S. Mar

Measurement of Stark broadening and shift of singly ionized Ar lines

A very extensive compilation of Stark widths and shifts for more than 125 Ar II visible spectral lines is presented in this work. These atomic parameters have been measured in a pulsed discharge lamp by using different mixtures of pure argon or argon and helium. The electron density, which typically ranges from 0.2 to has been determined interferometrically and, in the case of pure argon plasmas, also spectroscopically from -Stark broadening. The Ar II excitation temperature (15 000-31 000 K) has been determined by Boltzmann-plot techniques from the intensity of Ar II lines. A detailed description of all the relevant points in this kind of measurement is given. Comparisons with most of the data published about this topic for Ar II are also included.

Measurement of Stark broadening and shift parameters of several Ar I lines

This work reports Stark shifts and widths of 15 Ar I lines measured in a pulsed arc. Plasma parameters, electron density and temperature, range in this experiment from 0.25 to and from 13 500 to 26 500 K, respectively. The former has been measured interferometrically at a single wavelength and spectroscopically from the -Stark broadening. The latter has been measured from the Boltzmann plot of Ar II lines and from the ratio of Ar II and Ar I line intensities. Comparisons with most of the data published to date about this topic in Ar I are also included.

Calibration of the Stark-broadening parameters of two He I lines with forbidden components

Measurements of the Stark-broadening parameters of two \HeI lines with forbidden components, have been done in a pulsed arc plasma. Electron density, ranging from 1.50×1022 to 1.45×1023 m-3, is obtained by the interferometry of two wavelengths. Plasma temperature, determinated by Boltzmann plots of several \HeIlines, lies in the interval 16 000–25 000 K. A set of four geometrical profile parameters are obtained and compared with previous experimental and theoretical results. The empirical formulae proposed in this paper can be used in plasma diagnostics.

Transition probability measurement in an Ar II plasma

This work reports a collection of 200 Ar II transition probabilities of lines in the spectral region 360 - 750 nm for 16 lifetime values, all of them measured in an emission experiment. Relative intensity measurements have been made on a pulsed discharge lamp and the absolute values have been obtained by using data taken from the literature. The electron density, which ranges from 0.2 to in the plasma, has been determined simultaneously by interferometry and from -Stark broadening. The Ar II excitation temperature (15 000 - 27 000 K) has been calculated by a new method which also provides transition probabilities and plasma composition. The high number of measurements has allowed us to properly discuss the plasma equilibrium model. Comparisons have been made with the most recent experimental and theoretical data collections.

Stark widths of Xe II lines in a pulsed plasma

In this paper, we present a review of experimental work on Stark broadening of singly ionized xenon lines. Eighty lines, from close UV to the red region of the spectrum, have been studied. Stark halfwidths were compared with experimental data from the literature and modified semi-empirical calculations. A pulsed arc with 95% of helium and 5% xenon was used as a plasma source for this study. Measured electron densities Ne and temperatures T were in the ranges of 0.2–1.6 × 10 23 m −3 and 18 300–25 500 K, respectively.

Stark broadening and shift measurements of visible Si II lines

A set of experimental Stark width and shift parameters of visible singly ionized silicon spectral lines is reported in this paper. Measurements have been made on a pulsed plasma generated in a linear discharge lamp filled with a mixture of silane and helium. Electron density and temperature in this plasma range from 0.2 to 0.9 × 1023 m−3 and from 16 000 to 20 000 K respectively. Electron density has been simultaneously determined by two-wavelength interferometry and from Stark broadening of He I 501.6 nm, He I 728.1 nm and Hα lines. Temperature has been simultaneously determined from a Boltzmann plot of He I lines, from absolute emission of He I lines and from a Boltzmann plot of Si II lines. Dependences of measured Stark parameters on electron density and temperature have been investigated and the final results have been compared with most of the previous experimental data as well as with some theoretical models.

Experimental measurement of corneal haze after excimer laser keratectomy.

We developed a model of corneal haze following photorefractive keratectomy (PRK) in Iber Braun hens and studied optical properties. The animals underwent PRK for -9.0 diopters of myopia and were divided into groups based on treatment with different wound-healing modulators. At different time points postoperatively, we evaluated haze by slit-lamp microscopy. An experimental device was developed to measure transmittance spatial maps and forward scattering of He-Ne laser light in the excised corneas. Subjective and objective haze measures were compared for each group at the different times. Keratocyte densities were determined by optical microscopy and keratocyte sizes by electron microscopy. The agreement between experimental results and a simple numerical model of scattering suggests that increases in stromal keratocyte density after PRK might explain the degree of corneal haze.

Measurement of Stark broadening and shift of visible N II lines

This work reports information about Stark broadening and shift parameters of a very extensive collection of visible singly ionized nitrogen lines. All of them were measured in a linear discharge lamp from a mixture of nitrogen and helium. Electron density and temperature range in this experiment from 0.2 to 1.1 × 1023 m-3 and from 17 000 to 29 000 K, respectively. The first one has been simultaneously determined from two-wavelength interferometry and from the Stark broadening of He I 471.3 nm, the second from a Boltzmann plot of N II lines and from N II/N I intensity ratios. Dependences of these Stark parameters with temperature and electron density have been investigated and the final results have been compared with most of the previous experimental data as well as with two theoretical models. All relevant details relative to this experiment are given in the paper.

Temporal retinal sensitivity in mesopic adaptation

Citation information: Matesanz BM, Issolio L, Arranz I, de la Rosa C, Menéndez JA, Mar S & Aparicio JA. Temporal retinal sensitivity in mesopic adaptation. Ophthalmic Physiol Opt 2011, 31, 615–624. doi: 10.1111/j.1475‐1313.2011.00859.x

Design of aberration-balanced high-efficiency focusing holographic gratings

A volume and phase focusing holographic grating to be used as the principal element of a high-resolution spectrometer has been designed with the aid of a computer. A two-step method was used; first designs were obtained with an aberration-balancing technique, and, in the second step, these early designs are optimized by a ray tracing procedure to obtain aberration-balanced high-efficiency holograms that can be used in highresolution spectroscopy.