THORLABS OCS1300SS, User Manual

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Swept Source OCT System Chapter 2: System Description
Rev H, June 3, 2011 Page 10
The sample is placed on a stage, providing XY and rotational translation. An integrated CCD camera in the probe
provides a conventional microscopic view of the sample which aids sample alignment. A pair of XY galvo mirrors
scans the beam across the sample surface creating 1D, 2D, or 3D images.
Figure 2 Schematic of SSOCT System
The schematic of Thorlabs’ OCS1300SS OCT system is as follows: the swept laser source (SS), fiber coupler
(FC), polarization controller (PC), circulator (CIR), collimator (C), adjustable pinhole variable attenuator (AP), and
mirror (M).
2.3.1. Data Acquisition
In the Thorlabs SSOCT, the interference signal is detected using a high-transimpedance, gain-balanced
photodetector that suppresses the DC and autocorrelation noise in the interference signals. A 14-bit, high-speed
digitizer is used to sample OCT interference fringe signals, which are first converted from time to frequency using
a fast Fourier transform (FFT) and then recalibrated. The FFT of the interference signal yields the depth-
dependent reflectivity profile for the OCT image.
All required data acquisition and processing is performed via the integrated software package, which contains a
complete set of functions for controlling data measurement, collection, and processing, as well as for displaying
and managing OCT image files.
2.3.2. Software
The software package within the SSOCT system includes a library of parameters for sample applications. This
system offers a high degree of flexibility by allowing the user to modify experimental parameters to suit
experimental needs. For example, the lateral scanning range and the step width are both user controlled. In
addition, the data sets are easily accessed off-line for further image processing and data analysis.
In the 1D imaging mode, there is no transverse scanning of the beam in the sample arm. The recalibrated
interference fringe signals and the Fourier transformed point spread functions are displayed in real time, which
aids optimization of the signal and system parameters. In the 2D imaging mode, the beam is scanned in one
direction and cross-sectional OCT images are displayed in real time. The software provides flexible control of
image size, brightness, contrast, and the A-line average. For the 3D imaging mode, the probe beam is
sequentially scanned across the sample surface area, and the 3D volume data set under this area is acquired,