Abstract
An electro-optic (EO) sensing system for measuring free-space electric fields in the microwave range has been developed. The system is based on a phase modulation heterodyning technique using a Mach–Zehnder interferometer. In one of the arms of the interferometer, an acousto-optic frequency shifter is used to downconvert the frequency of the detected signal in order to discriminate it from parasites emitted at the external electric field frequency. The sensing part is a crystal placed in a Fabry–Perot cavity. The cavity aims at enhancing the sensitivity of the measurements. Cavity-based EO setups already used in the literature propose this sensitivity enhancement at the expense of the frequency bandwidth, whereas our setup allows this without a major impact on the frequency bandwidth. Electric fields are measured at both 15 kHz and 2.4 GHz with cavities of two different finesses; the best EO phase retardation gains obtained with the cavity are 34 and 60, respectively. The minimum detectable electric field is .
© 2013 Optical Society of America
Full Article | PDF ArticleMore Like This
Gwenaël Gaborit, Guillermo Martin, Jean-Louis Coutaz, Lionel Duvillaret, Samir Kassi, and Daniele Romanini
Appl. Opt. 46(11) 2001-2009 (2007)
Lionel Duvillaret, Stéphane Rialland, and Jean-Louis Coutaz
J. Opt. Soc. Am. B 19(11) 2692-2703 (2002)
Maxime Bernier, Gwenaël Gaborit, Lionel Duvillaret, Alain Paupert, and Jean-Louis Lasserre
Appl. Opt. 47(13) 2470-2476 (2008)