Versatile fiber-coupled system for simultaneous photon correlation spectroscopy and Fabry–Perot interferometry

We demonstrate an experimental setup utilizing fiber-optic detection and coupling of scattered light into existing photon correlation spectroscopy (PCS) and Fabry–Perot (F–P) interferometry systems. The performance of the fiber coupled F–P as a high-resolution interferometer is considered in detail. Several practical issues and limitations are discussed, including the selection of optic and fiber-optic components, collimation, effects of the fiber mode structure and core diameter, and alignment issues. A series of test measurements on standard systems with well known properties shows that the proposed fiber-optic design meets the performance expectations for both PCS and F–P instruments and presents an attractive alternative to the classical pinhole design. © 2004 American Institute of Physics. [DOI: 10.1063/1.1790561]