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HolographyHolography
Gilbert CollinsGilbert Collins& &
Billy HatfieldBilly Hatfield
Physics 173Physics 173
What is a Hologram?What is a Hologram?-A Hologram is a three dimensional image-A Hologram is a three dimensional image
-While standard photography records color and intensity -While standard photography records color and intensity
information, a hologram encodes phase and intensity.information, a hologram encodes phase and intensity.
-A Holographic Image is created using a coherent light source to -A Holographic Image is created using a coherent light source to
create an interference pattern on a film or plate. create an interference pattern on a film or plate.
-When reconstructed, an observer can view a virtual image beyond -When reconstructed, an observer can view a virtual image beyond
the film that contains all possible perspectives of the object that the film that contains all possible perspectives of the object that
available according to the placement of the film.available according to the placement of the film.
Basic EquipmentBasic Equipment-Basic Holograms require just a few basic components:-Basic Holograms require just a few basic components:
••Light Source:Light Source: The light source generally a laser, which provides The light source generally a laser, which provides
monochromatic and coherent light. Different colors of lasers can monochromatic and coherent light. Different colors of lasers can
be used according to the film. be used according to the film.
••Spatial Filter:Spatial Filter: This is a combination of an objective lens and a This is a combination of an objective lens and a
pinhole. The light is focused into a pinpoint by the objective and pinhole. The light is focused into a pinpoint by the objective and
then passes through the pinhole. This creates modes.then passes through the pinhole. This creates modes.
••Aperture:Aperture: The aperture is closed or opened The aperture is closed or opened
accordingly to select the central mode, which accordingly to select the central mode, which
is the bright area in the center the pattern is the bright area in the center the pattern
created by the spatial filter. created by the spatial filter.
--Film:Film: (we’ll get there) (we’ll get there)
Types of HologramsTypes of Holograms-Transmission Holograms:-Transmission Holograms: Use two beams to create the Use two beams to create the
interference pattern recorded on the film.interference pattern recorded on the film.
••A beam splitter divides the laser beam into two parts. One A beam splitter divides the laser beam into two parts. One
becomes the reference beam and the other, the object beam.becomes the reference beam and the other, the object beam.
••The reference beam needs only go to the film. Generally, it is The reference beam needs only go to the film. Generally, it is
suggested that the reference beam intensity be around 3:1 or 4:1 suggested that the reference beam intensity be around 3:1 or 4:1
so use of an ND filter may be necessary. so use of an ND filter may be necessary.
••The object beam passes reflects off of the object before hitting the The object beam passes reflects off of the object before hitting the
film.film.
-Reflection Holograms:-Reflection Holograms: Place the film between the light source and Place the film between the light source and
the object, thus effectively creating two light sources, and an the object, thus effectively creating two light sources, and an
interference pattern.interference pattern.
Advantages/DisadvantagesAdvantages/Disadvantages-Transmission Holograms:-Transmission Holograms: They take up more space, require more They take up more space, require more
equipment, and require more adjustments and fine tuning to equipment, and require more adjustments and fine tuning to
acquire a good hologram. However, the freedom to adjust many acquire a good hologram. However, the freedom to adjust many
more parameters in a transmission hologram makes them a more more parameters in a transmission hologram makes them a more
powerful tool.powerful tool.
-Reflection Holograms:-Reflection Holograms: These are much simpler to create, and These are much simpler to create, and
require little setup and equipment. They are limited in their ability require little setup and equipment. They are limited in their ability
to change relative intensities, and require transparent film. Plates to change relative intensities, and require transparent film. Plates
will not work for reflection holograms. will not work for reflection holograms.
FilmFilm-Holographic film, like photographic film uses a chemical emulsion-Holographic film, like photographic film uses a chemical emulsion
to capture light information. to capture light information.
-There are a variety of holographic films for difference colors of -There are a variety of holographic films for difference colors of
laser light. laser light.
-The particular film used in our experiments is Slavich PFG-01, -The particular film used in our experiments is Slavich PFG-01,
which is red light sensitive. which is red light sensitive.
-Emulsion undergoes a chemical change when exposed to light, -Emulsion undergoes a chemical change when exposed to light,
which then is exploited by the developer and fixer. which then is exploited by the developer and fixer.
DevelopingDeveloping-Basics:-Basics: Film developing is a process that takes exposed film Film developing is a process that takes exposed film
through a set of chemical baths. In virtually all films, there is a through a set of chemical baths. In virtually all films, there is a
developer, a stop bath, a fixer, and a rinse. developer, a stop bath, a fixer, and a rinse.
••The developer causes a reaction that transforms exposed emulsion on the The developer causes a reaction that transforms exposed emulsion on the
film. film.
••The stop bath can be a water or chemical rinse that stops the developer. The stop bath can be a water or chemical rinse that stops the developer.
••Fixer removes the remainder of the unexposed emulsion on the film.Fixer removes the remainder of the unexposed emulsion on the film.
••A final rinse then removes all chemicals from the filmA final rinse then removes all chemicals from the film
••An agent such as PhotoFlo can then be used to enhance drying and An agent such as PhotoFlo can then be used to enhance drying and
decrease spotting on the film.decrease spotting on the film.
-Photographers Formulary JD-2:-Photographers Formulary JD-2: This particular developer works This particular developer works with film used for red-laser holography. It has a two-part with film used for red-laser holography. It has a two-part developer, and a bleach in place of fixer. The stop and final rinses developer, and a bleach in place of fixer. The stop and final rinses are both water.are both water.
Setup: TransmissionSetup: Transmission
Laser (635nm)
SpatialFilter (10x)
Pinhole (15µm)
Object
Holographic Film
Aperture
Silvered Mirror/ Beam Splitter
Nd1 Filter
This is a basic transmission hologram setup similar to the one we This is a basic transmission hologram setup similar to the one we
used in lab. used in lab.
-To minimize the effects of vibrations-To minimize the effects of vibrations
through the floor, we placed 4 raquetballsthrough the floor, we placed 4 raquetballs
under the optical platform to createunder the optical platform to create
a suspension system.a suspension system.
Observer
Laser (635nm)
Developed Film
Virtual Image
Image ReconstructionImage Reconstruction
Laser (635nm)
Developed Film
Virtual Image
Converging Lens
Screen
Image Reconstruction (Pt.II)Image Reconstruction (Pt.II)
Another Type of Hologram...Another Type of Hologram...
Cylindrical HologramsCylindrical Holograms-A Cylindrical hologram uses diverging lenses after the aperture to -A Cylindrical hologram uses diverging lenses after the aperture to create a rapidly diverging beam. Film is placed in the path of this create a rapidly diverging beam. Film is placed in the path of this beam in a cylindrical shape with the target object in the center of beam in a cylindrical shape with the target object in the center of this cylinder. The diverging beam hitting the film essentially this cylinder. The diverging beam hitting the film essentially creates a reference creates a reference
beam while the light beam while the light
hitting the object hitting the object
reflects onto the film reflects onto the film
creating the equivalent creating the equivalent
of the object beam.of the object beam.
-This gives you a 360°-This gives you a 360°
view of the object.view of the object.
Laser (635nm)
SpatialFilter (10x)
Pinhole (15µm)
Aperture
-50mm Lenses
Holographic Film
Object
Cylindrical SetupCylindrical Setup-We used cylinders made of cut-out Nalgene bottles or PVC pipe -We used cylinders made of cut-out Nalgene bottles or PVC pipe
with diameters 3.5”, 4.5” and 8”. with diameters 3.5”, 4.5” and 8”.
-The insides of the cylinders were either painted or covered in -The insides of the cylinders were either painted or covered in
black paper.black paper.
Results
- First Setup
- Exposure times: 3 – 90 seconds
- Different Objects
Results
- Cylindrical Setup
- Exposure times: 60 – 360 seconds
- Various Diameters
- Different Objects
- Different Film
Difficulties
- Hard to establish “controls”
- Very powerful laser needed for
projecting large holograms
Animation Attempts
Goal: To create a multiple frame holographic animation
Strategy: Expose parts of a strip of holographic film like
frames of a movie
Phase 3: Profit!