Can you design a hologram?
This is one of the most common questions we hear at Spye and it’s one that comes with a long answer. A hologram is the ideal visual display: visible from all angles, 3-dimensional without polarized viewing lenses, and free from the physical framework that often makes full suspension of disbelief difficult in a viewing experience. The complexity in the answer to this question lies in the fact that while we don’t have a commercially available way to generate a true hologram, there are a variety of technologies that will produce a floating image with a similar effect.
Art, culture, and technology have tremendous influence over each other and often, entertainment inspires science to pursue ideas that have been dreamed up on screen. We’ve seen this happen with flying cars from The Jetsons, hoverboards from Back to the Future, and now holograms from Star Wars and, more recently, the 2012 Coachella concert. Cultural reference points like these are often at the heart of our first conversations with customers and these are really fun conversations to have. Chasing science fiction keeps us moving forward in incredible new environmental design directions.
When it comes to creating a floating image, there are a few different options available with varying levels of sophistication. One simple 2-dimensional solution involves a projection system paired with cut-out shapes of projection film applied to glass or acrylic. A matching mask (.png file) is applied to the projection content to ensure that the projector is only sending content to the areas where film has been applied. This mask prevents excess light from blinding viewers on the opposite side of the projection surface. This 2-dimensional solution is quite effective in its ability to break away from standard aspect ratios and rectangular shapes. The installation we completed in the Freehouse restaurant and brewery in Minneapolis is a great example of this.
Taking 2-dimensional illusions a step further, the 150+ year old Pepper’s Ghost system creates a more dynamic display complete with moving content on a transparent screen. The results of a Pepper’s Ghost installation are impressive but they come at the expense of a very delicate system with limited flexibility. The content production process is intensive, the viewing experience is limited to specific angles, and it is widely considered more of a “parlor trick” than a holographic solution. A few advancements have been made recently to remove some of the limitations of the 2-D Pepper’s Ghost. Most commonly, several surfaces are combined to create a “pyramid hologram” but ultimately this is still just several 2-dimensional surfaces rather than a single truly 3-dimensional display. In order to produce a true hologram, it is essential to break into the third dimension.
True holograms are referred to as volumetric displays. These displays consist of voxels (volume + pixel) that occupy a location in a 3-dimensional space rather than pixels on a 2-dimensional plane. While volumetric displays are not yet available at the commercial level, they do exist and the capabilities of these systems are amazing because not only do they produce a 3-dimensional image, they also generate tangible floating objects. Voxels are produced by ionizing air molecules at the focal point of a laser that fires in durations measured in femtoseconds (1 millionth of 1 billionth of a second). This process creates plasma and as the excited electrons in the plasma drop back to their natural energy levels, photons are released as visible light. Touching one of these voxels increases light output and creates shock waves which result in a slight physical sensation.
Limitations of these systems primarily involve safety and scale concerns. As Evan Ackerman of IEEE Spectrum acknowledges, “If lasers and plasma sound like a dangerous way to make a display, that’s because it is” and the volume of a touch-safe femtosecond laser powered display is only eight cubic millimeters. Despite these current limitations, laser powered volumetric displays offer really exciting possibilities for the future of the audiovisual industry. We will certainly be watching as this technology advances and makes its way into the commercial space.