The trapped rainbow

[Arayan]

Abstract : We report on the first experimental demonstration of the broadband "trapped rainbow" in the visible frequency range using an adiabatically tapered waveguide. Being a distinct case of the slow light phenomenon, the trapped rainbow effect could be applied to optical computing and signal processing, and to providing enhanced light-matter interactions.

University professors coated one side of a 4.5 millimetre diameter lens with a 30 nanometre thick coat of gold film, which they then put on a sheet of glass also splashed with a helping of gold. After shining a laser beam at the space between the curved lens and the glass, a rainbow appeared trapped between the elements when looked down on with a microscope. No pot of gold appeared, but a little dancing McNulty, dressed in a leprechaun costume, could be seen under the rainbow.

From: [0911.4464] Experimental observation of the trapped rainbow

 

[VW]

Is that an actual photograph of the experiment? Or a reconstruction? I'm guessing the latter...

 

[Arayan]

Is that an actual photograph of the experiment? Or a reconstruction? I'm guessing the latter...

Yes, the picture is a recostruction, the real one shown in the paper is more accurate but less spectacular

 

[VW]

Still pretty cool though! This an odd and interesting experiment, thanks for sharing...

 

[rangedunits]

Thats a cool experience.

 

[randomlugia]

Really interesting... Just curious, do you know the wavelength of the laser they used?

 

[Arayan]

Really interesting... Just curious, do you know the wavelength of the laser they used?

Was used a light from a multi-wavelength argon ion laser (operating at λ=457 nm, 465 nm, 476 nm, 488 nm and 514 nm) and 633-nm light from a He-Ne laser coupled to the waveguide via side illumination.