I was wondering if it were possible to have some chemical that would change it's state for some duration when hit by a beam of some frequency of light, such that it would change from transparent to reflective/refractive to another beam of light along the same axis of a different frequency, in a way to change the 2nd beam's trajectory? Does something like this already exist? If not, has it been theorised?

                                   // Altered trajectory
  >>beam2>> >>beam1>>     **chemical compound**

The idea is to have a uniform substrate of this compound, where you fire beam1 to saturate a line in it. Once saturated, beam1 would shut off and the line would start to revert, but in section order in which they were transformed.

t0     >>beam1>> [section 0][section 2]...[section n]

tn     >>beam1>> [SECTION 0][SECTION 2]...[SECTION n]

Beam2 would pulse, emitting light along the length of the line, but only at sections that haven't been reverted.

tn+0   >>beam2>> [SECTION 0][SECTION 2]...[SECTION n]

tn+2             [section 0][SECTION 2]...[SECTION n]
tn+n   >>beam2>> [section 0][section 2]...[SECTION n]

If possible, it would enable cheaper displays, since processing wouldn't need complex etching, just highly timed laser diodes.

  • $\begingroup$ Lots of theory on this but no practical invention as far a Is know, maybe one could argue that quantum computing is a form. An EM pulse puts an electron in a certain state and then after computation the state is read out later by another EM pulse. $\endgroup$ Nov 11, 2018 at 1:34
  • $\begingroup$ Take a look at en.wikipedia.org/wiki/Kerr_effect and optical phase conjugate reflection via degenerate 4 wave mixing cns-alumni.bu.edu/~slehar/PhaseConjugate/PhaseConjugate.html $\endgroup$
    – PM 2Ring
    Nov 11, 2018 at 5:05
  • $\begingroup$ will all your requisites it would be much simpler to have a laser fire at a fluorescent screen $\endgroup$ Nov 11, 2018 at 7:39
  • $\begingroup$ @ManudeHanoi, that would require something out of the plane to hit the screen, making it larger. The intention is to keep it as thin as possible. $\endgroup$
    – Adrian
    Nov 11, 2018 at 8:06
  • $\begingroup$ ok I get it now ! $\endgroup$ Nov 11, 2018 at 8:13

3 Answers 3


There are some very straightforward ways to use light to redirect light. Any photorefractive material can be exposed to an interference pattern between two sufficiently bright beams of coherent light to form a transient diffraction grating. Another beam of light incident on the diffraction grating will be diffracted. A diffraction grating can be recorded in photochromic glass or plastic and used the same way. In fact, light can be used to redirect light in any optically nonlinear material using that mechanism.


-one could imagine that the 1st light is absorbed by the compound and the heat makes it expand and therefore change refractive index as in patent US5037169

-The heat could even induce a liquid to gas transition for a stronger effect as in patent US6212308 (B1)

source: optical switch ,wikipedia


Yes, there are ways to change the state of a material with a light beam which could be contrived to change the direction of another beam.

But may I offer another solution? Radiation pressure! Build an optomechanical switch, for which a strong laser beam moves a mirror through radiation pressure, thereby diverting the other beam. It’s not exactly a chemical, but it would get the job done, in principle!


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