I went to get new glasses the other day. My eyes are rather out of balance: one eye needs about -8.5 (its uncorrected focal distance for a sharp image is around 6"), the other eye needs about -17 (is twice as bad). The optometrist said that he had to under-correct the weak eye, because the lens distortion would be too great.
So I got to wondering, could practical eyeglasses be made with white-light holograms? A regular hologram is made by exposing an laser interference pattern to film and is displayed by shining one of the reference beams on the developed plate; a white-light hologram is made by exposing film to a display diffraction of the original hologram and does not require a reference beam but displays in any light source.
Holograms reproduce the optical properties of the original subject matter. So a hologram of a mirror works like the mirror and a hologram of a lens acts like that lens. It seems to me that white-light holograms of eyeglass lenses could provide strong corrections from much thinner panes and could be set up the minimize or eliminate the peripheral image distortion of thick, curved lenses.
Has anyone experimented with a concept like this? If a person can adapt to lens distortion, could they not adapt to the quirks of a holographic correction? And since a hologram is just a microscopic diffraction grating, would it even be practical to use computerized etching, to bypass the elaborate holographic process and somehow scribe the correction directly into the panes?
The only holographic eyeglasses I’ve heard of are those gimmick ones with the eyeballs and skulls on the front.
I don’t know if anyone’s tried it. But imagine the R&D and cost of the final product would outweigh the perceived benefits. The tech involved kind of sounds like putting a jet engine on a wheelbarrow.
Yes, they’re possible. See the Wikipedia article on holographic optical elements. I worked at one company where one of the projects was to create an augmented reality display on the inside of a spacesuit helmet, using HOEs to display text and pictures just above the astronaut’s front field of view. This was in the early to mid 1990s. NASA and other agencies were planning the ISS and expected that astronauts would need to do a good deal of EVA to perform maintenance on the station and would need to access instructions and pictures.
Holographic optics are certainly possible and an available commercial item. Holographic standards are frequently used for testing.
Here’s one hitch, though, if you’re looking for eyewear – holographic items are extremely wavelength-sensitive. a device that is extremely similar to a holographic lens was invented long before holography – the Fresnel Zone Plate. The focal distances for each wavelength vary somewhat. If you take a picture using a zone plate instead of a standard lens, it comes out fuzzy. See here:
Not quite. If you make a hologram of a mirror, then the hologram will accurately show the reflection of whatever was in front of the mirror at the time it was taken. It will not, however, show the reflection of anything new you add.
One I sort of wonder about, though: One common hologram is of a microscope sitting on a table. Put your eye to the holographic eyepiece, and you can look through the microscope at whatever it was viewing. But what if you took out the eyepiece before making the hologram? And then held a real eyepiece in the corresponding location above the hologram? Would you see a focused image through it?
Probably not, because a hologram is a plate-surface image, so to hold the eyepiece in alignment with the hologram, you would have to hold it on the other side of the plate, where the hologram image appears to be. Thus, you would be looking through the hologram at the eyepiece behind the plate.
The holograms I’m referring to have the image of the microscope protruding above the plate (with the plate sitting on a table), as though it were a real microscope sitting on the table. So you could still put the eyepiece where it’s supposed to be, in front of the plate.
No, it’s still in a plate, just like any other hologram. Your eyes still have to be lined up with the plate to see anything. The image location is just in front of the plate. It produces some weird effects when you shift your angle so the image crosses the edge of the plate (because you have something behind the image, by parallax, but still obstructing it), but as long as you stay within the appropriate angles, it works.
I remember seeing some of these at a hologram gallery/store in Gatlinburg, Tennessee, some time before 1992 when the whole block burned down. Lots of expensive* holograms on display, but the ones that impressed me enough to still remember more than 20 years later were the microscope and telescope that you could look into. (The microscope one in the link might be the same one I saw–I’m pretty sure that the telescope one is the exact one.)
*The cheapest ones were IIRC over $50 and the most expensive several hundred, not in my high school budget at the time.
I saw very similar large hologram displays in a “hologram museum” in Washington DC as a teenager. I think it closed a few years later. I thought they were the coolest thing, but never saw them again. I always wondered why.
I don’t know. There used to be several Holography Museums around the country in the 1970s. There was one in New York City in Greenwich Village, at which future OSA president Susan Houde-Walther worked briefly. Just before it closed altogether, it moved up to Grand Army Plaza at 59th Street and Fifth Avenue for Christmas time. Then the collection got sold to the MIT Museum, which still holds it, but rarely exhibits it.
I remember visiting a Holography Museum in San Francisco circa 1980. I’ll bet it isn’t there anymore either. I didn’t know about the DC one, but I’m not surprised.
There was a Museum of Holography in Chicago that closed in 2009 after being open for over 35 years. Apparently the collection was saved and put on display for a time after that, but I don’t think it’s open now
Every now and then I see a store selling Holograms, but these never seem to last.
You’d think there would be more interest in holograms. I suspect that diffractive elements as security devices on IDs, Money, and the like have become so commonplace that holograms just seem to be a variation on them, and are ignored. Which is too bad, because Holograms are pretty interesting, and an art form in themselves. I’d love to see the life-sized nude Playmate holograms Hugh Hefner was supposed to have commissioned.