RJ

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spread the beams out in a horizontal distribution, this is the relevant case.

Therefore

the attenuation factor for this polarization was chosen for the ordinate in the left hand graph.

The two graphs on the right side of this page (figure 5) are analogous respectively to the two on the left except that the index of refraction had been changed from 1.75 to 1.5. The graphs on the next page, figure 6, pertain to the same set of conditions (order -1) as the ones in corresponding positions in figure 5 except that the wedge angle A has been changed from 1° to 2°.

The remaining pairs of figures are arranged in the same manner except that succeeding pairs pertain respectively to orders m = + 1, 2, 3, and 4.

In view of the fact the reflection for the -1 order is independent of A, figures 5 and 6 are identical except for the labeling.

From the examination of these graphs, it is possible to draw several useful conclusions: (1) As we have said before, the maximum attenuation factor and minimum polarization effect angle occur at essentially the same angle of incidence. In order to minimize the polarization error and the error due to uncertainties in the angle of incidence, attempt should be made to use this angle of incidence in experimental situations.

(2) As suggested by the previous theory, this optimum angle of incidence is negative in sign and becomes larger as the beam order increases.

(3) The principal effects of increasing the index of refraction N is to lower the attenuation factor for the beam of any given order and to widen the angular separation between adjacent beams.

(4) Increasing the wedge angle A has little effect upon the attenuation factor of any given beam but it makes the polarization effects more serious. Also the optimum angle of incidence is shifted to larger negative value.

(5) By restricting the wedge angle A to 1° or less and by the use of the optimum angle of incidence it is possible to produce attenuation factors of the order of 400,000 (56 db) with polarization errors of just slightly more than one percent. It is doubtful whether such attenuation factors can be measured or calculated to such an accuracy. Therefore, with attenuation factors of this size it seems unnecessary to go to the complication

of two symmetrically place beam splitters to cancel out polarization effects if proper care is taken.

spread the beams out in a horizontal distribution, this is the relevant case.

Therefore

the attenuation factor for this polarization was chosen for the ordinate in the left hand

graph.

The two graphs on the right side of this page (figure 5) are analogous respectively to the two on the left except that the index of refraction had been changed from 1.75 to 1.5.

The graphs on the next page, figure 6, pertain to the same set of conditions (order -1) as the ones in corresponding positions in figure 5 except that the wedge angle A has been

changed from 1° to 2o.

The remaining pairs of figures are arranged in the same manner except that succeeding pairs pertain respectively to orders m = + 1, 2, 3, and 4.

In view of the fact the reflection for the -1 order is independent of A, figures 5 and 6 are identical except for the labeling.

From the examination of these graphs, it is possible to draw several useful conclusions: (1) As we have said before, the maximum attenuation factor and minimum polarization effect angle occur at essentially the same angle of incidence. In order to minimize the polarization error and the error due to uncertainties in the angle of incidence, attempt should be made to use this angle of incidence in experimental situations.

(2) As suggested by the previous theory, this optimum angle of incidence is negative in sign and becomes larger as the beam order increases.

(3) The principal effects of increasing the index of refraction N is to lower the attenuation factor for the beam of any given order and to widen the angular separation between adjacent beams.

(4) Increasing the wedge angle A has little effect upon the attenuation factor of any given beam but it makes the polarization effects more serious. Also the optimum angle of incidence is shifted to larger negative value.

(5) By restricting the wedge angle A to 1° or less and by the use of the optimum angle of incidence it is possible to produce attenuation factors of the order of 400,000 It is doubtful (56 db) with polarization errors of just slightly more than one percent. whether such attenuation factors can be measured or calculated to such an accuracy.

There

fore, with attenuation factors of this size it seems unnecessary to go to the complication

of two symmetrically place beam splitters to cancel out polarization effects if proper care

is taken.