Features

• Holography Plates for 532 nm and 633 nm
• Record Transmission or Reflection Holograms
• All Development Chemicals Available
• Kits Provide Complete Experimental Setup for Creating Holograms

This page contains Thorlabs' selection of holography plates and developer chemical packets. In addition, we offer a kit that includes plates, developer chemical packets, a laser source, and accessories that are ideal for creating reflection holograms.

Holography Plates
Thorlabs' Holography Plates measure 63 mm x 63 mm (2.48" x 2.48") and are available in either green- (532 nm) or red- (633 nm) sensitive formats. These plates are manufactured using sodium silicate glass with one side coated with a sticky emulsion layer and are sold in packs of 6. Upon exposure to red or green laser light, the emulsion will be exposed, and a hologram can be recorded. Please see the Creating Holograms tab for suggestions on how to make holograms.

Chemicals for Hologram Development
Also available are chemical packets for developing the holography plates. There are two developer chemical sets: one for the red-sensitive plates and the other for the green-sensitive plates; the developer solutions are not interchangeable. These development sets include all the chemicals required to develop 20 holographic plates and only require deionized or distilled water to create the chemical baths. Directions for mixing the chemicals and processing the holographic plates are provided with the chemicals.

Thorlabs sells lasers, mounts, and optics ideal for making holograms. Recommended options for beginning holography are listed on the Creating Holograms tab. Additional options for laser sources, optics, and accessories are listed on the Other Components tab. For our red holography plates, we also offer a preselected assortment of items that can be purchased with one click (see the last two product groupings on this page).

PHG63 Green-Sensitive Holography Plate Graphs

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PHR63 Red-Sensitive Holography Plate Graphs

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This tutorial offers suggestions for making reflection holograms. While the plates offered by Thorlabs are capable of producing both types of holograms, the plates are optimized for creating reflection holograms.

Introduction
In traditional photography, a three-dimensional object is reduced to a two-dimensional image; while the camera is capable of recording the amplitude of the light originating at the object, it yields no information about the phase of the waves. If both the phase and amplitude of the light are recorded, then the image would appear to be exactly the same as the original object when viewed under the same light. Holograms are created by illuminating a photographic plate with two coherent beams: one is a reference beam, while the other either reflects off of or diffracts around an object. For each point on the object, the two interfering beams expose a concentric-ring interference pattern onto the holographic plate. Once developed, illumination of the plate with the same wavelength of light used to expose it will produce a virtual holographic image; this image is formed by light diffraction from the light and dark bands on the plate. This virtual image will have the same intensity and phase information as the light originally incident on the object.*

Creating Holograms
There are two basic ways to create holograms: through reflection or transmission. These designations refer to how the holography plates are arranged with respect to the object. For reflection holograms, the object and the source are on opposite sides of the plate, while for transmission holograms, the source and the object are on the same side of the plate. Since Thorlabs plates are optimized for the recording of reflection holograms, we will focus on a simple setup for this technique.

Reflection Holograms
Thorlabs offers several laser sources that can be used to create holograms. For our red-sensitive plates, our 635 nm fiber-coupled laser source (S1FC635) with an FC/PC-terminated patch cable (P1-630A-FC-1) makes a good source. The light will diverge from the end of the fiber and can illuminate the whole plate at once. Other alternate light sources, such as laser diodes or HeNe lasers, can be used; for more details, please see the Other Components tab above. A recommended light source for our green-sensitive plates is also listed on the Other Components tab.

Figure 1 shows the setup we used to create our holograms. To minimize reflections from the optical table, we placed coins on a matte black surface (e.g., a small piece of TB4 black hardboard). Since holography can suffer greatly from vibrations, it may be beneficial to use our vibration isolation plates (S913B or S913A) along with a sheet of sorbothane (SB12B or SB12A). The light emanating from the fiber tip can be aimed at the plate using our SL20 articulated base. A complete parts list is shown in the table below.

In this configuration, the plate is placed directly next to the object to be imaged, while the laser beam is incident on the other side of the plate. As an initial object, we recommend using coins or another reflective object. In this configuration, the beam directly incident on the plate forms the reference beam, while the beam reflected off of the object interferes with this reference beam to form the interference pattern on the holography plate.

Figure 1: Setup for simple reflection holography, with the holography plate on top of the coins, and the fiber-coupled laser source incident on the plate.
The inset shows the laser light incident on the plate with the room darkened.

The entire setup should be in a fairly dark room, and any light should be blocked from reaching the holography setup. Set up the object and the laser. Turn on the laser, and adjust the beam direction until it covers the objects. Turn off the laser, and place the holographic plate in position with the emulsion (sticky) side of the plate touching the objects. Then turn on the laser with the "enable" button for between 5 to 10 seconds. Disable the laser output, and process the plate.

Developing Holograms
The holograms can be developed using either our PHRKIT chemical packets for red-sensitive plates or our PHGKIT chemical packets for green-sensitive plates. Instructions for developing the holograms are included with the chemical sets.

Viewing Reflection Holograms
The reflection holograms can be viewed with a point source of white light, such as from a flashlight, LED, or unfrosted incandescent light bulb (in Figures 2 and 3, we used a small LED array). There are two ways of viewing reflection holograms. The hologram can be illuminated from the front so that light reflects off of the surface and into the viewer's eye. By adjusting the angle of the light, the hologram can be viewed and will be visible with the wavelength used to record the hologram, as can be seen in Figure 2.

The reflection hologram can also be viewed with a point source located so that the light transmits through the plate. Again, the angle of the light source and the viewer will need to be adjusted. The results are shown in Figure 3.

Transmission holograms must be illuminated with the laser used to expose the plates in order for the image to be visible.

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Figure 2: A reflection hologram viewed by reflecting light off of the plate.

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Figure 3: A reflection hologram viewed by transmitting light through the plate.

*More information on the theory and history of holograms may be found in Hecht, Eugene, Optics, 4th Ed., Addison Wesley, 2002.

The Creating Holograms tab and the Complete Red Reflection Hologram Kit section below suggest a set of components that can be utilized to create reflection holograms. This tab has additional Thorlabs components that can be utilized in the creation of holograms. Thorlabs stocks many other components that could be useful for holography. Our tech support staff is available to answer any questions you may have about configuring a system to record holograms.

Light Sources for Red-Sensitive Plates

In order to easily create holograms, the laser must have a large enough beam to fill the holographic plate. Since a diverging beam is acceptable, we recommend using our fiber-coupled laser source, since the light will spread broadly from the fiber tip and fill the plate if placed at a sufficient distance. If a collimated laser source is used, we recommend using a lens to diverge the light.

Light Sources for Green-Sensitive Plates

For our green-sensitive holography plates, Thorlabs offers two options. A lens is required to diverge the light so that the laser beam fills the plate.

Mounts for Holography Plates

For larger objects where it would be more desirable to have the plate mounted vertically, Thorlabs offers several mounts. For the most stable mounting of the holography plate, the SFH3 filter holder can be used; however, this decreases the clear aperture of the plate to 1.64" (41.7 mm) in the horizontal direction. Our CH2B cylindrical lens mount will allow the entire clear aperture of the plate to be exposed, but the plate may not be as stable, leading to reduced hologram quality. To increase the stability, two CH2B mounts may be used.