Ultrafast pulse shaping modulates perceived visual brightness in living animals

Abstract

Vision is usually assumed to be sensitive to the light intensity and spectrum but not to its spectral phase. However, experiments performed on retinal proteins in solution showed that the first step of vision consists in an ultrafast photoisomerization that can be coherently controlled by shaping the phase of femtosecond laser pulses, especially in the multiphoton interaction regime. The link between these experiments in solution and the biological process allowing vision was not demonstrated. Here, we measure the electric signals fired from the retina of living mice upon femtosecond multipulse and single-pulse light stimulation. Our results show that the electrophysiological signaling is sensitive to the manipulation of the light excitation on a femtosecond time scale. The mechanism relies on multiple interactions with the light pulses close to the conical intersection, like pump-dump (photoisomerization interruption) and pump-repump (reverse isomerization) processes. This interpretation is supported both experimentally and by dynamics simulations.

Spatiotemporal Optical Vortices: Toward Tailoring Orbital Angular Momentum of Light in Full Space-Time

“…This possibility should be based on fully considering various complex effects in the nonlinear process involving ST vortices, such as phase mismatch, group velocity mismatch, absorption or losses, pump depletion, and so on. , Spin-determined transverse OAM beams can also be expected by using flexible metamaterials , or liquid crystal geometric phase devices. , Additionally, it is possible to enhance and exploit transverse spin–orbit angular momentum coupling by studying ST vortices interacting with chiral matter . The time-varying properties of ST vortices may also be used for coherent control over quantum mechanical methods such as ultrafast chemical reactions , and for driving or monitoring the motions of molecules via the so-called Raman-active phonons. , Although it is still too early to predict the roadmap and applications of ST vortices, this burgeoning field is rapidly emerging and is beginning to yield exciting results, which may profoundly change us in understanding and utilizing light in the future.…”

“…46,47 Additionally, it is possible to enhance and exploit transverse spin−orbit angular momentum coupling by studying ST vortices interacting with chiral matter. 48 The time-varying properties of ST vortices may also be used for coherent control over quantum mechanical methods such as ultrafast chemical reactions 49,50 and for driving or monitoring the motions of molecules via the so-called Ramanactive phonons. 51,52 Although it is still too early to predict the roadmap and applications of ST vortices, this burgeoning field is rapidly emerging and is beginning to yield exciting results, which may profoundly change us in understanding and utilizing light in the future.…”