Bandwidth and conversion-efficiency analysis of Kerr soliton combs in dual-pumped resonators with anomalous dispersion

Kerr frequency combs generated in high-Q microresonators offer an immense potential in many applications, and predicting and quantifying their behavior, performance and stability is key to systematic device design. Based on an extension of the Lugiato-Lefever equation we investigate in this paper the perspectives of changing the pump scheme from the well-understood monochromatic pump to a dual-tone configuration simultaneously pumping two modes. For the case of anomalous dispersion we give a detailed study of the optimal choices of detuning offsets and division of total pump power between the two modes in order to optimize single-soliton comb states with respect to performance metrics like power conversion efficiency and bandwidth. Our approach allows also to quantify the performance metrics of the optimal single-soliton comb states and determine their trends over a wide range of technically relevant parameters

Global continua of solutions to the Lugiato–Lefever model for frequency combs obtained by two-mode pumping

We consider Kerr frequency combs in a dual-pumped microresonator as time-periodic and spatially $2\pi$-periodic traveling wave solutions of a variant of the Lugiato-Lefever equation, which is a damped, detuned and driven nonlinear Schrödinger equation given by $ia_\tau = (\zeta − i ) a − da_{xx} − |a|^2 a + i f_0 + i f_1\text{e}^{i( k_1 x−ν_1 \tau)}$. The main new feature of the problem is the specific form of the source term $f_0 + f_1 \text{e}^{i(k_1 x− ν_1 \tau )}$ which describes the simultaneous pumping of two different modes with mode indices $k_0 = 0$ and $k_1\in\mathbb{N}$. We prove existence and uniqueness theorems for these traveling waves based on a-priori bounds and fixed point theorems. Moreover, by using the implicit function theorem and bifurcation theory, we show how non-degenerate solutions from the 1-mode case, i.e. $f_1 = 0$, can be continued into the range $f_1\ne 0$. Our analytical findings apply both for anomalous $(d > 0)$ and normal $(d < 0)$ dispersion, and they are illustrated by numerical simulations

Ultra-High-Resolution Optical Coherence Tomographic Findings in Commotio Retinae

Commotio retinae is a self-limited opacification of the retina secondary to direct blunt ocular trauma. Histologic studies of monkeys and humans relate this clinical observation to damaged photoreceptor outer segments and receptor cell bodies.[superscript 1 - 3] Reports using time-domain optical coherence tomography (OCT) and spectral-domain OCT support the involvement of the photoreceptor layer, but these techniques lack the resolution necessary to confirm results of histologic analysis.[superscript 4 - 6] Prototype high-speed ultra–high-resolution OCT (hs-UHR-OCT) images demonstrate these anatomical changes in a patient with acute commotio retinae.National Institutes of Health (U.S.) (Contract Number RO1-EY11289-23)National Institutes of Health (U.S.) (Contract Number R01-EY13178-07)United States. Air Force Office of Scientific Research (Grant Number FA9550-07-1-0101)United States. Air Force Office of Scientific Research (Grant Number FA9550-07-1-0014

Potential of rust-resistant arabica coffee cultivars for specialty coffee production

Rust is the main disease affecting Coffea arabica, the most economically important coffee species. The objective of this study was to analyze C. arabica cultivars with different levels of rust resistance, including bean size, raw bean appearance, final sensory scores (FSS), and aroma and taste nuances of the coffee cup. The experiment was designed in randomized blocks (RBD) with three replications and 20 treatments (cultivars), totaling 60 experimental plots. The rust-susceptible cultivars IPR 100, Rubi MG 1192, and Topázio MG 1190 were compared with 17 rust-resistant cultivars. Cultivars IPR 103, MGS Aranãs, and Saíra II presented the highest percentages of high sieves, highest scores of raw bean appearance, and low percentages of mocha-type beans. All cultivars had FSS above 82 and were classified as specialty coffees. The cultivars with the highest FSS (Arara and Catiguá MG2) showed a greater diversity of coffee cup aroma and flavor nuances. Rust-resistant Arabica coffee cultivars are promising for the physical quality of beans and have potential for the specialty coffee market

Effect of intravitreal aflibercept on recalcitrant diabetic macular edema

Abstract Background Despite anti-VEGF therapy, some patients develop chronic diabetic macular edema. The objective of this study was to evaluate anatomic and visual outcomes of switching patients with chronic DME from intravitreal bevacizumab or ranibizumab to intravitreal aflibercept injection. Methods In this retrospective observational case series, 11 eyes with recalcitrant diabetic macular edema (DME) were evaluated 6 months prior to and 6 months following initial intravitreal aflibercept injection (IAI). Recalcitrant DME was defined as having a thickened retina (≥350 μm) on spectral domain optical coherence tomography (SD-OCT) with persistent cystic changes (less than a 15% reduction in central retinal thickness) over 6 months prior to intravitreal aflibercept switch despite aggressive treatment for DME during this time. Results One hundred and forty-seven patients in total were treated with IAI during this time, and of these, 31 patients were treated with IAI for DME. 18 eyes had less than 4 treatments within the 6 months prior to switch to IAI, 6 patients had a central retinal thickness (CRT) on SD-OCT of less than 350 μm at time of switch to IAI, and 2 patients had a greater than 15% decline in CRT on SD-OCT over the 6 months prior to switch to IAI. A total of 11 patients were included in the study. Over the 6 months prior to switch, the mean change in central retinal thickness was +18.6% and over the 6 months following switch to aflibercept the mean change in central retinal thickness was −27.1%. Switching to a regimen of at least 3 intravitreal aflibercept injections over 6 months resulted in some anatomic improvement and improvement or stabilization of Snellen visual acuity in all eligible patients. Conclusions In patients with recalcitrant diabetic macular edema, switching to intravitreal aflibercept resulted in improved a 25% or more decrease in central retinal thickness in 81% (9/11) patients at 6-month follow-up. Sixty-three percent (7/11) had improvement in Snellen visual acuity after switching to intravitreal aflibercept injection, suggesting some reversibility of functional damage

Intravitreal bevacizumab (Avastin) as treatment for subfoveal choroidal neovascularisation secondary to pathological myopia

OBJECTIVE: To evaluate the safety and efficacy of intravitreal bevacizumab (Avastin) as treatment for subfoveal choroidal neovascularisation (CNV) due to pathological myopia. METHODS: Consecutive series of primary or recurrent subfoveal CNV secondary to myopia treated with intravitreal bevacizumab 1.25 mg between August 2005 and January 2006 at the New England Eye Center, Boston, Massachusetts, USA, were reviewed retrospectively. Data from clinical examination, fundus photography, fluorescein angiography, optical coherence tomography and visual acuity were collected. RESULTS: There were 11 eyes of 9 patients. 5 of 11 eyes had been treated previously with photodynamic therapy. Pre‐injection visual acuity measured 20/50 to 20/100 in 6 eyes and 20/200 or worse in 5 eyes. After a mean follow‐up of 153 (range 35–224) days, post‐injection visual acuity measured 20/20 to 20/40 in 7 eyes, 20/50 to 20/100 in 1 eye and 20/200 or worse in 3 eyes. Three eyes received two bevacizumab injections and eight eyes received one injection. Visual acuity improved by a mean of +3.5 (range −1 to +8 lines) lines, and 8 of 11 eyes achieved 20/50 or better at the last follow‐up. Central foveal thickness improved from 340 (range 253–664) μm to 234 (range 142–308) μm, representing an average reduction of 103 (range +4 to −356) μm. No injection complications or drug‐related side effects were observed. CONCLUSIONS: In this small series of eyes with limited follow‐up, intravitreal bevacizumab seems to be safe and potentially efficacious in eyes with subfoveal CNV secondary to pathological myopia

Transpupillary thermotherapy of occult subfoveal choroidal neovascularization in patients with age-related macular degeneration

To evaluate the efficacy of transpupillary thermotherapy for the treatment of occult subfoveal choroidal neovascularization (CNV) in patients with age-related macular degeneration. A retrospective, noncomparative case series. Sixteen eyes of 15 consecutive patients who presented with occult subfoveal choroidal neovascularization secondary to age-related macular degeneration. After informed consent was obtained, 16 eyes of 15 patients were treated with transpupillary thermotherapy. All patients underwent pretreatment fluorescein angiography and were deemed untreatable by the Macular Photocoagulation Study standard. Transpupillary thermotherapy was delivered using a diode laser at 810 nm. A variable spot size of 1.2 mm, 2.0 mm, or 3.0 mm was used depending on the size of CNV. The diode laser was delivered through a contact lens, and treatment was initiated in one spot for 60 seconds’ duration at a power range between 360 and 1000 mW. The end point was an area of no visible color change to a light-gray appearance. In all eyes, outcome was assessed by Snellen chart visual acuity and clinical examination. In 10 of 16 eyes, preoperative and postoperative fluorescein angiography and optical coherence tomography were available. In the remaining 6 of 16 eyes, exudation was measured by postoperative clinical examination alone. Three eyes (19%) showed a two-or-more-line improvement in visual acuity over a period of 6 to 25 months. Mean follow-up was 13 months. Visual acuity remained stable (no change or one-line improvement) in nine treated eyes (56%). The remaining four eyes (25%) showed a decline (equal to one-line worsening or greater) in visual acuity. Fifteen eyes (94%) demonstrated decreased exudation on fluorescein angiography, optical coherence tomography, and/or clinical examination. Transpupillary thermotherapy shows no deleterious side effects in treating occult subfoveal choroidal neovascularization. A randomized, prospective study is necessary to evaluate treatment efficacy

Early Evolution of the Vitreomacular Interface and Clinical Efficacy After Ocriplasmin Injection for Symptomatic Vitreomacular Adhesion

BACKGROUND AND OBJECTIVE: To determine early evolution of the vitreomacular interface and clinical efficacy and safety profile after ocriplasmin treatment. PATIENTS AND METHODS: Retrospective, multicenter, observational case series. Patients with vitreomacular adhesion (VMA) confirmed on optical coherence tomography (OCT) received a single intravitreal ocriplasmin injection. Changes in the vitreomacular interface were evaluated by spectral-domain OCT. Adverse events were monitored at all visits. RESULTS: Of 22 patients treated with ocriplasmin, 14 (64%) had VMA resolution, with six (43%) achieving VMA release within the first week. Eight patients (36%) showed improvement in visual acuity (VA) of at least two Snellen lines. Rate of VMA resolution was 79% for VA less than 20/40 and 38% for VA of 20/40 or greater. Safety findings include changes in the ellipsoid layer (n = 3) and transient increases in subretinal fluid (n = 6). CONCLUSION: Ocriplasmin was effective for VMA resolution, with a rapid onset of action. Patients with worse baseline VA showed a higher VMA resolution rate.status: publishe