1. Articles in category: Broadband Sources

    1-24 of 216 1 2 3 4 5 6 7 8 9 »
    1. Mid-infrared photonics: Spiral superluminescent emitter

      Mid-infrared photonics: Spiral superluminescent emitter

      Superluminescent (SL) light sources, which offer the beneficial combination of a broad emission bandwidth with low temporal and high spatial coherence, have many potential industrial and medical applications. In particular, mid-infrared (MIR) SL light sources that are suitable for use in an optical coherence tomography system would be attractive for…

      Read Full Article
    2. Imaging of spectral-domain optical coherence tomography using a superluminescent diode based on InAs quantum dots emitting broadband spectrum with Gaussian-like shape

      Imaging of spectral-domain optical coherence tomography using a superluminescent diode based on InAs quantum dots emitting broadband spectrum with Gaussian-like shape

      We developed a low-coherence light source based on self-assembled InAs quantum dots (QDs) with controlled emission wavelengths and applied it to optical coherence tomography (OCT) imaging. A current-driven superluminescent diode (SLD) light source including four layers of QDs exhibits a broadband (80-nm-bandwidth) emission centered at approximately 1.2 µm with a Gaussian-like spectral shape at room temperature. Spectral-domain OCT (SD-OCT) using the QD-SLD as a light source was developed and imaging with the SD-OCT was demonstrated. The axial resolution was estimated to be approximately 8 µm in air and no apparent side lobes appeared beside the point spread function, indicating ...

      Read Full Article
    3. Frequency combs in molecular fingerprint region

      Frequency combs in molecular fingerprint region

      Silicon nanowire optical waveguides dramatically broaden mid-infrared frequency comb spectra, scientists report. Frequency combs are commercially available in the visible and near-infrared spectral ranges. The mid-infrared spectral region (2-20?m), however, is still emerging. Many applications in spectroscopy, material science, security and industry process control, or chemical, biological and medical sensing would straightforwardly take advantage of mid-infrared photonics devices of higher performance.

      Read Full Article
    4. High resolution Fourier domain optical coherence tomography in the 2 um wavelength range using a broadband supercontinuum source

      High resolution Fourier domain optical coherence tomography in the 2 um wavelength range using a broadband supercontinuum source

      A 220 nm bandwidth supercontinuum source in the two-micron wavelength range has been developed for use in a Fourier domain optical coherence tomography (FDOCT) system. This long wavelength source serves to enhance probing depth in highly scattering material with low water content. We present results confirming improved penetration depth in high opacity paint samples while achieving the high axial resolution needed to resolve individual paint layers. This is the first FDOCT developed in the 2 μm wavelength regime that allows fast, efficient capturing of 3D image cubes at a high axial resolution of 13 μm in air (or 9 μm ...

      Read Full Article
    5. Supercontinuum generation for ultrahigh-resolution optical coherence tomography at wavelength of 0.8µm using carbon nanotube fiber laser and similariton amplifier

      Supercontinuum generation for ultrahigh-resolution optical coherence tomography at wavelength of 0.8µm using carbon nanotube fiber laser and similariton amplifier

      We demonstrated supercontinuum (SC) generation for ultrahigh-resolution optical coherence tomography (UHR-OCT) in the 0.8 µm wavelength region using an ultrashort-pulse fiber laser system. An Er-doped ultrashort-pulse fiber laser with single-wall carbon nanotubes was developed as the seed pulse source. A 46 fs, highest quality, pedestal-free, clean, ultrashort pulse was generated with a similariton amplifier. Then, a 60 fs ideal ultrashort pulse was generated at a wavelength of 0.8 µm with a second-harmonic generation (SHG) crystal, and a Gaussian-like SC was generated in a photonic crystal fiber. UHR-OCT was demonstrated using the generated SC, and precise images of a ...

      Read Full Article
    6. Noise characterization of supercontinuum sources for low-coherence interferometry applications

      Noise characterization of supercontinuum sources for low-coherence interferometry applications

      We examine the noise properties of supercontinuum light sources when used in low-coherence interferometry applications. The first application is a multiple-scattering low-coherence interferometry (ms2/LCI) system, where high power and long image acquisition times are required to image deep into tissue. For this system, we compare the noise characteristics of two supercontinuum sources from different suppliers. Both sources have long-term drift that limits the amount of time over which signal averaging is advantageous for reducing noise. The second application is a high-resolution optical coherence tomography system, where broadband light is needed for high axial resolution. For this system, we compare ...

      Read Full Article
    7. Supercontinuum optimization for dual-soliton based light sources using genetic algorithms in a grid platform

      Supercontinuum optimization for dual-soliton based light sources using genetic algorithms in a grid platform

      We present a numerical strategy to design fiber based dual pulse light sources exhibiting two predefined spectral peaks in the anomalous group velocity dispersion regime. The frequency conversion is based on the soliton fission and soliton self-frequency shift occurring during supercontinuum generation. The optimization process is carried out by a genetic algorithm that provides the optimum input pulse parameters: wavelength, temporal width and peak power. This algorithm is implemented in a Grid platform in order to take advantage of distributed computing. These results are useful for optical coherence tomography applications where bell-shaped pulses located in the second near-infrared window are ...

      Read Full Article
    8. Broadband fiber-optical parametric amplification for ultrafast time-stretch imaging at 1.0 um

      Broadband fiber-optical parametric amplification for ultrafast time-stretch imaging at 1.0 um

      We demonstrate a broadband all-fiber-optical parametric amplifier for ultrafast time-stretch imaging at 1.0 μm, featured by its compact design, alignment-free, high efficiency, and flexible gain spectrum through fiber nonlinearity- and dispersion-engineering: specifically on a dispersion-stabilized photonic-crystal fiber (PCF) to achieve a net gain over 20 THz (75 nm) and a highest gain of ∼ 6000 (37.5 dB). Another unique feature of the parametric amplifier, over other optical amplifiers, is the coherent generation of a synchronized signal replica (called idler) that can be exploited to offer an extra 3-dB gain by optically superposing the signal and idler. It further enhances ...

      Read Full Article
    9. Generation of an octave-spanning supercontinuum in highly nonlinear fibers pumped by noise-like pulse

      Generation of an octave-spanning supercontinuum in highly nonlinear fibers pumped by noise-like pulse

      A supercontinuum generation system is developed, which consists of an erbium-doped fiber ring laser, an erbium-doped fiber amplifier, and a 100-m highly nonlinear fiber. Through nonlinear polarization rotation, the fiber ring laser generates a train of noise-like pulses in the form of repetitive picosecond pulse packets consisting of femtosecond noise-like fine temporal structures. The noise-like pulses are amplified before being sent into the highly nonlinear fiber. As a result, an octave-spanning supercontinuum from 1177 nm to 2449 nm is obtained, which has a 20-dB spectral width of 980 nm. Because of the nonlinearity of the fiber amplifier, the duration of ...

      Read Full Article
    10. The calculation of the coherence time of spectral supercontinuum at the output of the fused silica with different parameters of the initial pulse

      The calculation of the coherence time of spectral supercontinuum at the output of the fused silica with different parameters of the initial pulse

      In this paper the dependence of the coherence time of a femtosecond spectral supercontinuum from different initial pulse parameters - wavelength, peak intensity and duration is studied. The obtained dependences and ratio of the coherence time of the pulse to the duration of the pulse at the output are analyzed. It is shown that in the case of femtosecond spectral supercontinuum generation in fused silica in the areas of normal, anomalous and zero group velocity dispersion, with an increase of the central wavelength of the femtosecond laser pulse at the input, the coherence time of the radiation with ultra-wide spectrum is ...

      Read Full Article
    11. Supercontinuum generation in silicon nanowire embedded photonic crystal fibers with different core geometries

      Supercontinuum generation in silicon nanowire embedded photonic crystal fibers with different core geometries

      We design various silicon nanowire embedded photonic crystal fibers (SN-PCFs) with different core geometries, namely, circular, rectangular and elliptical using finite element method. Further, we study the optical properties such as group velocity dispersion (GVD), third order dispersion (TOD) of x and y-polarized modes and effective nonlinearity for a wavelength range from 0.8 to 1.6 μm. The proposed structure exhibits almost flat GVD (0.8 to 1.2 μm wavelength), zero GVD (≈ 1.31 μm) and small TOD (0.00069 ps 3 /m) at 1.1 μm wavelength and high nonlinearity (2916 W -1 m -1 ) at 0 ...

      Read Full Article
    12. Broadband Or MID-INFRARED Fiber Light Sources

      Broadband Or MID-INFRARED Fiber Light Sources

      An optical system for use in an imaging procedure includes one or more semiconductor diodes configured to generate an input signal beam with a wavelength shorter than 2.5 microns that is amplified and communicated through optical fiber(s) to a nonlinear element configured to broaden the spectral width to at least 50 nm through a nonlinear effect. A subsystem includes lenses or mirrors to deliver an output beam having a broadened spectrum to an Optical Coherence Tomography apparatus with a sample and reference arm to perform imaging for characterizing the sample. The delivered output beam has a temporal duration ...

      Read Full Article
    13. Characterizing the resolvability of real superluminescent diode sources for application to optical coherence tomography using a low coherence interferometry model

      Characterizing the resolvability of real superluminescent diode sources for application to optical coherence tomography using a low coherence interferometry model

      The axial resolution is a critical parameter in determining whether optical coherent tomography (OCT) can be used to resolve specific features in a sample image. Typically, measures of resolution have been attributed to the light source characteristics only, including the coherence length and the point spread function (PSF) width of the OCT light sources. The need to cost effectively visualize the generated PSF and OCT cross-correlated interferogram (A-scan) using many OCT light sources have led to the extrinsic evolution of the OCT simulation model presented. This research indicated that empirical resolution in vivo , as well as depending on the light ...

      Read Full Article
    14. Fabrication and Characteristics of Ce-Doped Fiber for High-Resolution OCT Source

      Fabrication and Characteristics of Ce-Doped Fiber for High-Resolution OCT Source

      The fabrication of Ce-doped fibers (CeDFs) is demonstrated by drawing-tower method employing rod-in-tube technique. The fluorescence spectrum of CeDFs with a 16-μm core exhibited a 160-nm broadband emission with 1.45-μm axial resolution. This CeDF may be functioned as a high-resolution light source for optical coherence tomography applications.

      Read Full Article
    15. Yale University Receives NIH Grant for Development of a New Light Sources for Parallel Optical Coherence Tomography

      Yale University Receives NIH Grant for Development of a New Light Sources for Parallel Optical Coherence Tomography

      Yale University Receivesd a 2014 NIH Grant for $201,881 for Development of a New Light Sources for Parallel Optical Coherence Tomography. The principal investigator is Michel Choma. The program began in 2013 and ends in 2015. Below is a summary of the proposed work. The ability of optical coherence tomography (OCT) to perform high-speed, micron-scale, cross-sectional imaging has transformed ophthalmic medicine and has the potential to transform cardiovascular, gastrointestinal, pulmonary, and dermatological medicine. Current OCT systems use raster scanning, a serial method for acquiring depth reflectivity profiles at different locations on a sample. Shifting the paradigm fro serial to ...

      Read Full Article
    16. Numerical analysis of AlGaAs/GaAs multi-quantum well superluminescent diodes

      Numerical analysis of AlGaAs/GaAs multi-quantum well superluminescent diodes

      In this paper, we have investigated numerically AlGaAs/GaAs multi-quantum well superluminescent diodes. In these devices the dependence of optical gain, output power on the cavity length and the density states have been analyzed. It is observed that the optical gain and its FWHM bandwidth increase with increasing the density state. Furthermore, the output power increases with increasing the cavity length, whereas the FWHM bandwidth decreases.

      Read Full Article
    17. Feature Of The Week 6/29/14: Development of a high power supercontinuum source in the 1.7 um wavelength region for highly penetrative ultrahigh-resolution optical coherence tomography

      Feature Of The Week 6/29/14: Development of a high power supercontinuum source in the 1.7 um wavelength region for highly penetrative ultrahigh-resolution optical coherence tomography

      Optical coherence tomography (OCT) is an essential imaging technique especially in ophthalmology. However, the shallow penetration depth of about 1-2 mm limits the expansion of OCT applications. Recently, the OCT systems operating in 1.7 um wavelength region have been demonstrated to improve the penetration depth. In the longer wavelength region, the signal attenuation due to Rayleigh scattering is reduced compared to that in the conventional 0.8-1.3 um wavelength region. In this work, the authors developed a high power supercontinuum (SC) source at a center wavelength of 1.7 um to demonstrate highly penetrative ultrahigh resolution (UHR) OCT ...

      Read Full Article
    18. Short cavity active mode locking fiber laser for optical sensing and imaging

      Short cavity active mode locking fiber laser for optical sensing and imaging

      We demonstrate a highly linear wavenumber- swept active mode locking (AML) fiber laser for optical sensing and imaging without any wavenumber-space resampling process. In this all-electric AML wavenumber-swept mechanism, a conventional wavelength selection filter is eliminated and, instead, the suitable programmed electric modulation signal is directly applied to the gain medium. Various types of wavenumber (or wavelength) tunings can be implemented because of the filter-less cavity configuration. Therefore, we successfully demonstrate a linearly wavenumber-swept AML fiber laser with 26.5 mW of output power to obtain an in-vivo OCT image at the 100 kHz swept rate.

      Read Full Article
    19. Supercontinuum generation in nonlinear fibers using high-energy figure-of-eight mode-locked fiber laser for SD-OCT application

      Supercontinuum generation in nonlinear fibers using high-energy figure-of-eight mode-locked fiber laser for SD-OCT application

      Generation of flat and broadband supercontinum is demonstrated in an all fiber system using the high-energy noise-like pulses from a stable figure-of-eight fiber laser and nonlinear fibers. This SC source is successfully applied to the spectral domain optical coherence tomography (SD-OCT). The axial resolution is significantly improved compared with the case of the superluminescent diode source. SD-OCT imaging is also demonstrated.

      Read Full Article
    20. Maximizing the bandwidth of coherent, mid-IR supercontinuum using highly nonlinear aperiodic nanofibers

      Maximizing the bandwidth of coherent, mid-IR supercontinuum using highly nonlinear aperiodic nanofibers

      We describe in detail a new procedure of maximizing the bandwidth of mid-infrared (mid-IR) supercontinuum (SC) in highly nonlinear microstructured As 2 Se 3 and tellurite aperiodic nanofibers. By introducing aperiodic rings of first and secondary air holes into the cross-sections of our microstructured fiber designs, we achieve flattened and all-normal dispersion profiles over much broader bandwidths than would be possible with simple periodic designs. These fiber designs are optimized for efficient, broadband, and coherent SC generation in the mid-IR spectral region. Numerical simulations show that these designs enable the generation of a SC spanning over 2290 nm extending from ...

      Read Full Article
    21. Supercontinuum generation in optical fibers and its biomedical applications

      Supercontinuum generation in optical fibers and its biomedical applications

      A microstructured optical fiber was first used in 2000 for supercontinuum generation. Since then, enormous progress has been made in understanding, controlling, and marketing fiber-based supercontinuum sources. In particular, biomedical applications of such sources are revolutionizing the field of medical imaging. In this talk I review the recent progress in this area and describe how a supercontinuum can be employed for biomedical imaging using the techniques known as coherent anti-Stokes Raman scattering, stimulated emission-depletion microscopy, and optical coherence tomography.

      Read Full Article
    22. Supercontinuum Promises Game-Changing New Tools for Medicine, Research, More

      Supercontinuum Promises Game-Changing New Tools for Medicine, Research, More

      Supercontinuum generation has already found uses in chemistry and biology, but its discoverer says what's on the horizon is even more exciting. The technology is featured in new freely accessible multimedia presentations published by SPIE, the international society for optics and photonics.

      Read Full Article
    23. Photonic Device And Optical Coherence Tomography Apparatus Including The Photonic Device As Light Source

      Photonic Device And Optical Coherence Tomography Apparatus Including The Photonic Device As Light Source

      Provided is a photonic device in which emission intensity in a short wavelength region is suppressed even in the case of increasing carrier injection density so as to obtain a wide spectrum half-maximum width as well as a high output. The photonic device includes: a first cladding layer; a second cladding layer; and an active layer including an emitting layer and a barrier layer and being provided between the first cladding layer and the second cladding layer, the emitting layer emitting light in a spectrum having a center wavelength λc and a spectrum half-maximum width Δλ, in which at least one ...

      Read Full Article
    1-24 of 216 1 2 3 4 5 6 7 8 9 »
  1. Categories

    1. Applications:

      Art, Cardiology, Dentistry, Dermatology, Developmental Biology, Gastroenterology, Gynecology, Microscopy, NDE/NDT, Neurology, Oncology, Ophthalmology, Other Non-Medical, Otolaryngology, Pulmonology, Urology
    2. Business News:

      Acquisition, Clinical Trials, Funding, Other Business News, Partnership, Patents
    3. Technology:

      Broadband Sources, Probes, Tunable Sources
    4. Miscellaneous:

      Jobs & Studentships, Student Theses, Textbooks
  2. Popular Articles