Zooming in with AFM on a Photonic Band Gap Structure

Photonic Band Gap materials or PBGs are important optical device structures for which NSOM is a critical characterizing tool .

(Left) 20x20um AFM image of the PBG crystal. Tapping mode with 40kHz resonance frequency.The boxed region is imaged to the right in an 8x8um scan.

(Middle)  8x8 um AFM image of the boxed region in the 20 x 20um scan (left).

(Right) 3.1x3.1um image of the boxed region in the 8x8um image to the left.

PBG Topography Correlated with Light Concentration  In this PBG gaps develop between domains.

AFM topographic image of such a gap with a depth of ~3um.	NSOM collection mode image of the same region with PBG illuminated from the bottom with a UV lamp.
	Collage 3D image of AFM topography and NSOM light distribution.  As is clearly seen the light is concentrated in the gap & clings preferentially to the walls.

 NSOM Collection Mode of Guided Light in a PBG

Green light in a domain (bright triangular region left) propagates in a gap that develops between two dark domains seen emanating from the triangular domain.