Interferometer-in-Spectrometer for High-Resolution Optical Coherence Tomography

Ultrahigh-resolution optical coherence tomography provides an axial resolution of 1-2 μm for resolving cellular structures of biological tissues critical for the diagnosis of diseases. However, it requires a relatively large spectral bandwidth which is not supported by the key components of the imaging system. We propose a novel spectral-domain OCT design, termed interferometer-in-spectrometer, which is able to compensate the bandwidth limitations of the grating and the line scan sensor by spectral shaping without compromising the signal intensity and adding the system cost. The advantage of axial resolution and ranging depth over the standard design is experimentally validated using the standard testing method and fresh swine cornea ex vivo. Moreover, opportunities that opened up by this new scheme for improving the performances of spectral-domain OCT are also discussed.