Balanced detection for interferometry with a noisy source

E C Robinson; J Trägårdh; I D Lindsay; H Gersen

doi:10.1063/1.4729474

Balanced detection for interferometry with a noisy source

Rev Sci Instrum. 2012 Jun;83(6):063705. doi: 10.1063/1.4729474.

Authors

E C Robinson¹, J Trägårdh, I D Lindsay, H Gersen

Affiliation

¹ H.H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL, United Kingdom.

PMID: 22755632
DOI: 10.1063/1.4729474

Abstract

Optical properties of nanostructures depend on size, shape, material, and local environment. These characteristics can be probed interferometrically, given a broadband source. However, broadband supercontinuum sources are intrinsically noisy, limiting the measurement sensitivity. In this article we describe the application of an auto-balancing technique to reduce the noise in a broadband supercontinuum source, thus increasing the signal to noise ratio. We show a noise reduction of 41 dB allowing optical powers as small as 0.01 pW to be interferometrically detected with a 5 ms integration time.