A fast hardware photon correlator implemented in a field-programmable gate array (FPGA) combined with a compact confocal fluorescence setup. The correlator has two independent units with a time resolution of 4 ns while utilizing less than 15% of a low-end FPGA. The device directly accepts transistor-transistor logic (TTL) signals from two photon counting detectors and calculates two auto- or cross-correlation curves in real time. Test measurements demonstrate that the performance of our correlator is comparable with the current generation of commercial devices.The sensitivity of the optical setup is identical or even superior to current commercial devices. The FPGA design and the optical setup both allow for a straightforward extension to multi-color applications. This inexpensive and compact solution with a very good performance can serve as a versatile platform for uses in education, applied sciences, and basic research.
- Two-channel implementation based on the Xilinx SP605 board (1 Mbyte)
- Improved four-channel implementation based on the Xilinx ATLYS board (1 Mbyte)
Source code is available upon (please briefly indicate your intentions)
Kalinin, S., Kühnemuth, R., Vardanyan, H., Seidel C. A. M. A 4 ns hardware photon correlator based on a general-purpose FPGA development board implemented in a compact setup for fluorescence correlation spectroscopy. Rev. Sci. Instrum. 83, 096105 (2012); doi: 10.1063/1.4753994