27 research outputs found
Ultra-low-noise supercontinuum generation with a flat near-zero normal dispersion fiber
A pure silica photonic crystal fiber with a group velocity dispersion
() of 4 ps/km at 1.55 m and less than 7 ps/km from 1.32
m to the zero dispersion wavelength (ZDW) 1.80 m was designed and
fabricated. The dispersion of the fiber was measured experimentally and found
to agree with the fiber design, which also provides low loss below 1.83 m
due to eight outer rings with increased hole diameter. The fiber was pumped
with a 1.55 m, 125 fs laser and, at the maximum in-coupled peak power
(P) of 9 kW, a 1.341.82 m low-noise spectrum with a relative
intensity noise below 2.2\% was measured. The numerical modeling agreed very
well with the experiments and showed that P could be increased to 26 kW
before noise from solitons above the ZDW started to influence the spectrum by
pushing high-noise dispersive waves through the spectrum
Using a single supercontinuum source for visible multispectral photoacoustic microscopy and 1300 nm optical coherence tomography
We present a bimodal system driven by a supercontinuum source to perform photoacoustic-based spectral selective absorption measurements from 500 nm to 800 nm and structural optical coherence tomography imaging at 1300 nm. An energy of 5 to 40 nJ is achieved on sample within a 50 nm bandwidth in the visible range in the photoacoustic channel. Also, a few mW power is also achieved on the sample in the optical coherence tomography channel
Polarization extinction ratio and polarization dependent intensity noise in long-pulse supercontinuum generation (Conference Presentation)
Real-time multimodal high resolution biomedical imaging instrument using supercontinuum optical sources
We present progress towards developing a multimodality imaging instrument, optical coherence tomography (OCT)/ photo-acoustic microscopy (PAM). By utilizing supercontinuum optical sources, that deliver wide spectral bandwidths and high energy densities, we devised a real-time imaging instrument which can be employed to image biological tissues. The OCT channel was devised to operate around 1300 nm. A custom built spectrometer ensures a constant axial resolution of 6 µm over an axial range of up to 1.5 mm. The PAM operates within the therapeutic window providing an axial resolution of 30 µm. The lateral resolution in both channels is 6 µm
High energy supercontinuum sources using tapered photonic crystal fibers for multispectral photoacoustic microscopy
We demonstrate a record bandwidth high energy supercontinuum source suitable for multispectral photoacoustic microscopy. The source has more than 150 nJ?10 nm bandwidth over a spectral range of 500 to 1600 nm. This performance is achieved using a carefully designed fiber taper with large-core input for improved power handling and small-core output that provides the desired spectral range of the supercontinuum source
Two octaves spanning photoacoustic microscopy
In this study, for the first time, a Photoacoustic Microscopy instrument driven by a single optical source operating over a wide spectral range (475–2400 nm), covering slightly more than two octaves is demonstrated. Xenopus laevis tadpoles were imaged in vivo using the whole spectral range of 2000 nm of a supercontinuum optical source, and a novel technique of mapping absorbers is also demonstrated, based on the supposition that only one chromophore contributes to the photoacoustic signal of each individual voxel in the 3D photoacoustic image. By using a narrow spectral window (of 25 nm bandwidth) within the broad spectrum of the supercontinuum source at a time, in vivo hyper-spectral Photoacoustic images of tadpoles are obtained. By post-processing pairs of images obtained using different spectral windows, maps of five endogenous contrast agents (hemoglobin, melanin, collagen, glucose and lipids) are produced