Holography Transmission Equations

With these papers, the geometry of reference and object angles for pseudo-color holograms (multi-colored replay made with a single color laser) of the transmission and reflection configurations can be plotted. Another observation is that if you were making an unslanted grating (the fringes are at right angles to the holoplate, without a tilt) as they more or less show, with thetas 1 and 2 = 22.5 degrees, the fringe spacing would calculate differently than if you plugged in a reference theta of 45 and object theta of 0, even though there is an intra-beam angle of 45 degrees. If you would make a moiré pattern using a pair of sheets of transparency material with parallel lines ruled on them (see the above image), and set a certain angle between them (45 degrees would make the spatial frequency too high to see) and counted the fringes per inch, you would get different counts depending on how you held the ruler.

Source: www.holographyforum.org