# Redirecting light using light

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.

• 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. Nov 11, 2018 at 1:34
• 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 Nov 11, 2018 at 5:05
• will all your requisites it would be much simpler to have a laser fire at a fluorescent screen Nov 11, 2018 at 7:39
• @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. Nov 11, 2018 at 8:06
• ok I get it now ! Nov 11, 2018 at 8:13