Analytical Extension Module for Confocal Fluorescence Spectroscopy

Fluorescence correlation spectroscopy (FCS) is a fluorescence-based measuring method to observe and to analyse movements of molecules in small sample volumes. The analytical module Leica FCS2 can observe molecules in two spectrally separated detection channels. Data evaluation by cross correlation analysis and by photon counting histogram is included. The registration of molecules in the observed volume does not require any adjustment since the Leica FCS2 module is coupled into the confocal scanhead. The perfect and most precise positioning of the scanner in x,y and z direction is guaranteed by the combined optics of both imaging- and FCS system. The use of an acousto-optical beam splitter (AOBS) leads to 30–50% higher yield of fluorescence as compared to other systems.

APD Imaging

The Leica FCS2 module uses highly sensitive avalanche photo diodes (APD) which are also beneficial for image acquisition. Thus, the module is optimally equipped for imaging of very weakly fluorescing samples and observation of single molecules. The Leica FCS2 module is also available as an upgrade to the Leica TCS SP2 spectral confocal and multiphoton microscope.

Technical Specifications

• 2 channel auto- and cross correlation detection and analysis
• 2 channel APD imaging
• Brightness analysis using photon counting histogram (PCH)
• Excitation with UV and VIS lasers (405, 458, 488, 514, 543, 561, 594, 633nm) as well as IR laser (tunable range from 700 to 980nm)
• Positioning of FCS measurement spot via scanner using beam park function
• Filters and beam splitters for APDs are freely exchangeable by user