Monday, November 20, 2006

Old Truths Die Hard

An old, oft-repeated truism: The size of the finest detail that can be resolved is proportional to L/NA, where L is the wavelength of the light and NA is the numerical aperature (related inversely to f number (f/#)).

BUT: Confocal, I5M, and the new 4Pi can go far beyond this. 4Pi resolves detail below 100nm using a system of genius parallel high NA (~1.4) optics and deconvolution.

left-handed material, metamaterial

negative refractive index
"evanescent" waves
optical diffraction limit

Schlieren, shadowgraph and interferometric techniques have been used for many years to study the distribution of density gradients within a transparent medium.

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