Ultrahigh-resolution full-field optical coherence tomography

Abstract

We have developed a white-light interference microscope for ultrahigh-resolution full-field optical coherence tomography of biological media. The experimental setup is based on a Linnik-type interferometer illuminated by a tungsten halogen lamp. En face tomographic images are calculated by a combination of interferometric images recorded by a high-speed CCD camera. Spatial resolution of 1.8 microm x 0.9 microm (transverse x axial) is achieved owing to the extremely short coherence length of the source, the compensation of dispersion mismatch in the interferometer arms, and the use of relatively high-numerical-aperture microscope objectives. A shot-noise-limited detection sensitivity of 90 dB is obtained in an acquisition time per image of 4 s. Subcellular-level images of plant, animal, and human tissues are presented.

Full-Field Optical Coherence Tomography Based on Hilbert Transform

“…The filtered source spectrum has a bandwidth of 164 nm and it is centered at 0.6 µm. Assuming a Gaussian profile of the spectrum, the theoretical axial resolution of 0.97 µm was calculated 3) . Empirically, the axial resolution was measured by recording a series of en-face tomographic images of a flat silver-coated mirror, while moving the mirror across the focal plane of the objective lens in steps of 0.1 µm with a high precision linear motorized stage.…”

“…2) Recently, full-field optical coherence tomography (FF-OCT) has been studied as a new candidate for high-speed OCT imaging. 3) FF-OCT can measure the internal sub-cellular structures of biological samples by using a two-dimensional image sensor array such as a CCD camera, without doing the troublesome lateral XY scanning. FF-OCT utilizes the interferometric scheme such as a Linnik configuration.…”

Three-dimensional nanoscale imaging by plasmonic Brownian microscopy

“…On the other hand, electron microscopy allows wide-field 3D imaging of nanoscale structures at higher speed but often requires vacuum environment with limited imaging penetration due to electron scattering. Optical tomography and time reversal technique may be an alternative wide-field 3D imaging method, yet exhibit lower spatial resolution in microns due to the diffraction limit [10][11][12]. Plasmonic superlens [13][14][15][16] enables super-resolution optical imaging beyond the diffraction limit but only provides two-dimensional imaging at a smaller area [17].…”

Fourier spectrum analysis of full-field optical coherence tomography for tissue imaging

“…In initial efforts, an infrared light-emitting diode (LED) was used for illuminating a Linnik interference microscope [2][3][4][5]. A thermal light source was then used for illumination [6][7][8][9][10][11]. Because light sources with very short temporal and spatial coherence lengths are used in FFOCT, images at micrometre-scale spatial resolution in three dimensions have been generated for a leucocyte [6], and a fixed human oesophagus epithelium [8].…”

“…A thermal light source was then used for illumination [6][7][8][9][10][11]. Because light sources with very short temporal and spatial coherence lengths are used in FFOCT, images at micrometre-scale spatial resolution in three dimensions have been generated for a leucocyte [6], and a fixed human oesophagus epithelium [8]. Here, the spatially incoherent illumination by using extended thermal light sources is to suppress the crosstalk between the neighbouring image points.…”