ThetaStation is an opto-mechanical tool designed to perform spatial selective light delivery with OptogeniX Lambda fibers. An external fiber-coupled visible laser light source is needed to operate the ThetaStation.


ThetaStation allows to confine and manually scan the light emitted by a Lambda fiber at sub-sites of its active length, as shown in Figure below.

By doing so, sub-portions of the tissue region where the Lambda fiber is implanted can be independently probed: this capability gives access to an additional degree of freedom during optogenetics experiments, which has particular relevance when readout techniques extending along one axis are used simultaneously with the site-selective light delivery (e.g. linear microelectrode array).

Before your experiment, it is strongly advised that you build up a calibration table for the optrode, light source, and patch cables you intend to use in your experiment. Please refer to the ThetaStation guide for detailed instructions on how to do this.

LightSpread is a tool based on a Monte Carlo simulation of photon transport in a turbid medium. Within the limits of the assumption of a uniform medium around the light source, results returned by LightSpread are a reasonable estimation of how the light emitted by a flat-cleaved or a tapered fiber propagates in the brain tissue.

Default optical parameters for wavelengths 405nm, 473nm, and 561nm are extrapolated from data reported in J. D. Johansson, Journal of Biomedical Optics 15(5), 057005 (2010) and J. Binding et al., Optics Express 19(6), 4833-4847 (2011).

The software allows for simulation of the emission from tapered fibers of different active lengths and NA (limited to our offer), flat-cleaved fibers of different NA, and spatial selective emission from Lambda-plus fibers. Simulation results can be saved as a .txt file to be analyzed with data analysis software, or as a .npy file that can be opened again from LightSpread.

Minimum requirements:
Operating system: Windows 10 x64
Memory: 8GB RAM
Download the software from here.

1. Wavelength selection allows to use of a preset of tissue scattering parameters. If these parameters are selected by the user, the wavelength value will not affect the simulation.

2. Launching 10 packets of 100,000 photons each is usually a reasonable tradeoff between running time and accuracy of the results.

3. A Gaussian smoothing can be applied to the results by checking the LPF checkbox; the filter order can be specified with an odd integer number.

4. When the Log scale checkbox is checked, results will be visualized with a logarithmic color bar.

5. The zoom tool can be used to select a portion of the colormap.

6. At the end of the simulation LightSpread shows the average power density emitted by the fiber. This value corresponds to the total emitted power divided by the area of the emitter (i.e. the lateral surface of the cone for tapered fibers or the circle surface for flat fibers).

Optogenix Properties

External Light Source

Laser coupled to a single-mode fiber

Source Port


Probe Port



167,3 × 231,9 × 113,1 mm


2.3 kg

Items to be purchased with the ThetaStation:

  • We recommend using Lambda-plus fibers for the best repeatability among different fibers. Lambda-plus fibers are Lambda fibers selected with strict tolerance on both taper length and taper profile for a constant sub-site length among fibers of different batches and are strongly recommended to ThetaStation users.
  • LEDs are OK for full taper operation with standard Lambda fibers, while we recommend Lasers coupled to a single-mode fiber for use with ThetaStation

General recommendations: 

  •  The position and size of light-emitting sub-regions of Lambda fibers, as well as transmission efficiency, need to be calibrated as a function of the micrometer screw position.