We present a high-speed spectral domain optical coherence tomography (SD-OCT) system at 830
nm wavelength which is consisted of a fiber based Michelson interferometer and a custom-built
spectrometer. The designed resolution of the spectrometer is about 67.4pm which limits the
maximum detection depth 2.56mm in air. And the 35us exposure time of the high speed line scan
CCD makes real-time imaging possible. Furthermore, a novel method of spectrometer calibration
is put forward. The method can remove the influence of dispersion mismatch, thus accurately
determine the distribution of wavelength on the line scan CCD, which leads to a precise
interpolation and a subsequent better contrast image.
We develop a fast scanning probe for forward-imaging optical coherence tomography (OCT). The
probe is based on the resonant oscillation of a fiber cantilever which has two distinguished resonant
frequencies intrinsic to its geometry. When actuated by piezoelectric bimorph with signals of mixed
frequencies, various two-dimensional traversal scanning patterns are generated. Experiments on
different probe parameters relating to the qualities of the final images- such as the density of the
scanning coverage, frame rate are carried out. For correct image reconstruction, a micro
two-dimensional position-sensitive detector (PSD) is also introduced to record the scanning pattern in
real-time. Preliminary results of OCT imaging with this developed probe are presented.
Optical coherence tomography (OCT) is a recently developed high resolution biomedical imaging method. Fast scanning
speed and miniature probe is benefit for clinical applications of OCT. In this paper we present a method to realize fast
lateral scanning with two-dimensional (2D) resonant scanning pattern. By driving a fiber cantilever with a bimorph
actuator near its resonance, the planar motion of the fiber cantilever may develop to an elliptical motion due to nonlinear
coupling with longitudinal inertia. This effect can be exploited to form 2D scanning pattern. Basic principle relevant to
realization of 2D scanning pattern of the fiber cantilever scanner by 1D actuator, as well as confirming experimental
results are presented. Future work and system configuration on implementing this fiber cantilever scanner in the sample
arm of a fiber-based OCT system is proposed.
A fiber probe that is capable of two-dimensional traversal scanning is developed and implemented to a time-domain
optical coherence tomography (OCT). Due to its geometrical structure, the fiber cantilever of the probe has two intrinsic
resonant frequencies. When the probe is base-excited by signal with two mixed frequencies near the resonances, traversal
scanning pattern is generated with controllable area coverage through fine tuning of frequency ratio and fetching period.
A position sensitive detector is introduced in the probe to record the real-time trajectory of the scanning pattern for image
reconstruction. Fast OCT images of samples including rule, coin and leaf are obtained with the developed probe applied
to our time-domain OCT setup. We envision obtaining rapid three-dimensional imaging with the developed probe in a
Fourier domain OCT system.