Light reflections off an oscillating reflective surface

This topic was born from a thought that I posted in reply to another topic.

All you sci-wizz's, feel free to contribut on the possability.


Start with White light directed to a reflective mass.

The mass reflects the whole spectrum of wavelengths shown upon it, no theoretical loss applied.

So you observe a white color of the mass as it reflects all the light applied.

BUT..

Lets say you could bolt the mass to a mechanical oscillator, that is variable to the point of Infrared frequencies or higher. (hypothetical, I know, but for the sake of arguement only.)

So I have to ask, will the light wavelengths experience Doppler effect as it hits the mass and is reflected.

IE-the white light will lose the lower blues, and up in succession to the oscillation frequency, becouse the fast-oscillating atoms in the mass, as the light shines upon it, will alter the observed wavelength's reflected off the mass.

Do you understand what I am trying to suggest?

I am thinking about this, and it seems this would be likely at least in theory, and also theoretically, if the mass could be oscillated fast enough, could the white light whole wavelength spectrum be shifted enough upon reflection, that the whole bandwidth of light applied, is returned and observed as infrared or higher, making the fact that none of the light components being absorbed by the mass, and yet none of the light components being returned to the observer, are visually detectable?

Thoughts?

Yes, it's wavelength does get changed if the object moves. It's called relativistic doppler shift. Oscillating would mean that there is a part where you are moving in the direction of the light, a part where you are moving away from the direction of light and a part where you are standing still. The shift changes direction as well. Going from redshifted to not shifted to blueshifted to not shifted to redshift etc. would really get an observers attention.

I also quote my post in the other thread:

... The speed associated with doppler shifts that are visible is so fast that you will be 'blown apart'.

z = Δλ / λ0
v / c = ((z + 1)^2 - 1)/((z + 1)^2 + 1) source

If you want to shift the frequency 50%, then Δλ / λ0 = 0,5, solving for v gives:

v = ((0.5 + 1)^2 - 1)/((0.5 + 1)^2 + 1 ) c
v = 0.38c

That is really really fast.

*gulp*...

...(lets see...add the three...carry the one..)..

OK, so if the problem of the mass staying together at such a freq, could be overcome,..

The observer (with measurement devices, since the human eye is at best good for seeing a frame of video at 1/2 of a second without 'blending' the image, more on this in a sec) would see the rainbow oscillating between infrared and ultra-violet?

Since the eye is not a fast 'frame grabber' so to speak, it is also possible that the observer without equipment and just visual observation, could get 'stuck' in a visual 'refresh rate' of a harmonic of the oscillation frequency, and the mass may appear to be a steady color in the spectrum reflected?

IE- it could turn steady blue to the observer, or red, or maybe outside of the visual range of wavelength, and appear not necessarily invisable or opaque, but a flat not-reflecting black?

Interesting thoughts coming to mind.

Originally posted by smirkley
The observer (with measurement devices, since the human eye is at best good for seeing a frame of video at 1/2 of a second without 'blending' the image, more on this in a sec) would see the rainbow oscillating between infrared and ultra-violet?

Since the eye is not a fast 'frame grabber' so to speak, it is also possible that the observer without equipment and just visual observation, could get 'stuck' in a visual 'refresh rate' of a harmonic of the oscillation frequency, and the mass may appear to be a steady color in the spectrum reflected?

Yes is the answer to the first question. I think that is what will happen, but you have to keep in mind that also the normally infrared and ultraviolet frequencies get shifted. They may become light with frequencies of visible light.

Every eye cell refreshes at a different time. The eye doesn't go on - off - on - off with seeing. It blends all the different signals of the different cells into one continuous signal. You can't get stuck in seeing only the light that is reflected when the object approahes you, if you mean that.

Well I guess I was using the refresh rate of a crt based display, whereas the actual refresh rate of each frame be no more than 1/2 sec, as the eye does not see the frame change as the image is scanned onto the screen.

This becouse the brain cannot 'load' any faster than that, and the image would appear a fluid moving and changing image, without the flicker.

I know a girl that is almost blind, yet she can 'see' the tv refresh screens flickering and it irritates her when the TV is on. I cannot (hardly) see the flicker, she cannot see the tv image, and hardly the tv.

My second,...was suggested, thinking that the eye does not linearly track a moving object, but actually stops many times in it's travel while watching a moving object. (this can be overcome by letting the focus of your eye drift.) Similarly, if you were to watch the light shimmer from the mass, your eye/brain would only be perceiving time-slices of the image. (assuming the brain does not load pixels in a random or non linear order.) And if this succession of time slices occurs at a particular frequency reletive to a harmonic of the oscillating mass, that maybe much of the transitions repeatedly may be missed, and if close to a locked frequency to the harmonic, maybe only perceiving certain hues, or hue ranges.