We demonstrate a tunable filter consisting of a subwavelength resonant grating filter cladded by a liquid crystal cell. The resonant wavelength of the grating filter is tuned by electrically varying the refractive index of the liquid crystal. A tuning range of around 20 nm has been achieved.

We report a new approach, termed "growth by nanopatterned host-medicated catalyst" (NHC growth), to solve nonuniformities of Si nanowires (NWs) grown on amorphous substrates. Rather than pure metal catalyst, the NHC uses a mixture of metal catalyst with the material to be grown (i.e., Si), nanopatterns them into desired locations and anneals them. The Si host ensures one catalyst-dot per-growth-site, prevents catalyst-dot break-up, and crystallizes catalyst-dot (hence orientating NWs). The growth results straight silicon NWs on SiO2 with uniform length and diameter (4% deviation), predetermined locations, preferred orientation, one-wire per-growth-site, and high density; all are 10-100 times better than conventional growth.

Background Colorectal cancer often presents with obstruction needing urgent, potentially life-saving decompression. The comparative efficacy and safety of endoluminal stenting versus emergency surgery as initial treatment for such patients is uncertain. Methods Patients with left-sided colonic obstruction and radiological features of carcinoma were randomized to endoluminal stenting using a combined endoscopic/fluoroscopic technique followed by elective surgery 1–4 weeks later, or surgical decompression with or without tumour resection. Treatment allocation was via a central randomization service using a minimization procedure stratified by curative intent, primary tumour site, and severity score (Acute Physiology And Chronic Health Evaluation). Co-primary outcome measures were duration of hospital stay and 30-day mortality. Secondary outcomes were stoma formation, stenting completion and complication rates, perioperative morbidity, 6-month survival, 3-year recurrence, resource use, adherence to chemotherapy, and quality of life. Analyses were undertaken by intention to treat. Results Between 23 April 2009 and 22 December 2014, 245 patients from 39 hospitals were randomized. Stenting was attempted in 119 of 123 allocated patients (96.7 per cent), achieving relief of obstruction in 98 of 119 (82.4 per cent). For the 89 per cent treated with curative intent, there were no significant differences in 30-day postoperative mortality (3.6 per cent (4 of 110) versus 5.6 per cent (6 of 107); P = 0.48), or duration of hospital stay (median 19 (i.q.r. 11–34) versus 18 (10–28) days; P = 0.94) between stenting followed by delayed elective surgery and emergency surgery. Among patients undergoing potentially curative treatment, stoma formation occurred less frequently in those allocated to stenting than those allocated to immediate surgery (47 of 99 (47.5 per cent) versus 72 of 106 (67.9 per cent); P = 0.003). There were no significant differences in perioperative morbidity, critical care use, quality of life, 3-year recurrence or mortality between treatment groups. Conclusion Stenting as a bridge to surgery reduces stoma formation without detrimental effects. Registration number: ISRCTN13846816 (http://www.controlled-trials.com).

We use a novel technique, self-perfection by liquefaction (SPEL), to smooth the rough sidewalls of Si waveguides. An XeCl excimer laser with 308 nm wavelength and 20 ns pulse duration is used to selectively melt the surface layer of the waveguide. This molten layer flows under surface tension and this results in smooth sidewalls upon resolidification. Our experimental results show that this technique reduces the average sidewall roughness (1sigma) from 13 to 3 nm. Our calculations show that the waveguide transmission loss due to sidewall roughness in these waveguides would be reduced from 53 to 3 dB cm(-1), an improvement with light transmission five orders of magnitude greater. Due to a low viscosity of molten Si (below water), SPEL can be achieved on a Si surface within approximately 100 ns. This short time, together with SPEL's material selectivity, makes it possible to repair defective components on a chip without damaging surrounding components and materials, making SPEL a promising candidate for defect repair in integrated optics and nanophotonics.

The authors present a technique for the replication of molds for nanoimprint lithography (NIL) without solvents or etching. A thin hard amorphous silicon film is deposited onto imprinted or self-assembled polymer nanostructures by room-temperature conformal plasma-enhanced chemical vapor deposition. After attachment to another substrate and separation from the polymer original, the thin hard film forms a NIL mold that is the inverse of the polymer original. Using this technology, the authors demonstrate the replication of a 200nm pitch grating mold and sub-50-nm features over wafer-scale areas without introducing additional line edge roughness associated with conventional replication methods.