Ultrasound

light can be redirected by IR, and very strong Low Freq, but ultrasound seems impossible.  Light itself can also act as a particle in behavior.

But there is a way to use ultrasound transceivers to emit a low frequency sound, before, only high frequencies were emitable through an ultrasound node. Now. Anything from drum n bass to vocal speech can be transmitted and heard as if it were right next to the thing it was being aimed at. Would this not be a possible working solution, to use the ultrasound to emit a low frequency to hold or slow the light enough for a slight borderline image. Also. The aim isn't to redirect the light. It's to sustain it, a minute amount in a barrier made using sound long enough or frequently enough so that an image can be seen without the image going completely through and nothing being held.

Thank you for replying btw, much appreciated .

AndAG

I guess I am lost... nothing would be visually seen if light was actually "trapped", except for pure black.  I think you are describing delay of light; but that borders on the theory of time.  If slow anything down, it changes the spectrum. If it is not moving, it is not EM energy.  My big question is WHY?

You can bend light by creating a grating at the scale of the wavelength. Interference between the waves will then cause the light to diffract by certain amounts.

The fun thing is that you can create such a grating in a crystal by making waves go through the crystal. (someone suggested standing waves above, as I understand it, the project I was involved in did it with running waves). The frequency needs to be pretty high. We were working with 100MHz sound waves. Oh and we were using 10.8 micron IR light, so you probably need gigaHertz sound waves for visibile light. Good luck.

are you suggesting that we project an image into a crystalline object and let the resulting image display onto the ultrasound barrier. Or to fire ultrasound into the crystal in order to create that grating. The aim of this is to have an image in the air without the use of fog or a material that will stay in a strict size eliminating the actual "middleman". Hopefully you can see what we're trying to do. Thank you for replying. Everything said will be taken into account.

Yours

AndAG

Your original "problem description" was pretty "vague" Your additions were equally vague. You are getting different answers to different possible interpretations of your question.

Light will go straight unless it is bent (refracted) or bounces (reflected) by some means. Thus it is not possible to project an image in "thin air", as the movies like us to believe.

It /is/ possible to have a piece of say glass have "pass through" and "absorption" areas in a very very fine pattern to create the interference pattern exactly like that of an object that would be behind that glass. A hologram.

Yes: I was talking about firing the ultrasound into the crystal to create a grating.

to get rid of anything vague. We want to create a mid air hologram using light/air/sound no physical material in-between the light and the sound of thing creating the barrier or interference section. Like in the paper I linked we want to create what is on the image. Not just the touchable, invisible shape . I appreciate all the replies.

AndAG

to get rid of anything vague. We want to create a mid air hologram using light/air/sound no physical material in-between the light and the sound of thing creating the barrier or interference section. Like in the paper I linked we want to create what is on the image. Not just the touchable, invisible shape . I appreciate all the replies.

AndAG

I didn't read the articles you linked, but one of them is about creating a touch feedback for people wearing VR glasses. This does nothing "special" with the light: it makes "touch" sensation for a user in midair using ultrasound.

With our (the human race) understanding of physics, what you want cannot be done.

I take that back: Mount five 4Tpixel 1m x 1m LCD screens in a cube form. (you  need about 2Mx2M resolution, or maybe a bit more). Your users will watch the show through the "open" side of the cube. I'm not sure if we've got all the math boiled down enough to calculate the setting of the 20 million million pixels to generate an image though. The good news is that even if the displays are monochrome you can probably create the sensation of colors.

According to physics it CAN be cone, but practical limitations make it impossible to achieve.