Changes

There is a great deal of equipment available for use in holography. While a hologram can be made with very simple equipment, many holographers have $1000s invested into there labs. The most important piece of equipment is the [[Laser|Laser]]. It privides the coherent light source required for making a hologram.

In order to steer and shape the beam holographers use [[Mirror|Mirror]]s, [[Lens|Lens]]es and [[Diffuser|Diffuser]]s. More advanced holography is done with 'split beams'. This involves taking the laser beam in splitting it into two or more beams with a [[Beam Splitter|Beam Splitter]].

A hologram is recorded on a medium. [[Silver Film Comparison Chart|Silver Halide Film]] and [[Dichromated Gelatin Chemistry|Dichromated Gelatin Chemistry]] are the most common mediums for amature holographers and art holographs. Comercial holograms are usually [[Embossed Holograms|Embossed Holograms]] or [[Polymer Film and Processes|Polymer Film and Processes]]. Other exotic materials can record a holographic image. See [[Hologram Recording Materials|Hologram Recording Materials]]. The stability of film is of the upmost importance to recording a hologram. [[Homemade Equipment#Film_Holders|Film HolderHolders]]s are designed to hold film stable to 1/2 wavelength of light for the entire exposure time (or better).

The polarization of a laser beam can be rotated with a [[Wave Plate|Wave Plate]] and this can be quite useful in a large set up.

Every optic will contribute noise to the laser beam. [[Optics Aberrations|Optics Aberrations]], dust and fingerprints will leave a mark on the beam quality. In order to clean the beam a [[Spatial Filter|Spatial Filter]] is used.

All of the optics past the first [[Beam Splitter|Beam Splitter]] need to be held perfectly still. This is acoumplished by designing a [[Optical Bench|Optical Bench]] and [[Optic Mounts|Optic Mounts]] that are very rigid and have no resonances.

The exposure time is calculated by using a [[Light Meter|Light Meter]]. Also the ratio of reference to object beam is measured with a [[Light Meter|Light Meter]].

In order to adjust the exposure energy a [[Shutter|Shutter]] is used to turn the beam on and off. A [[shutterShutter|Shutter]] can be as simple as a black card removed from the beam by hand or a computer controlled device

===Fringe Lockers===

[[Fringe Locker|Fringe Locker]]s

===Beam Blocking===

[[Beam Blocker|Beam Blocker]]s

===Neutral Density Filter===

[[Neutral Density Filter|Neutral Density Filter]]