What does a hologram record that an ordinary photograph does not directly record?

What two waves are used to record a basic hologram?

Why is coherent light needed for holography?

Write the intensity formula for two recording beams with intensities \(I_o\) and \(I_r\).

If two equal recording beams arrive in phase, what is the intensity compared with one beam alone?

If two equal recording beams arrive with phase difference \(\pi\), what happens ideally?

How is path difference related to phase difference in holography?

A path difference of \(\lambda/2\) corresponds to what phase difference?

A path difference of \(2\lambda\) corresponds to what phase difference and interference type?

What happens during hologram reconstruction?

Why is reconstruction a diffraction process?

For two symmetric plane waves meeting at angle \(2\alpha\), state the fringe spacing.

Find the fringe spacing for \(\lambda=500\,\mathrm{nm}\) and \(\alpha=30.0^\circ\).

Find the fringe spacing for \(\lambda=600\,\mathrm{nm}\) and \(\alpha=10.0^\circ\).

What happens to hologram fringe spacing if the angle between recording beams is increased?

Why can a hologram give a sense of depth?

Why does blocking part of an ideal hologram not simply remove the corresponding part of the image?

Explain why an ordinary photograph cannot reconstruct a wavefront the same way a hologram can.

A hologram is reconstructed with a wavelength different from the recording wavelength. What qualitative change can occur?

Derive why the recorded intensity contains phase information.