Optical Fibers

The Thomas RECORDING Optical Fibers consist of a core glass and a cladding also made of glass. The outer shaft diameter of the Optical Glass Fiber is 120µm (other diameters are available on request). The core glass has a diameter of 108µm.

Key features:

  • Biocompatible material
  • Minimal tissue damage while introducing in brain because of double conical fibers
  • Globular light distribution at the conical tip
  • Available for Thomas RECORDING Microdrive systems (e. g. Mini Matrix, Eckhorn Matrix) or other manipulators
  • Thomas Optical Fiber is available with differen tip shapes (Please see Figure 3)
  • Different fiber connectors available
Material: Optical glass
Outer glass fiber diameter: 120µm
Available fiber tip shapes: Conical tips, double conical tips and blunt tips

Tip Types

The Thomas Optical Fiber is available with blunt tip as shown in figure 1 or with a conical tip like shown in figure 2.

Figure 1: Thomas Optical Fiber dimensions. Core glass diameter: 108µm, outer shaft diameter: 120µm, Material: glass

Figure 2: Thomas Optical Fiber conical tip 

Tip Size

The Thomas Optical Fiber with conical tip is available in three different shapes like shown in figure 3.

Figure 3: Thomas Optical Fiber with conical (Tip D) an double conical (Tip A1 & A2) tip shape 

Advantages of Thomas Optical Fibers

The advantage of Thomas conical and double conical fibers is that they do not cause tissue damage when introduced in brain tissue in comparison to blunt glass fiber tips. Furthermore Thomas Optical Fibers have a globular light distribution at the conical tip (see figure 4) in contrast to the cylindrical light distribution of blunt glass fibers.

Figure 4: Globular light distribution of a Thomas Optical Fiber with conical tip shape 


Thomas Optical Fibers are available for use in Thomas Microdrive systems (e.g. Mini Matrix, Eckhorn Matrix, see figure 5) and also for use with other manipulators (see figure 6). 

Figure 5: A single Thomas optical fiber and 6 Thomas microelectrodes loaded to a 7 channel microelectrode manipulator system “Eckhorn Matrix”. The Microdrive is equipped with a special head allowing a concentric arrangement of electrodes and optical fiber. Each electrode and optical fiber are independently moveable to different depths of the brain. Cortical as well as deep brain stimulation/recording experiments are possible. The lateral distance between electrodes and optical fiber is 254µm but can be reduced down to 80µm! 

Figure 6: Thomas Optical Fiber mounted to a small animal stereotaxic instrument electrode holder


[1] Wolfgang Kruse, Martin Krause, Janna Aarse, Melanie D. Mark, Denise Manahan-Vaughan, Stefan Herlitze: Optogenetic Modulation and Multi-Electrode Analysis of Cerebellar Networks In Vivo  PLOS ONE 9(8): e105589. doi: 10.1371/journal.pone.0105589