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Fabricating first order gratings for laterally coupled distributed feedback (LC-DFB) lasers can be challenging due to aspect ratio dependent etching. Developments in focused ion beam (FIB) processing and source technology introduce the potential to mill grating structures directly into a ridge waveguide (RWG) laser structure without the requirement for electron beam lithography and inductively coupled plasma etching. In this work, we investigate the suitability of using bismuth and gold FIBs to mill Bragg gratings for DFB laser diodes directly into as well as adjacent to InP RWG laser structures. We explore the milling strategy on the profile of the fabricated grating structures. We observe that the single pixel line scanning routine is favorable when milling directly onto an RWG and using a concentric scanning method is better when milling the grating structures adjacent to the RWG. We conclude that milling off-ridge is more promising using this technique, as gratings with sidewall angles of 18 ° have been milled to a depth of over 350 nm. Based on modeling, a grating milled adjacent to the ridge with a dose of 60 000 μ C / cm 2 would provide a coupling strength of 73 cm − 1 . Such values would be suitable for DFB laser devices with cavity lengths as low as 200 μ m. [ABSTRACT FROM AUTHOR]

Abstract: Alpha-7 nicotinic acetylcholine receptor (α7 nAChR) agonists attenuate pain and inflammation in preclinical models. This study tested whether systemic delivery of an α7 nAChR agonist attenuates neuropathic pain and associated immune-mediated pro-inflammation. Hind paw response thresholds to mechanical stimuli in male Sprague Dawley rats were assessed before and after sciatic chronic constriction injury (CCI) or sham surgery. Osmotic mini-pumps containing TC-7020, an α7 nAChR selective agonist, were implanted 10 to 14 days after surgery. TC-7020 (1, 3, and 10 mg/kg/d; s.c.) significantly attenuated CCI-induced allodynia, which lasted through 2 weeks of test compound administration. Spinal cords were collected after 2 weeks and processed for microglial and astrocyte activation markers within the ipsilateral L4-L6 dorsal horn. In addition, ipsilateral L4-5 dorsal root ganglia (DRGs) were processed for neuronal injury and satellite cell activation markers. CCI-induced central glial cell activation markers were not suppressed by TC-7020, even though TC-7020 is mildly blood-brain barrier permeable. However, TC-7020 downregulated the integrated density of activation transcription factor 3 (ATF3) but not the number of ATF positive cells. TC-7020 also downregulated phosphorylated extracellular signal kinase (p-ERK) and satellite cell activation in the CCI-affected DRGs. Therefore, systemic α7 nAChR agonist may be effective in treating neuropathic pain via reducing neuronal injury and immune cells activation occurring in the periphery. Perspective: These studies demonstrated that TC-7020, an alpha7 nicotinic acetylcholine receptor agonist with partial blood-brain barrier permeability, reversed neuropathic pain in rats, likely via attenuation of inflammation in the DRG and/or the site of sciatic injury. [Copyright &y& Elsevier]

An influence of the specific kinetic energy E sp and nuclearity n of Bi n + (n = 1–4) projectiles on the sputter yield of Si was studied by means of the volume loss method. It was found that the specific sputter yield Y sp exhibited non-additive increase with an increasing of n and E sp values. As a non-additivity k -factor, the slope of the straight line approximating Y sp (n) dependences at the same specific energy was proposed to use. For Bi n + (n = 1–4) projectiles at E sp = 10 keV at−1 the k -factor was equal to 0.41 ± 0.08. In addition, it was ascertained that the efficiency of energy transfer from projectiles to target atoms increased with an increase in the projectile nuclearity, e.g., it was 2.8 times greater for Bi 3 + bombarding ions as compared with Bi+ ones. • Si sputtering by Bi n + (n = 1–4) projectiles. • Volume loss method for sputter yield measurements. • Non-additive sputtering vs specific kinetic energy and nuclearity of projectiles. [ABSTRACT FROM AUTHOR]

A carbon-cerium alloy liquid metal ion source (LMIS) with unintentional aluminum content is presented for generating focused ion beams of carbon ions, as well as ionized clusters with sizes of 2, 4, and 8 atoms. Emission-current-dependent measurements were carried out for the mass spectra and energy spread of all species, but focused on the carbon monomer ions and clusters. The full width at half maximum of the energy distribution was determined to be 6.5 eV for the monomer carbon ion and 14 eV for the light clusters at an emission current of 5 μA. The source showed good beam performance when used with a mass-separated focused ion beam column. Applications to graphene structures, organic matter, and other carbon-containing materials are promising tasks for the new carbon-containing alloy LMIS. [ABSTRACT FROM AUTHOR]

We present an idea to control the progress during focused ion beam milling of cantilevers. Since the monitoring options given by the focused ion beam machine did not satisfy our needs for complete control of the milling process, we decided to measure the current behind the target. A simple current to voltage converter and the electric setup are presented in this Note. [ABSTRACT FROM AUTHOR]

The formation of Agn clusters and Agn+ cluster ions under bombardment of a silver surface with SF5+ and Xe+ projectile ions was investigated experimentally. In order to obtain information about the relative abundance of clusters among the flux of sputtered particles independent of their charge state, mass spectra of both secondary ions and sputtered neutral particles were recorded. The neutral species were post-ionized prior to mass analysis by means of photo-ionization using an intense UV laser at a wavelength of 193 nm. It is found that measured Agn+ signals increase significantly if SF5+ projectiles are used instead of rare gas (Ar+ or Xe+) ions of the same kinetic impact energy. The signals of neutral Ag atoms and Agn clusters, on the other hand, exhibit only a relatively small increase, thus indicating that the enhancement observed for the secondary ions is predominantly caused by an increased ionization probability of sputtered particles under SF5+ bombardment rather than by enhanced partial sputtering yields. While the transition from Ar+ to Xe+ projectiles leads to a drastic increase of the relative abundance of larger clusters in the spectrum, practically no such effect can be detected for the transition from Ar+ to SF5+. This finding shows that the use of polyatomic SF5 projectiles does not lead to a higher efficiency in producing sputtered clusters. [Copyright &y& Elsevier]