Institute of Physical and Theoretical Chemistry

Working group of Prof. Gauglitz

Mach-Zehnder Interferometry

Mach-Zehnder-Interferometry is a label-free detection method wherein a coherent laser beam is coupled into wave guide of an optical chip. The laser beam is split into two arms using a beam splitter. A sensitive surface is covering one of these arms and a difference in refractive indices is caused by binding of analyte to the surface. At the end, the phase shift in between the two laser beams is detected.

Mach-Zehnder-Interferometry offers typical features of label-free detection methods:

  • No disvantages due to labelling of biological samples
  • Time-resolved measurements

And therefore, determining kinetic and thermodynamic constants. In contrast to RIfS, this method suffers from a sensitive temperature dependency, only one parameter (refractive index) contributes to the measurement signal.

 

Literature

  1. Gauglitz, NATO Science Series II: Mathematics, Physics and Chemistry, 2006, Volume 224, Part 1, 217-237, DOI: 10.1007/1-4020-4611-1_11 ISSN 1568-2609
  2. Gauglitz et al., Anal. Bioanal. Chem. 2005, 381(1), 141-155