Light guidance up to 6.5 µm in borosilicate soft glass hollow-core microstructured optical waveguides

Abstract

Limited operating bandwidth originated from strong absorption of glass materials in the infrared (IR) spectral region has hindered the potential applications of microstructured optical waveguide (MOW)-based sensors. Here, we demonstrate multimode waveguide regime up to 6.5 µm for the hollow-core (HC) MOWs drawn from borosilicate soft glass. Effective light guidance in central HC (diameter ∼240 µm) was observed from 0.4 to 6.5 µm despite high waveguide losses (0.4 and 1 dB/cm in near- and mid-IR, respectively). Additional optimization of the waveguide structure can potentially extend its operating range and decrease transmission losses, offering an attractive alternative to tellurite and chalcogenide-based fibers. Featuring the transparency in mid-IR, HC MOWs are promising candidates for the creation of MOW-based sensors for chemical and biomedical applications.

Optoacoustic Effect in a Hybrid Multilayered Membrane Deposited on a Hollow-Core Microstructured Optical Waveguide

“…The spectral properties of the HC-MOWs have been discussed previously. 32 Fabrication of a Hybrid Membrane. SWCNTs were synthesized by the aerosol (floating catalyst) chemical vapor deposition method described in detail elsewhere.…”

“…Presented probe based on HC-MOW has transmission bands spanning from 400 nm up to 2 μm (Figure 3) with potential transmission up to 6.5 μm. 32 Of specific interest is the near-infrared region, where the absorption peaks of lipid and collagen (1190 nm, 1210 nm, 1720 nm) overlap with the transmission band of OAP. This allows the probe to optoacoustically excite chromophores present in vulnerable lipid-rich plaques.…”

“…The HC-MOW geometry is detailed in Figure S1. The spectral properties of the HC-MOWs have been discussed previously …”

“…Hollow-core microstructured optical waveguides (HC-MOWs), despite having high optical losses, can support light transmission in the central core at wavelengths of 400 nm to 6.5 μm and can be promising in the development of NIR and MIR optoacoustic sensors. 32 Because most biomolecules of interest (proteins, lipids, carbohydrates) and water have narrow absorption peaks in the IR transmission range of the HC-MOWs, such waveguides can be used to deliver excitation light to the tissue of interest. Moreover, the MOW transmission spectrum has well-defined maximum and minimum bands, allowing selective filtering of undesirable vibrational peaks, for example, reducing the influence of strong absorption of water in the IR region.…”

Quantum entanglement and interference at 3 μm

“…Because of the better scattering resistance of longwavelength beams and the attenuation of solar background radiation in this region, long-distance optical communication becomes possible (17,18). In addition, progress has been made in the transmission of low-loss MIR optical signals in guided-wave optical systems (19)(20)(21), which will help to expand the communication distance of fiber-optic networks. Whether in waveguide or free-space systems, extending quantum technology to this band is very promising.…”