Juan A. Aparicio

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.

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

Quantitative and functional influence of surround luminance on the letter contrast sensitivity function.

Aim:  To determine the influence of surround luminance on the letter contrast sensitivity function.

Influence of surround illumination on pupil size and contrast sensitivity

Lighting plays a major role in contrast sensitivity (CS) measurements. Both the test and surround illumination influence the results although they are not usually considered in clinical practice. The effects of test luminance are well known, but the influence of surround luminance seems to be less investigated. This study aims to evaluate the differences in CS measured with two configurations of surround illumination typical of clinical practice; and to analyse the influence of the angular size of the target on pupil diameter for both surround luminances. An experimental arrangement was designed to measure CS with controlled illumination of both test and surround. An infrared pupillometer was also used to measure steady pupil size. A statistically significant increase of CS and a decrease of pupil size with higher surround illumination were found.

Experimental Stark Widths and Shifts of Several Ne I Spectral Lines

This work reports data of Stark widths and shifts of 37 Ne I lines that have been measured as functions of electron density and temperature in the ranges (0.07-1.85)×1023 m-3 and 13,900-20,700 K, respectively. A pulsed arc was used as a plasma source. The electron density was measured by single-wavelength interferometry using the 488.0 nm transition of an Argon ion laser and has also been determined from Hα Stark broadening. The plasma temperature has been determined from the Boltzmann plot of Ne I lines and estimated from the Saha law. Linear fits have been performed between Stark parameters and electron density, and possible dependencies on temperature have been checked. The measured parameters are compared with theoretical and experimental data taken from the literature.