Near-field measurement of short-range correlation in optical waves transmitted through random media.
Two-dimensional near-field images of speckle patterns formed by optical waves transmitted through a disordered porous silica glass sample are measured. The corresponding 2D intensity correlation function, C, is extracted. The subwavelength spatial resolution of near-field microscopy allows us to resolve in the spatial distribution of C the expected subwavelength oscillations and to follow their dependence on the excitation wavelength. Finally, we deduce the effective refractive index of the material by fitting the theoretical spatial dependence of C to our experimental results.
Emiliani
V
V
INFM and LENS, Via Nello Carrara 1, 50019 Firenze, Italy. emiliani@lens.unifi.it
Intonti
F
F
Wiersma
D
D
Colocci
M
M
Cazayous
M
M
Lagendijk
A
A
Aliev
F
F
D008027:Light; D008433:Mathematics; D008853:Microscopy / Q000379:methods; D020527:Microscopy, Scanning Probe; D055095:Optics and Photonics; D012031:Refractometry; D012822:Silicon Dioxide / Q000737:chemistry
D012822:Silicon Dioxide