Deflection of ultra slow light under gravity
| dc.creator | Kumar, N. | |
| dc.date | 2007-10-01 | |
| dc.date | 2007-12-27 | |
| dc.date.accessioned | 2026-07-07T08:51:03Z | |
| dc.date.available | 2026-07-07T08:51:03Z | |
| dc.description | Recent experiments on ultra slow light in strongly dispersive media by several research groups reporting slowing down of the optical pulses down to speeds of a few metres per second encourage us to examine the intriguing possibility of detecting a deflection or fall of the ultra slow light under Earth's gravity, i.e., on the laboratory length scale. In the absence of a usable general relativistic theory of light waves propagating in such a strongly dispersive optical medium in the presence of a gravitational field, we present a geometrical optics based derivation that combines {\it the effective gravitational refractive index} additively with the usual optical dispersion. It gives a deflection, or the vertical fall $Δ$ for a horizontal traversal $L$ as \[ Δ= \frac{L^2}{2}\big(\frac{R_{\oplus G}}{R_\oplus^2}\big) n_g \big(\frac{1}{1+n_g\frac{R_{\oplus G}}{R_\oplus}}\big), \] where $R_{\oplus G}/R_\oplus$ is the ratio of the gravitational Earth radius($R_{\oplus G}$) to its geometrical radius $R_\oplus$, and $n_g$ is the group refractive index of the strongly dispersive optical medium. The expression is essentailly that for the Newtonian fall of an object projected horizontally with the group speed $v_g=c/n_g$, and is tunable refractively through the index $n_g$. For $L \sim 1 m$ and $n_g = c/v_g \sim 10^8$ (corresponding to the ultra-slow pulse speed $\sim few \times 1 ms^{-1}$), we obtain a fall $Δ\sim 1 μm$, that should be measurable $-$ in particular through its sensitive dependence on the frequency that tunes $n_g$. | |
| dc.description | 4 pages | |
| dc.identifier | https://arxiv.org/abs/0710.0273 | |
| dc.identifier | http://arxiv.org/abs/0710.0273 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/144806 | |
| dc.subject | Optics | |
| dc.subject | Atomic Physics | |
| dc.title | Deflection of ultra slow light under gravity | |
| dc.type | text |