Broadband Sources

Tuning of the Stokes scintillations by controlling the longitudinal coherence

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Various imaging techniques such as optical coherence tomography (OCT) and ghost imaging focus on increasing the resolution of the system to enhance the imaging quality. The information of polarization fluctuations of the field can reveal the fine details of the source or object through Stokes correlations. In this study, we provide a framework for the correlation in the fluctuations of Stokes parameters in the longitudinal direction for the general non-collimated fields. We first derive the four scintillation coefficients for a scheme using Gaussian statistics, which are basically the variance of the Stokes parameters. The influence of longitudinal spatial coherence (LSC) and temporal coherence on tuning the scintillation coefficients can be useful in purposely managing the noise of a Stokes parameter. Experimental demonstration of the modulation of the scintillation coefficients owing to frequency and angular spectrum endorse the theoretical findings. The temporal dependence of the...

Novel Optical Measurement and Imaging Technologies using Broadband Light Sources – Special Issue in Frontiers in Physics Journal

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Optical measurement and imaging have been key fields in scientific and technological advancements. Historically, from the development of theories of quantum mechanics and relativity, to the discovery of DNA structure and astronomical events, optical measurement and imaging technologies, such as Michelson interferometer, large-scale space telescopes, high-resolution microscopy and crystallography, played critical roles in identifying key signals, structures, and interactions between light field and various types of materials. Recently, broadband light sources, such as ultrafast lasers, wavelength-swept lasers, super-luminescent LEDs, and super-continuum sources, have enabled versatile optical innovations, which opens up new possibilities to achieve fast-speed, large-volume, high-resolution, and high-dimensional optical measurements with unique capabilities. Herein, the main scope of this Research Topic is to bring together interesting novel optical measurement and imaging t...

Novel Optical Measurement and Imaging Technologies using Broadband Light Sources – Special Issue in Frontiers in Physics Journal

Optical measurement and imaging have been key fields in scientific and technological advancements. Historically, from the development of theories of quantum mechanics and relativity, to the discovery of DNA structure and astronomical events, optical measurement and imaging technologies, such as Michelson interferometer, large-scale space telescopes, high-resolution microscopy and crystallography, played critical roles in identifying key signals, structures, and interactions between light field and various types of materials.  Recently, broadband light sources, such as ultrafast lasers, wavelength-swept lasers, super-luminescent LEDs, and super-continuum sources, have enabled versatile optical innovations, which opens up new possibilities to achieve fast-speed, large-volume, high-resolution, and high-dimensional optical measurements with unique capabilities.  Herein, the main scope of this Research Topic is to bring together interesting novel optical measurement a...

University of Alabama at Birmingham Receives NIH Grant for Development of a supercontinuum laser source interferometer with sub-micron resolution to understand tear film structure and function in dry eye disease

University of Alabama at Birmingham Received a 2022 NIH Grant for $108,284 for Development of a supercontinuum laser source interferometer with sub-micron resolution to understand tear film structure and function in dry eye disease. The principal investigator is Yuqiang Bai. Below is a summary of the proposed work. In humans, the precorneal tear film (PCTF) is a thin layer (~3-5 µm) of a complex biological fluid coating the ocular surface, that serves to nourish and protect the ocular surface and provide a smooth refractive optical surface for vision. In dry eye disease, the PCTF becomes thinner, and destabilizes (evaporates) rapidly leading to hyperosmolarity, inflammation, and ocular surface desiccation. More than 30 million people in the United States are impacted by dry eye disease and the economic burden to society is estimated to be over $50 billion. Dry eye disease continues to be a challenge to diagnose, monitor, and treat because as many dry eye tests are conducted in...

EXALOS presents new combined-SLED modules and groundbreaking 488nm Laser Diodes and SLEDs at Photonics West in San Francisco

EXALOS’s new combined-SLED modules are high-performance, ultra-broadband, fiber-coupled light sources based on superluminescent light emitting diodes (SLEDs). Using an automated, high-precision alignment robot, the output beams of the individual SLEDs are combined using micro-optical lenses and free-space optics to a single, highly polarized output beam that is coupled into a single-mode or polarization-maintaining output fiber. Standard combi-SLEDs are available in the near-infrared, for wavelengths ranging from 750nm to 1600nm, or in the visible range with wavelengths from 650nm to 405nm. The combi-SLED products are highly customizable and meet highest performance and reliability demands. Photo of open RGB SLED module For the first time, a combination of up to four SLEDs are now integrated into a standard 14-pin butterfly package, achieving, for example, an ultra-broadband output spectrum with a 3dB bandwidth of 165nm at a center wavelength of 830nm, which translates into a ...

Low pump power coherent supercontinuum generation in heavy metal oxide solid-core photonic crystal fibers infiltrated with carbon tetrachloride covering 930–2500 nm

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All-normal dispersion supercontinuum (ANDi SC) generation in a lead-bismuth-gallate glass solid-core photonic crystal fiber (PCF) with cladding air-holes infiltrated with carbon tetrachloride (CCl 4 ) is experimentally investigated and numerically verified. The liquid infiltration results in additional degrees of freedom that are complimentary to conventional dispersion engineering techniques and that allow the design of soft-glass ANDi fibers with an exceptionally flat near-zero dispersion profile. The unique combination of high nonlinearity and low normal dispersion enables the generation of a coherent, low-noise SC covering 0.93–2.5 µm requiring only 12.5 kW of pump peak power delivered by a standard ultrafast erbium-fiber laser with 100 MHz pulse repetition rate (PRR). This is a much lower peak power level than has been previously required for the generation of ANDi SC with bandwidths exceeding one octave in silica- or soft-glass fibers. Our results show that liquid-...

Flattening the curve: Nano-film enhanced supercontinuum edition

Providing light with tailored properties through ultrafast supercontinuum generation represents an active field of nonlinear science research. A German-Australian research collaboration has presented a new concept that includes a longitudinally varying thickness nano-films in microstructured exposed core fibers. This offers low input energy, broadband and spectrally flattened spectra in the near infrared with high pulse-to-pulse stability, establishing a novel class of light sources for fields such as biophotonics, medical diagnostics, environmental sciences, or metrology. ( Read Full Article )

Millimeter-scale chip-based supercontinuum generation

In optics, when a collection of nonlinear processes act together on a pump beam, the resulting spectral broadening of the original pump beam gives rise to a supercontinuum . Supercontinuum sources for optical coherence tomography are of great interest since they provide a broad bandwidth for high resolution and high-power imaging sensitivity. For commercial fiber-based supercontinuum systems, researchers use high pump powers to generate a broad bandwidth and customized optical filters to modulate the spectra. In a new report now published on Science Advances , Xingchen Ji and a research team in electrical engineering, biomedical engineering and applied physics at the Columbia University, New York, U.S., introduced a supercontinuum platform based on a 1 mm 2 silicon nitride photonic chip for optical coherence tomography (OCT). The researchers directly pumped and efficiently generated a supercontinuum near 1300 nm and used the setup to image biological tissues and show the strong imag...

Millimeter-scale chip–based supercontinuum generation for optical coherence tomography

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Supercontinuum sources for optical coherence tomography (OCT) have raised great interest as they provide broad bandwidth to enable high resolution and high power to improve imaging sensitivity. Commercial fiber-based supercontinuum systems require high pump powers to generate broad bandwidth and customized optical filters to shape/attenuate the spectra. They also have limited sensitivity and depth performance. We introduce a supercontinuum platform based on a 1-mm 2 Si 3 N 4 photonic chip for OCT. We directly pump and efficiently generate supercontinuum near 1300 nm without any postfiltering. With a 25-pJ pump pulse, we generate a broadband spectrum with a flat 3-dB bandwidth of 105 nm. Integrating the chip into a spectral domain OCT system, we achieve 105-dB sensitivity and 1.81-mm 6-dB sensitivity roll-off with 300-μW optical power on sample. We image breast tissue to demonstrate strong imaging performance. Our chip will pave the way toward portable OCT and incorporating integr...

Microresonator-frequency-comb-based platform for clinical high-resolution optical coherence tomography

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A method of providing optical coherence tomography (OCT) imaging may comprise using an on-chip frequency comb source interfaced with an OCT system by a circulator as an imaging source and reconstructing OCT images from resulting spectral data from target tissue illuminated by the imaging source. ( Read Full Article )

White Paper on Superluminscent Diodes by Anritsu

Sensing systems using optical fibers as well as spectroscopic techniques using light absorption in the near-infrared domain of organic molecules are making remarkable advances and the need for light sources for even higher-performance sensing is accelerating. In these circumstances, the Super Luminescent Diode (SLD) is being adopted as a light source for optical-fiber sensing applications due to its broad optical spectrum with an output power matching LDs and low coherence, while featuring excellent optical fiber coupling efficiency. To see white paper click HERE.

Shot-noise limited, supercontinuum-based optical coherence tomography

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We present the first demonstration of shot-noise limited supercontinuum-based spectral domain optical coherence tomography (SD-OCT) with an axial resolution of 5.9 μm at a center wavelength of 1370 nm. Current supercontinuum-based SD-OCT systems cannot be operated in the shot-noise limited detection regime because of severe pulse-to-pulse relative intensity noise of the supercontinuum source. To overcome this disadvantage, we have developed a low-noise supercontinuum source based on an all-normal dispersion (ANDi) fiber, pumped by a femtosecond laser. The noise performance of our 90 MHz ANDi fiber-based supercontinuum source is compared to that of two commercial sources operating at 80 and 320 MHz repetition rate. We show that the low-noise of the ANDi fiber-based supercontinuum source improves the OCT images significantly in terms of both higher contrast, better sensitivity, and improved penetration. From SD-OCT imaging of skin, retina, and multilayer stacks we conclude that sup...

Optical coherence hyperspectral microscopy with a single supercontinuum light source

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In the paper, we have developed an optical coherence hyperspectral microscopy with a single supercontinuum light source. The microscopy consists of optical coherence tomography (OCT) and hyperspectral imaging (HSI), which can visualize the structural and functional characteristics of biological tissues. The 500-700 nm band is selected for HSI and OCT imaging, where HSI enables imaging of oxygen saturation and hemoglobin (Hb) content, while OCT acquires structural characteristics to assess the morphology of biological tissues. The system performance of the optical coherence hyperspectral microscopy is verified by normal mice ears, and the practical applications of the microscopy is further performed in 4 T1 and inflammation Balb/c mice ears in vivo. The experimental results demonstrate that the microscopy has potential to provide complementary information for clinical applications. This article is protected by copyright. All rights reserved. ( Read Full Article )

Soliton microcomb based spectral domain optical coherence tomography

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Spectral domain optical coherence tomography (OCT) is a widely employed, minimally invasive bio-medical imaging technique, which requires a broadband light source, typically implemented by super-luminescent diodes. Recent advances in soliton based photonic integrated frequency combs (soliton microcombs) have enabled the development of low-noise, broadband chipscale frequency comb sources, whose potential for OCT imaging has not yet been unexplored. Here, we explore the use of dissipative Kerr soliton microcombs in spectral domain OCT and show that, by using photonic chipscale Si 3 N 4 resonators in conjunction with 1300 nm pump lasers, spectral bandwidths exceeding those of commercial OCT sources are possible. We characterized the exceptional noise properties of our source (in comparison to conventional OCT sources) and demonstrate that the soliton states in microresonators exhibit a residual intensity noise floor at high offset frequencies that is ca. 3 dB lower than a traditional ...

Nanoplus Launches Superluminescent Eiodes (SLD) in the Spectral Band from 760 nm to 2900 nm

nanoplus, a German manufacturer (sales@nanoplus.us), launches superluminescent diodes (SLD) in the spectral band from 760 nm to 2900 nm. The devices complement nanoplus well-known product portfolio of Distributed Feedback Lasers (DFB). They used their expertise as technology leader for DFB lasers to create broadband light sources in the near infrared. For more than 20 years, we have been manufacturing DFB and Fabry Perot (FP) lasers with excellent performance - the same technology is used for our SLDs. The new SLD devices combine the proven beam quality of nanoplus DFB lasers with the large spectrum of LEDs.  The figures show the typical spectrum and power-voltage-current curves of a 2170 nm SLD. nanoplus SLDs are available in various free space and fiber coupled packages with or without TEC cooling. For smooth installation select our plug and play module. It consists of an SLD mounted on a TO66 header, which is built in a heatsink with collimation optics. nanopl...

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  • Local polarization properties extraction using single incident state, single-mode-fiber-based spectral domain polarization-sensitive optical coherence tomography
  • Physiology-guided vs Angiography-guided Non-culprit Lesion Complete Revascularization for Acute MI & Multivessel Disease (COMPLETE-2)