Chuck - I've no idea what I'm talking about (as usual) but I would guess
that you don't have to just look for nulling over one wavelength. A bit
like a vernier gauge in the real world (?) you could look over many
wavelengths and if the hundredth pair nulled you would be able to measure
to 1/100th of a wavelength.
Jez
On 15 February 2016 at 03:06, Chuck Norcutt <chucknorcutt@xxxxxxxxxxxxxxxx>
wrote:
> AFAIK the principle way to use interference is nulling the signal. If two
> waves are overlapped and out of phase by 1/2 a wave length the signal will
> be nulled. I'm sure that one can probably measure distances of less than
> 1/2 wave but I doubt that that extends very far.
>
> As Larry Plummer said later: The basis of all this is atom
> interferometry. I don't know what it is but it must be mucho shorter
> distances than wavelengths of light.
>
> Chuck Norcutt
>
>
> On 2/14/2016 4:03 PM, Moose wrote:
>
>> On 2/14/2016 11:13 AM, Chuck Norcutt wrote:
>>
>>> 10**-20 meter, as Dr. Mike noted, is way, way, way smaller than nano.
>>> Nano is only 10**-9. Pico is smaller but still only 10**-12. I still
>>> can't imagine how anyone is measuring that with lasers. UV light
>>> ranges from 10 to 400 nanometers. Much worse, even, than trying to
>>> measure the size of a virus using a meter stick. Anyone got an
>>> explanation?
>>>
>>
>> I know absolutely nothing about all this. It does strike, me, as a
>> matter of simple physics, that interference patterns may reveal things
>> smaller than the wavelengths of the interfering waves - I think. :-)
>>
>> Why are you folks using the double asterisk, 10**-20, instead of the
>> caret, 10^-20 as power notation? The caret is what spreadsheets use, and
>> thus what I've used for the several decades. I can't recall the notation
>> for the mainframe calculating programs I used before that. Before that,
>> it was slide rules ...
>>
>> Speculative and Curious Moose
>>
>> --
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