Demonstration of Spin-Multiplexed and Direction-Multiplexed All-Dielectric Visible Metaholograms

Multifunctional meta surface holograms that can produce multiple holographic images, are key flat optical devices for real life ultra compact holographic display application. To generate a multiplex metal hologram, we use a straightforward approach in which two different holographic images can be rendered, depending on the speed of light, and the propagation traction. To understand their multiplex metal hologram setup, feature demonstration of both the fabrication process, and optical characterization, and measurement steps are equally important.

Demonstrating the procedure with the Inki Kim will be Dasol Lee, a PhD student from my laboratory. To characterize the pattern deposition by scanning electron microscopy, drop a conductive polymer onto the substrate, and spin code at 2000 revolutions per minute for one minute. Fix the substrate onto the sample holder with carbon tape, and press the air button to vent the load lock chamber.

Place the holder onto the holding rod of the load lock chamber, and press EVAC to evacuate the load lock chamber. To set the stage height and tilting angle, set the Z sensor to eight millimeters, and the T sensor to zero degrees. Press the OPEN button to open the load lock chamber door, and press the holding rod to transfer the holder to the main scanning electron microscope chamber.

Pull out the rod, and press the CLOSE button. Check the vacuum state, and press execute to remove carbon, or dust in the electron gun with an instant high voltage. Blink on in the microscope software to turn on the electron gun with an accelerating voltage of five kilovolts, and click beam alignment to adjust the beam alignment to precisely locate the electron beam in the center position.

Use a stage controller to locate the beam in the center, and click aperture alignment to adjust the aperture, and stigma alignments to make a circular electron beam. Use a stigma controller to make a stable beam just scan on the same spot, and capture scanning electron images with an appropriate focus and stigmata adjustment. When all of the images have been acquired, click OFF to turn off the electron beam, and click Home to return the stage to it's original position.

When the stage is in position, open the door of the main chamber, and push the rod to pick up the sample holder. Press the air button to vent the load lock chamber, and unload the holder. For optical characterization, using a spin multiplexed metal hologram, attach a diode laser module to an adapter that can be plugged into a one inch optical mount, and use a post and a postholder to adjust the height of the diode laser.

Use a clamp to fix the position, and use a one inch rotational mount to assemble the half wave plate. Place the plate in front of the laser module to rotate the linearly polarized light, and mount two mirrors onto individual one inch kinematic mounts. To align the direction of initial beam, place an alignments disc in front of the laser, and set the laser height.

Adjust the two mirrors so that the beam bends twice at 90 degrees in alternating directions, and position the alignment disc near the second mirror. Rotate the knobs to align the light in the center to adjust the angle of the first mirror, and move the alignment disc far from the second mirror. Then rotate the knobs to align the light in the center to adjust the angle of the second mirror.

Repeat the alignment until the light passes through the center of the alignment disc in both places, and place a neutral density filter behind the mirror to control the intensity of light. Place an iris behind the neutral density filter to control the diameter of incident light. Mount a linear polarizer, and a quarter wave plate on its own rotational mount, and place a linear polarizer, and a quarter wave plate behind the iris to make a circularly polarized light.

Attach the fabricated metal surface to a plate with a hole. Mount the plate on the XY translation mount for rectangular optics, and adjust the XY translation mount so that light is directed to the pattern in the sample. Place a lens after the metal surface, and adjust the position of the lens to be placed at the focal length.

Then place a charge coupled device camera after the lens to capture a hologram image. For optical characterization, using a direction multiplexed meta hologram. Place a beam splitter between the quarter wave plate, and the XY translation mount to split the beam into two directions.

Then place another beam splitter between the XY translation mount and the lens. Place two mirrors so that the beam bends twice at 90 degrees and alternating directions, and adjust the beam to be directed into the second beam splitter. Finally, align the light so that the beam radiates the sample correctly in the opposite direction, and place another lens at 90 degrees to the right of the first beam splitter.

Then place a charge coupled device camera to capture a hologram image from the opposite direction. The best way to produce clear spin, and direction where to place two holographic images is to precisely aligned multiple optical components. In this scanning electron microscopy image, fabricated hydrogenated amorphous silicon metal surfaces, can be observed.

A spin multiplexed metal hologram can switch the projected holographic images by simply flipping the handedness of the incident circularly polarized light. Different metal surfaces can produce different responses, depending on whether the light is circularly polarized to the left or to the right. As a result, depending on the input beam polarization states, the information technology University, and Rho laboratory holographic images can be switched in real time with high fidelity.

A direction multiplex meta hologram can switch the projected holographic images by changing the incident light direction. For instance, if the light comes in the forward direction from the substrate side, the holographic Rho lab images can be observed. If the light comes in the backward direction from the meta surface side, the Holographic Information Technology University images, can be visualized.

Because the clearness of the predicted images is very sensitive to the polarization, and direction of the instant light, the component alignment is particularly important for producing clear holographic images. We plan to develop an active metal hologram that combines this multiplexed metal hologram with an active materials platform to easily change the project, the hologram images by external stimuli.