1. Articles in category: Broadband Sources

    1-24 of 284 1 2 3 4 ... 10 11 12 »
    1. Ultrahigh-resolution optical coherence tomography/angiography with an economic and compact supercontinuum laser

      Ultrahigh-resolution optical coherence tomography/angiography with an economic and compact supercontinuum laser

      In this study, a Q-switch pumped supercontinuum laser (QS-SCL) is used as a light source for in vivo imaging via ultrahigh-resolution optical coherence tomography and angiography (UHR-OCT/OCTA). For this purpose, an OCT system based on a spectral-domain detection scheme is constructed, and a spectrometer with a spectral range of 635 − 875 nm is designed. The effective full-width at half maximum of spectrum covers 150 nm, and the corresponding axial and transverse resolutions are 2 and 10 µm in air, respectively. The relative intensity noise of the QS-SCL and mode-locked SCL is quantitatively compared. Furthermore, a special processing algorithm is ...

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    2. Efficient supercontinuum generation enabled by dispersion engineering in a dual-core waveguide

      Efficient supercontinuum generation enabled by dispersion engineering in a dual-core waveguide

      A compact dual-core waveguide is proposed for efficient supercontinuum generation, in which the use of Si-rich nitride and titanium dioxide provides a large enough index contrast for dispersion engineering. Strong anomalous group velocity dispersion is obtained over a wide bandwidth of 1860 nm which greatly reduces the dispersion length. The nonlinear length can also be significantly decreased due to high nonlinear Kerr index of Si-rich nitride. As a consequence, it could facilitate octave-spanning supercontinuum generation from 1160 to 2385 nm in a greatly reduced propagation distance, as short as 165μm . It is more than one order of magnitude shorter ...

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    3. A Step-Index Silicate Nonlinear Fiber With All Normal Flattened Dispersion for Coherent Supercontinuum

      A Step-Index Silicate Nonlinear Fiber With All Normal Flattened Dispersion for Coherent Supercontinuum

      A step-index silicate fiber with all normal flat dispersion was fabricated. Coherent supercontinuum (SC) spectrum spanning 1200 to 2000 nm was generated in a 5 cm silicate fiber pumped at 1560 nm. The numerical simulation result agreed with the experiment result. Also, highly coherent SC spectrum spanning from 1100 to 2100 nm with flatness <7 dB generated in the fiber with 57 kW pumping power according to simulation. The step-index silicate fiber is not only easy to prepare but also a promising candidate to achieve all-fiber structure for coherent SC.

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    4. Numerical investigation on coherent mid-infrared supercontinuum generation in chalcogenide PCFs with near zero flattened all-normal dispersion profiles

      Numerical investigation on coherent mid-infrared supercontinuum generation in chalcogenide PCFs with near zero flattened all-normal dispersion profiles

      We present a novel design of all-normal flat near zero dispersion chalcogenide photonics crystal fiber (PCF) for mid-infrared supercontinuum (SC) generation. The proposed PCF with a core made of As<sub>2</sub>Se<sub>3</sub> glass and uniform air holes in the cladding is selectively filled with As<sub>2</sub>S<sub>5</sub> glass. By carefully engineering the PCF with an all-normal flat near zero dispersion profile, the anomalous-dispersion soliton effects are reduced, enabling broadband highly coherent SC generation. We also investigate the impacts of the pulse parameters on the SC generation. Broadband SCs covering 1 ...

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    5. Highly coherent supercontinuum generation in CS2 infiltrated single-core optical fiber

      Highly coherent supercontinuum generation in CS2 infiltrated single-core optical fiber

      As is generally known, broad-band near-infrared Supercontinuum (SC) is significant for the applications such as pump-probe spectroscopy, nonlinear spectroscopy, frequency combs, or nonlinear optical parametric amplification. We present the first detailed demonstration of approximate near-infrared, octave-spanning SC generation in all-normal dispersion CS2 single-hole liquid core optical fiber (LCOF). By solving the generalized nonlinear Schrödinger equation, the SC at different parameters can be calculated. The influence of important parameters including but not limited to fiber core-diameter, pump wavelength, pump power, and pulse width, on the supercontinuum generation (SCG) of CS2 infiltrated LCOF can be analyzed for optimization of near-infrared SC ...

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    6. Generation and characterization of mid-infrared supercontinuum in polarization maintained ZBLAN fibers

      Generation and characterization of mid-infrared supercontinuum in polarization maintained ZBLAN fibers

      We present mid-infrared (MIR) supercontinuum generation in polarization-maintained ZBLAN fibers pumped by 2 µm femtosecond pulses from a Tm:YAP regenerative amplifier. A stable supercontinuum that spreads from 380 nm to 4 µm was generated by coupling only 0.5 µJ pulse energy into an elliptical core ZBLAN fiber. The supercontinuum was characterized using cross-correlation frequency-resolved optical gating (XFROG). The complex structure of the XFROG trace due to the pulse-to-pulse spectrum instability have been fixed by reducing the length of the applied fibers or improving the quality of the incident pulse spectrum

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    7. Chalcogenide-glass polarization-maintaining photonic crystal fiber for mid-infrared supercontinuum generation

      Chalcogenide-glass polarization-maintaining photonic crystal fiber for mid-infrared supercontinuum generation

      In this paper, we report the design and fabrication of a highly birefringent polarization-maintaining photonic crystal fiber (PM-PCF) made from chalcogenide glass, and its application to linearly-polarized supercontinuum (SC) generation in the mid-infrared region. The fiber was drawn using the casting method from As38Se62 glass which features a transmission window from 2 to 10 µm and a high nonlinear index of 1.13×10-17 m2 /W. It has a zero-dispersion wavelength around 4.5 µm and, at this wavelength, a large birefringence of 6×10-4 and consequently strong polarization maintaining properties are expected. Using this fiber, we experimentally demonstrate supercontinuum ...

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    8. EXALOS Introduces RGB Modules for Augmented Reality and Head-up Display Applications

      EXALOS Introduces RGB Modules for Augmented Reality and Head-up Display Applications

      Schlieren, Switzerland, May 6 th , 2019. EXALOS, the world’s leading developer of visible Superluminescent Light Emitting Diodes (SLEDs), has expanded its product porfolio with the introduction of a compact RGB SLED module that will enable the advancement of micro-display architectures for augmented reality (AR) and head-up displays (HUDs). The RGB module constitutes three SLED chips housed in a 14-pin butterfly package (20.8 mm x 1.7 mm) with a total output power of about 30 mW (~ 10 mW/color), which corresponds to a total luminous flux of 5 lm. The individual chips (635 nm (R), 510 nm (G ...

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      Mentions: Exalos Kevin Hsu
    9. Supercontinuum light source comprising microstructured optical fiber

      Supercontinuum light source comprising microstructured optical fiber

      The invention relates to a microstructured optical fiber for generating supercontinuum light upon feeding of pump light. The light can be incoherent light. The microstructured optical fiber has a first section and a second section, where the first and second sections have one or more different features. The invention also relates to a supercontinuum source comprising a microstructured optical fiber according to the invention.

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      Mentions: NKT Photonics
    10. Supercontinuum noise reduction by fiber undertapering

      Supercontinuum noise reduction by fiber undertapering

      We demonstrate that the Relative Intensity Noise (RIN) of a supercontinuum source can be significantly reduced using the new concept of undertapering, where the fiber is tapered to a diameter that is smaller than the diameter that gives the shortest blue edge, which is typically regarded as the optimum. We show that undertapering allows to control the second zero dispersion wavelength and use it as a soliton barrier to stop the redshifting solitons at a pre-defined wavelength, and thereby strongly reduce the RIN. We demonstrate how undertapering can reduce the spectrally averaged RIN in the optical coherence tomography bands, 500 ...

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    11. Development of a broadband superluminescent diode based on self-assembled InAs quantum dots and demonstration of high-axial-resolution optical coherence tomography imaging

      Development of a broadband superluminescent diode based on self-assembled InAs quantum dots and demonstration of high-axial-resolution optical coherence tomography imaging

      We developed a near-infrared (NIR) superluminescent diode (SLD) based on self-assembled InAs quantum dots (QDs) and demonstrated high-axial-resolution optical coherence tomography (OCT) imaging using this QD-based SLD (QD-SLD). The QD-SLD utilized InAs QDs with controlled emission wavelengths as a NIR broadband light emitter, and a tilted waveguide with segmented electrodes was prepared for edge-emitting broadband electroluminescence (EL) spanning approximately 1–1.3 μm. The bandwidth of the EL spectrum was increased up to 144 nm at a temperature of 25 °C controlled using a thermoelectric cooler. The inverse Fourier transform of the EL spectrum predicted a minimum resolution of 3 ...

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    12. Soliton microcomb based spectral domain optical coherence tomography

      Soliton microcomb based spectral domain optical coherence tomography

      Spectral domain optical coherence tomography (SD-OCT) has become a widely applied minimally invasive technique for bio-medical imaging[1–4], and industrial process control[5]. One of the most commonly used light source for SD-OCT is based on superluminescent diodes (SLD), which provide a low-noise broadband coverage.[6] Recent advances have allowed creating photonic integrated chipscale frequency combs, that provide an attractive alternative illumination scheme for SD-OCT. Yet to date, the use of such soliton micro-combs in OCT has not been demonstrated or considered. Here we explore the use of soliton microcombs in spectral domain OCT. By using photonic chipscale Si3N4 ...

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    13. EXALOS releases NEW Ultrabroadband Superluminescent Light Emitting Diodes for Medical Imaging and Sensor applications

      EXALOS releases NEW Ultrabroadband Superluminescent Light Emitting Diodes for Medical Imaging and Sensor applications

      EXALOS has expanded its portfolio of Superluminescent Light Emitting Diodes (SLEDs) by introducing our new near-IR Combi-SLED modules where multiple SLED devices are spectrally combined to provide an ultra-broadband spectrum. The light output of the SLEDs are collimated using micro-optical collimation lenses, spectrally combined and colinearly aligned through free-space dielectric edge filters and focused into a single-mode fiber. The Combi-SLEDs are especially suited for medical imaging applications such as ultra-high-resolution Optical Coherence Tomography (UHR-OCT) and Fiber Optic Sensor applications thanks to their high output power. large spectral bandwidth and short coherence length. The first product release of such a Combi-SLED ...

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      Mentions: Exalos Kevin Hsu
    14. EXALOS Introduces RGB Modules for Augmented Reality and Head-up Display Applications

      EXALOS Introduces RGB Modules for Augmented Reality and Head-up Display Applications

      EXALOS, the world’s leading developer of visible Superluminescent Light Emitting Diodes (SLEDs), has expanded its product porfolio with the introduction of a compact RGB SLED module that will enable the advancement of micro-display architectures for augmented reality (AR) and head-up displays (HUDs). The RGB module constitutes three SLED chips housed in a 14-pin butterfly package (20.8 mm x 1.7 mm) with a total output power of about 30 mW (~ 10 mW/color), which corresponds to a total luminous flux of 5 lm. The individual chips (635 nm (R), 510 nm (G), and 450 nm (B)) are each ...

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      Mentions: Exalos Kevin Hsu
    15. Noise of supercontinuum sources in spectral domain optical coherence tomography

      Noise of supercontinuum sources in spectral domain optical coherence tomography

      In this paper, we investigate the effect of pulse-to-pulse fluctuations of supercontinuum sources on the noise in spectral domain optical coherence tomography (OCT) images. The commonly quoted theoretical expression for the OCT noise is derived for a thermal light source, which is not suitable if a supercontinuum light source is used. We therefore propose a new, measurement-based OCT noise model that predicts the noise without any assumptions on the type of light source. We show that the predicted noise values are in excellent agreement with the measured values. The spectral correlation evaluated for the photodetected signal when using a supercontinuum ...

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    16. New U of A laser technology shows promise to treat leading causes of blindness

      New U of A laser technology shows promise to treat leading causes of blindness

      AMD damages the retina of the eye and is the leading cause of blindness globally. Glaucoma is characterized by an increase of pressure within the eye that damages the optic nerve, eventually leading to blindness. It’s projected that by 2020, more than 196 million people will be affected by AMD and 76 million people will be affected by glaucoma. The platform Katchinskiy is developing combines femtosecond lasers with optical coherence tomography, a technology for evaluating conditions of the retina, and scanning laser ophthalmoscopy, a method for creating diagnostic images of the retina that enables a high degree of spatial ...

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    17. Supercontinuum in the practice of Optical Coherence Tomography with emphasis on noise effects (Thesis)

      Supercontinuum in the practice of Optical Coherence Tomography with emphasis on noise effects (Thesis)

      Optical Coherence Tomography (OCT) is an imaging modality which has proven, since the early 1990s, its incredible potential. Nowadays, numerous fields of medical investigation, such as Ophthalmology, Dermatology or Cardiovascular imaging, would not be the same without the diagnostic tools bring by OCT. This tremendous development has been supported by industry support through improvement of dedicated components such as lasers, cameras and optics. A great example of this development is the evolution of Supercontinuum (SC) sources. Due to the extremely broad spectrum cover by SC sources, their high power density and high spatial coherence, it seems obvious to use them ...

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    18. Supercontinuum source-based multi-contrast optical coherence tomography for rat retina imaging

      Supercontinuum source-based multi-contrast optical coherence tomography for rat retina imaging

      This study proposed an ultrahigh-resolution multi-contrast optical coherence tomography system integrated with fundus photography for in vivo retinal imaging of rodents. A supercontinuum light source was used in the system, providing an axial resolution of less than 3 µm within 1.8 mm (in the tissue). Three types of tissue contrast based on backscattered intensity, phase retardation, and microvasculature at a capillary level can be simultaneously obtained using the proposed system. Pigmented Long-Evans, non-pigmented (albino) Sprague Dawley, and Royal College of Surgeons rats were imaged and compared. In vivo imaging results were validated with histology.

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    19. Hamamatsu develops bright supercontinuum source

      Hamamatsu develops bright supercontinuum source

      Hamamatsu Photonics has developed a supercontinuum light source, also known the SC light source, that produces higher brightness – approximately 1000 times higher than the company’s own range of xenon lamps. At the same time, the SC source maintains the high stability equivalent to that of xenon lamps by optimizing output conditions and also using a high nonlinear optical fiber as its nonlinear optical material. This source is targeting the market for measuring the complex structure of semiconductor optical measurements. The company added that its official commercial release will be in the spring of 2019. The new SC light source ...

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    20. Wavelength Dependence of Ultrahigh-Resolution Optical Coherence Tomography Using Supercontinuum for Biomedical Imaging

      Wavelength Dependence of Ultrahigh-Resolution Optical Coherence Tomography Using Supercontinuum for Biomedical Imaging

      Optical coherence tomography (OCT) is a noninvasive cross-sectional imaging technique with micrometer resolution. The theoretical axial resolution is determined by the center wavelength and bandwidth of the light source, and the wider the bandwidth, the higher the axial resolution. The characteristics of OCT imaging depend on the optical wavelength used. In this paper, we investigated the wavelength dependence of ultrahigh-resolution (UHR) OCT using a supercontinuum for biomedical imaging. Wideband, high-power, low-noise supercontinua (SC) were generated at λ = 0.8, 1.1, 1.3, and 1.7 μ m based on ultrashort pulses and nonlinear fibers. The wavelength dependence of OCT imaging was ...

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    21. Near-infrared and mid-infrared semiconductor broadband light emitters

      Near-infrared and mid-infrared semiconductor broadband light emitters

      Semiconductor broadband light emitters have emerged as ideal and vital light sources for a range of biomedical sensing/imaging applications, especially for optical coherence tomography systems. Although near-infrared broadband light emitters have found increasingly wide utilization in these imaging applications, the requirement to simultaneously achieve both a high spectral bandwidth and output power is still challenging for such devices. Owing to the relatively weak amplified spontaneous emission, as a consequence of the very short non-radiative carrier lifetime of the inter-subband transitions in quantum cascade structures, it is even more challenging to obtain desirable mid-infrared broadband light emitters. There have been ...

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    22. Flatly Broadened and Highly Coherent Supercontinuum Generation by Induced Modulation Instability in ANDi-PCF

      Flatly Broadened and Highly Coherent Supercontinuum Generation by Induced Modulation Instability in ANDi-PCF

      In this paper, a flatly broadened and highly coherent supercontinuum generation by induced modulation instability in ANDi-PCF is proposed. The numerical results show that the bandwidth of supercontinuun can be increased by increasing the modulation depth and the coherence property of supercontinuum can be improved with the optimal modulation frequency. A highly coherent supercontinuum with the 10 dB bandwidth of 1305 nm and the flatness of less than 10 dB can be obtained when seeding at the modulation depth of 0.3 and modulation frequency of 24 THz.

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    23. Q-switched based supercontinuum source towards low-cost ultra-high resolution optical coherence tomography

      Q-switched based supercontinuum source towards low-cost ultra-high resolution optical coherence tomography

      Supercontinuum (SC) light source is certainly one of the best option for ultra-high resolution optical coherence tomography (UHR-OCT). Over the last few years several demonstrations have been done for each commonly used wavelength range [1-2-3]. Nowadays, SC dedicated to UHR-OCT is a mature technology with turn-key commercially available system [4]. The new challenge to answer for SC source is the cost reduction one. In this study, we demonstrate that a Q-switched based SC (QS-SC) could be an alternative to the current state of the art SC based on a Mode-Locked laser (ML-SC). This QS-SC, whose cost is less than 15 ...

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    24. Evolution of the Supercontinuum Light Source

      Evolution of the Supercontinuum Light Source

      For many applications, coherent light at a single frequency is more than adequate. But having a light source that combines the properties of a laser with the broad bandwidth of an incandescent bulb and a short pulse duration opens up a new realm of possibilities in medical imaging, communications, displays and materials studies. One of most extraordinary discoveries of optical effects came in 1970 from Robert Alfano and Stanley Shapiro 1 . The duo demonstrated the conversion of a narrow band color — for example, green light of short duration — to white color and beyond. This was accomplished by nonlinear effect, and ...

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