Hl 2000 fhsa

The completed Al pattern was visually evaluated under a high-resolution field emission scanning electron microscope (FESEM S-4800, Hitachi). The transmission spectra were checked for different polarizations through the launching of a halogen-lamp (HL-2000-FHSA, Ocean Optics) collimated beam, which was properly polarized through a calcite crystal polarizer (GTH 10M-A, Thorlabs), toward the prepared filter that had been mounted on a motorized rotation stage via a focusing lens. The optical output was captured by a spectrometer (Avaspec-3648, Avantes) via a multimode fiber. The images that are related to each pixel of the color filter were captured using a digital microscope (Leica DM6000 M).

A Hitachi H-7650 transmission electron microscope (TEM, Japan) with an accelerating voltage of 200 kV was utilized to obtain TEM images. X-Ray Photoelectron Spectroscopy (XPS) was performed on a Kratos AXIS Ultra spectrometer equipped with a monochromated Al Kα (hν = 1486.6 eV) X-ray source (Kratos Analytical, Manchester, UK). Nicolet Magna 750 FTIR Spectrometer and Nic-Plan FTIR Microscope (Nicolet, USA) with pure KBr as the background was applied to record Fourier transform infrared (FTIR) spectra (400–4000 cm⁻¹). The microgel samples for TEM, XPS and FTIR characterization were prepared using the procedure described below for generating AgNPs in the etalons with two modifications. First, to obtain sufficient sample for analysis we didn't wash the slide after microgel painting, which yielded a thick microgel layer for AgNP generation. Second, the etalon's top Au layer was not deposited on the microgels, which allowed for their easy removal from the surface while avoiding potential contamination. Reflectance measurements were conducted using a USB2000+ spectrophotometer, an HL-2000-FHSA tungsten light source, and an R400-7-VISNIR optical fiber reflectance probe, all from Ocean Optics (Dunedin, FL). The spectra were recorded using Ocean Optics Spectra Suite spectroscopy software over a wavelength range of 400–1000 nm.

The bespoke hybrid optical system combines bNIRS (developed in UCL, UK) for the monitoring oxCCO along with measures of cerebral oxygenation, and DCS for monitoring cerebral blood flow (BFI, blood flow index), custom-made by Hemophotonics, S.L. (Barcelona, Spain).
The bNIRS consists of a tungsten halogen lamp light source (HL-2000-FHSA, Ocean Optics), a 700-nm long pass filter, and a custom-made micro spectrometer (644–917 nm, cooled CCD, 1024 pixels, Wasatch Photonics). The DCS system consists of a 785 nm long coherence (>8 m) diode laser and a 4-channel photon-counting detector. To guide the light to the piglet, a multimode fibre (400 µm, 0.37 Numerical Aperture (NA)) is used for the DCS laser, and a fibre bundle of 2.5 mm (30 µm fibres, 0.55 NA) is used for the bNIRS halogen source. For the detection, a fibre bundle of four single-mode fibres (3.5 µm, 0.13 NA) is used to direct the light to the four detectors for the DCS, and to the bNIRS (2 mm bundle of 30 µm fibres, 0.55 NA). All the fibres were made by Fibreoptic Systems and were 3 m long. A custom 3D-printed probe holder was designed to attach the fibres on the head of the piglet, with a source-detector separation of 3 and 2 cm for the bNIRS and the DCS, respectively. We use computer-controlled shutters to time multiplex the two instruments, allowing fast sequential measurements from each modality.