ABSTRACT
We report a case wherein adrenal function remained preserved despite bilateral adrenal infarction, as evidenced by dual-energy computed tomography (DECT) iodine density images. The patient was a 37-year-old man with a history of antiphospholipid syndrome concomitant with systemic lupus erythematosus. The patient underwent contrast-enhanced DECT, which revealed bilateral adrenal infarction. Laboratory tests revealed preserved adrenal function. On the iodine density images, the infarcted and noninfarcted areas in the adrenal glands were visually different. The volume of the non-infarcted area was 8.9 mL, which was 41% of the total adrenal volume. DECT may be a useful complementary tool for assessing the preservation of adrenal function.
ABSTRACT
We demonstrated detection of birefringence singularity on the space-variant retarder with an inhomogeneous birefringence distribution by supercontinuum vector beam. The birefringence measurement by supercontinuum vector beam analysis provides kinematics of a singularity point on the space-variant retarder. We conducted numerical calculations and experiments for proof of principle. The calculated results were characterized by relative positions with (x0,y0) between the singularity point and the vector beam. In the experiments, we measured the retardance and the azimuthal angle from intensity profile on a single-shot image captured at wavelengths of λ=450, 550, and 650 nm. The retardances at λ=450nm and 550 nm were changed from Δ=112∘ to 131° and from Δ=120∘ to 152° when the x0 displacement of the space-variant retarder moved from 0 to 350 µm. The measured retardance corresponded with the calculated results in the function of the position of birefringence singularity.
ABSTRACT
We demonstrated a single-shot, multispectral birefringence mapping by use of a supercontinuum (SC) vector beam. The vector beam, which was generated by a pair of axially symmetric wave plates, leads to angular-variant polarization modulation to divide birefringence properties of a sample substrate into Fourier space. This strategy allows multispectral birefringence mapping from a single-shot image captured by a multispectral imaging detector. For SC vector beam analysis, we also compensated the retardance error of the axially symmetric wave plate in the superbroadband spectrum. Resolutions of retardance and azimuthal angle were 0.4° and 0.2°, respectively, and the spatial resolution was 60 µm. Those results are expected to provide us a single-shot, multispectral birefringence mapping with high spatial resolution as compared with using a scanning laser microscope. Our proposal has extendibility to develop high-speed, high-resolution birefringence imaging spectroscopy.
ABSTRACT
Although imaging techniques using soft X-rays (SXs) are being developed as the available photon flux increases because of the continuing development of synchrotron light sources, it will be necessary to downsize the pixel size of the SX camera to produce finer SX images. Application of the stimulated emission depletion (STED) method to a scintillator plate followed by use of this plate as a sensor is one promising method to reduce the pixel size of SX cameras. A STED phenomenon occurred in the luminescence of a Ce-doped Lu2SiO5 crystal (Ce:LSO) excited using ultraviolet (UV) light when the scintillator was irradiated with azimuthally polarized laser light in the photon energy range from 1.97 eV (630 nm) to 2.58 eV (480 nm). When the excitation light source changed to synchrotron radiation (SR) light with photon energy of 800 eV, the same STED phenomenon occurred. The spot size of the luminescence was reduced by the STED phenomenon and this spot size decreased as the STED laser's photon energy increased. The energy dependence of the Ce:LSO luminescence levels can be used to explain the change in the spot size at the luminescence point.
ABSTRACT
Our measurement of the soft X-ray emission of Mo plasmas produced by picosecond Nd:YAG lasers emitting on the fundamental (1064 nm, 150 ps) and second (532 nm, 130 ps) harmonics is presented. The contrast in intensity between spectral peaks and the intensity outside them is lower for the second harmonic produced plasmas probably due to the presence more intense satellite emission and higher optical thickness. The measured spectra are absolutely calibrated and the observed output photon flux was (7 - 9) × 1013 photons/sr in the water-window (2.3 - 4.4 nm) spectral range for a laser energy of 160 mJ independent of laser wavelength. However, in the short wavelength range 1.5 - 2 nm, the emission using the second harmonic is strongly enhanced and is even higher than for the maximum energy of 220 mJ of the fundamental wavelength, so despite inevitable energy losses, laser wavelength conversion may lead to emission enhancement in certain spectral ranges. This enhancement is attributed to higher absorption of short wavelength laser light and higher charge state generation in denser plasmas.
ABSTRACT
We demonstrate an inner surface profile measurement that has a smooth spatial distribution. A supercontinuum beam suppresses the speckle contrast to 22% and the standard deviation of the point cloud to 40%, compared to equivalent values obtained by use of a conventional green He-Ne laser at a wavelength of 543.5 nm. A compact probe for the inner surface profile measurements using the supercontinuum beam measures the depth removed by wear of a small hole in an automobile component. The radial spatial resolution was evaluated to be 2 µm, which was of the same order as the wavelength of the supercontinuum beam. The supercontinuum beam enables fivefold improvement of the radial spatial resolution compared to the monochromatic wavelength beam because of a reduction in speckle effects.
