Determine the length and base area of the cylindrical volume within which light received f...

Determine the length and base area of the cylindrical volume within which light received from the sun is coherent. For this purpose, let us assume “good” spatial coherence occurs within a length that is 25% of the maximum value given by Eq. (9-38). The sun subtends an angle of 0.5° at the earth’s surface. The mean value of the visible spectrum may be taken at 550 nm. Express the coherence volume also in terms of number of wavelengths across cylindrical length and diameter.

Equation 9-38