference beam in a Mach-Zehnder interferometer with a matched speckle pattern of the object beam. The technique was applied to both dry powders and suspensions and gave good agreement with modelled results. Data acquisition time is less than a millisecond. 

A confocal interferometer, sometimes called incorrectly a spherical FPI, consists of two spherical mirrors M], M2 with equal curvatures (radius r) that are opposed at a distance d = r (Fig. 4.48a) [4.36. 40]. These interferometers... 

The alignment of spherical mirrors is far less critical than that of plane mirrors, because tilting of the spherical mirrors does not change (to a first approximation) the optical path length 4r through the confocal FPI, which remains approximately the same for all incident rays (Fig. 4.50). For the plane FPI, however, the path length increases for rays below the interferometer axis, but decreases for rays above the axis. 

In Sect. 4.2.10 we saw that for a given resolving power the spherical FPI has a larger etendue for mirror separations r > /Ad. For Example 4.19 with D — 5 cm, d = 1 cm, the confocal FPI therefore gives the largest product RU of all interferometers for r > 6 cm. Because of the higher total finesse, however, the confocal FPI may be superior to all other instruments even for smaller mirror separations. 

J.R. Johnson A high resolution scanning confocal interferometer. Appl. Opt. 7, 1061 (1968)... 

A schematic diagram of a commonly used stabilization system is shown in Fig. 5.52. A few percent of the laser output are sent from the two beam splitters BSi and BS2 into two interferometers. The first FPIl is a scanning confocal... 

Interferometers with spherical mirrors can also be used. A frequently used arrangement is used in the con focal interferometer where the mirror separation t equals the radius r of the mirrors (Fig.6.30). The naming of this interferometer is due to the fact that the focal length f of a mirror of radius r is f = r/2. In a confocal interferometer a light ray makes 2 double passes between the mirrors before the primary and the reflected beams again coalesce at the second mirror and can interfere. 

Since this corresponds to a planar interferometer with double the mirror separation the free spectral range for a confocal interferometer is given by... 

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