We develop a fiber based probe that is capable of two-dimensional scanning applicable in optical coherence tomography (OCT). Based on the resonance cantilever with asymmetry structure which has two distinguished resonant frequencies orthogonal directions, Lissajous pattern produced suitable for upon sample. Orthogonal resonances are simultaneously excited by single piezo bender actuator one driving signal consisting components corresponding to above-mentioned frequencies. By integrating...

We develop a high speed spectral domain optical coherence tomography (SD-OCT) system based on custom-built spectrometer and non-uniform discrete Fourier transform (NDFT) to realize minimized depth dependent sensitivity fall-off. After precise calibration of the spectrometer, NDFT acquired data is adopted for image reconstruction. The able measure wavelength range about 138 nm with resolution 0.0674 at central 835 nm, corresponding an axial imaging 2.56 mm in air. Zemax simulations fall-off...

Micromirror technology is one of the current research hotspots. In this work, what we believe to be a novel electrostatic 2-DOF micromirror structure with double-biased torsional axes proposed. By introducing internal resonance, synchronous motions two locked frequency ratio under single driving force were achieved within wide range. The mechanical can thus greatly simplified, as well operating band broadened. Also, methods proposed realize density spot acquisition 1:2 ratio. macroscopic...

We propose an efficient direct k-domain interpolation based on spectral phase in swept-source optical coherence tomography (SS-OCT). Both the calibration signal from Mach-Zehnder interferometer (MZI) and OCT imaging Michelson sharing same swept source are detected digitized simultaneously. Sufficient sampling of with uniform k interval directly interpolated derived MZI signal. Depth profile is then obtained Fourier transform data. In vivo human finger skin nail fold conducted. Reconstructed...

The optical absorption properties of graphene wrapped dielectric particles have been investigated by using Mie scattering theory and exact multi-scattering method.It is shown that subwavelength strong in infrared spectra can take place such systems due to the excitation plasmon resonance graphene.The characteristics efficiency are tunable varying Fermi level damping constant graphene, or changing size small particles.For a cluster these particles, also affected separation distance between...

A bifunctional tunable metamaterial composed of pattern metal structure, graphene, and strontium titanate (STO) film is proposed studied numerically theoretically. The dual plasmon-induced transparency (PIT) window obtained by coupling the bright state cut wire (CW) two pairs dark symmetric semiring resonators (DSSRs) with different parameters. Correspondingly, slow light effect can also be realized. When shifting independently, Fermi level graphene strips, amplitudes PIT windows tuned,...

We present a miniaturized precalibration-based forward-viewing Lissajous scanning fiber probe for high speed endoscopic optical coherence tomography (OCT). The is based on an asymmetric cantilever driven by the piezoelectric bender to realize two-dimensional (2D) scanning. stability and repeatability of trajectory tested position sensitive detector (PSD)-based calibration setup. two orthogonal resonant frequencies are measured be 167.2 121 Hz. A 25 µm focal spot formed at working distance 5...

In 2000, Nikishov et al. presented an analytical model for the power spectrum of oceanic turbulence, in which stable stratification seawater is assumed, i.e., eddy diffusivity temperature equal to that salinity, and ratio unity. Until now, all previous studies on light propagation through turbulence were based Nikishov's model. However, salt are different from each other most underwater environments. Very recently, Elamassie established a more reasonable turbulent fluctuations as explicit...

An adaptive total variation method based on the combination of speckle statistics and restoration is proposed developed for reducing noise in optical coherence tomography (OCT) images. The statistical distribution OCT image investigated measured. With measured parameters such as mean value variance noise, restored by method. algorithm was applied to images a volunteer's hand skin, which showed effective reduction quality improvement. For comparison, commonly used median filtering also same...

Resonant nonlinear optical absorption of silver nanoparticles was studied experimentally via open aperture Z-scan using 130 fs, 400 nm laser pulses. Experimental results show that, at low intensity, can exhibit saturated absorption. While high it shows reverse The saturable is explained in terms ground state plasmon bleaching, while the believed to be from two-photon Saturable intensity and coefficient were obtained 1.3×1010 W/m2 3.3×10−10 m/W, respectively. energy relaxation process Ag...

We propose a transit-time based method to ascertain the azimuth angle of velocity vector by spectral-domain Doppler optical coherence tomography (DOCT), so that three-dimensional (3-D) can be quantified. A custom-designed slit plate with predetermined orientation is placed into sample beam create three delay-encoded sub-beams different shape for probing. Based on analysis bandwidth, within 90 degrees range evaluated exploitation complex signals corresponding path length delays. 3-D...

We present a spatial frequency domain multiplexing method for extending the imaging depth range of spectral optical coherence tomography (SDOCT) system without any expensive device. This uses two galvo scanners with different pivot-offset distances in independent reference arms modulation and multiplexing. The contents corresponding to regions sample can be shifted bands. SDOCT provides an approximately 1.9-fold increase effective ranging compared that conventional full-range system....

Convolution kernel-based non-uniform fast Fourier transform (NUFFT) is an effective image reconstruction method for domain optical coherence tomography.By measuring the error, a general finding optimal parameters of kernel function investigated.Performances in terms point spread and computation time are evaluated.The NUFFT with yields signal sensitivity over 40 dB, that decreased by 85% compared conventional oversampling NUFFT.In vivo images finger tissue efficiently reconstructed through...

A high speed swept source optical coherence tomography (SS-OCT) system capable of full-range imaging is presented. Wave-number carrier frequency introduced into the spectral interference signal by a transmissive dispersive delay line (TDODL). High in corresponding to an equivalent distance-shift exploited obtain OCT imaging. Theoretical development conducted with instantaneous function for complete description signal. Performance advantage TDODL-based method over conventional approach where...

The nonlinear refraction of silver nanoparticles (AgNPs) in n-hexane was studied by using the closed-aperture Z-scan technique with a 532 nm nanosecond laser. It found that, AgNPs shows coexistence and transformation from self-focusing to self-defocusing. Specifically, occurs at low excitation intensity, self-defocusing high relatively moderate intensity. experimental results were analysed discussed terms third-order fifth-order refractive effect. is caused positive refraction, induced...

A method based on higher-order cross-correlation is proposed to fetch the Doppler information flow velocity within areas under low signal-to-noise ratio (SNR) by spectral domain optical coherence tomography. The theoretically developed and validated measurement of a moving mirror with known velocities. Standard deviations velocities different SNRs are determined compared those modified phase-resolved method. Measurement flowing particles glass capillary also conducted, maps reconstructed...

A swept-source optical coherence tomography (SSOCT) system based on a high-speed scanning laser source at center wavelength of 1320 nm and rate 20 kHz is developed. The axial resolution enhanced to 8.3 μm by reshaping the spectrum in frequency domain using window function wave number calibration method Mach-Zender Interferometer (MZI) integrated SSOCT system. imaging speed depth range are 0.04 s per frame 3.9 mm, respectively. peak sensitivity calibrated be 112 dB. With developed system,...

We present a spatial frequency domain multiplexing method for extending the imaging depth range of SDOCT system without any expensive device. This uses two reference arms with different round-trip optical delay to probe regions within sample. Two galvo scanners pivot-offset distances in are used modulation and multiplexing. While simultaneously driving sample arm, spectrum acquired two-dimensional OCT spectral interferogram corresponding shallow deep will be shifted bands domain. After data...

In spectraldomain optical coherence tomography the sample is illuminated by a broadband light source, and spectrum of interference between returned from reference mirror detected grating spectrometer. Conventionally, spectrometer comprised diffraction grating, focusing lens, line-scan camera. According to equation angle approximately linearly related wavelength. Thus distribution function at camera nonlinearly dependent on wavenumber. For high-quality image reconstruction, numerical...