Re: [Phys-l] photoreceptors

[John Denker <jsd@av8n.com>]

On 11/22/2006 02:32 PM, Rauber, Joel wrote:

> Are the rods and cones in eye fundamentally frequency or wavelength
> detectors?

That's tricky because under normal conditions, there is a one-to-one
correspondence between frequency and wavelength.

So I suppose to make the question more precise, and more operational,
we need to ask what would happen if the receptor were immersed in
some super-high-index fluid, so as to change the frequency/wavelength
relationship.

It seems to me that the answer must be that frequency is far and
away the dominant factor.  That's because the detection happens
at the molecular level, and the molecules are tiny compared
to the wavelength of light.  So the "front end" detector can
be considered pointlike, and therefore insensitive to wavelength.

> Is the answer different for rods vis a vis cones?

No, not different.