Holography Jeremy Ritter Department of Physics University of Texas

Overview ● Demonstrate – Coherence – Interference ● Create Holograms – Holographic camera – Developing

Dennis Gabor ● Born 1900 – Budapest, Hungary ● Holography, 1947 – British Thomson Houston – Electron microscope resolution ● Nobel Prize, 1971

Coherence ● Monochromatic ● Constant Amplitude ● Coherence Length – Length over which the wavelength does not change significantly

Interference ● Superposition ● Relative phase difference ● Interference pattern

Laser ● 1 st working laser – Theodore Maiman, 1960 ● 1 st laser holograms – Leith/Upatnieks, 1963 ● Coherence – Common lasers have coherence lengths of a few centimeters up to several meters

Transmission Hologram ● Reference and object beams on the same side ● Emulsion molecules line up perpendicular to the plane ● Reconstructing beam is transmitted through as the object beam

Reflection Hologram ● Reference and Object beams on opposite sides ● Emulsion molecules line up parrallel to the plane – Interference pattern widens as it dries – Reconstructed with white light

Vibration and Stability ● Isolation table – Heavy marble base – Steel isolation table ● Optical instruments – Notched stands for 3 points of contact – Secured on 2 sides ● Even small vibrations can destroy a hologram

Laser Specs ● Uniphase – Helium-Neon (HeNe) gas laser – 633nm wavelength (red) – 5mW maximum output power – 30cm coherence length

JD-4 Developer ● BB640 and PFG-03M photographic plates

Developing Process ● No ambient light ● Green flash light only

Configuration 1

Results

Configuration 2

Conclusions ● Minimize vibrations – Secure optical instruments – Better plate holder ● Photographic supplies – New plates in good condition – Adequate developer chemicals