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The field of silicon photonics is based on introducing and exploiting advanced optical functionality. Current efforts in the field are based on conventional micro/nanofabrication methods, leading to optical functionality over wafer surfaces. A complementary and emerging field is introducing analogous optics directly within the wafer using lasers. Here we investigate the theoretical feasibility of a subclass of such optics, photonic crystals. Our efforts will guide future experimental efforts towards in-chip spectral control. [ABSTRACT FROM AUTHOR]

The trend toward ever‐increased speeds for microelectronics is challenged by the emergence of heat‐wall, leading to the faltering of Moore's Law. A potential solution may be integrating microfluidic channels into silicon (Si), to deliver controlled amounts of cooling fluid and regulate hot spots. Such meandering microfluidic channels within other transparent materials already played significant roles, including in biomedical and sensor applications; however, analogous channel architectures do not exist in Si. Here, a novel method is proposed to fabricate buried microchannel arrays monolithically integrated into Si, without altering the wafer surface. A two‐step, laser‐assisted subtractive removal method is exploited, enabling fully‐buried multi‐level architectures, with control on the channel port geometry, depth, curvature, and aspect ratio. The selective removal rate is 750 µm per h per channel, and the channel inner‐wall roughness is 230 nm. The method preserves top wafer surface roughness of 2 nm, with significant potential for 3D integrated systems. [ABSTRACT FROM AUTHOR]

The article reviews surface plasmon resonance (SPR), localized SPR and large-scale plasmonic arrays. Topics discussed include a description of the theories of SPR and LSPR by demonstrating the main experimental architecture and operational modes at present, the integration of microfluidic platforms and plasmonic technologies and the present state-of-the-art plasmonic-based LOC biosensors as well as the future of plasmonic technologies for diagnostics and monitoring of various types of diseases.

Keywords: 3D microfabrication; laser lithography; microchannels; nonlinear laser interactions; siliconMonolithically Integrated ChannelsIn article number 2301617, Onur Tokel and co‐workers present a novel laser‐lithography method, enabling the fabrication of micro‐channels monolithically integrated into silicon. The method is used to create buried multi‐level architectures, with robust control on geometry, depth, curvature, and aspect ratio. The wafer surface is preserved, establishing a path towards three‐dimensional integration..By Muhammad Ahsan Tauseef; Rana Asgari Sabet and Onur TokelReported by Author; Author; Author [Extracted from the article]

Laser direct writing is a widely employed technique for 3D, contactless, and fast functionalization of dielectrics. Its success mainly originates from the utilization of ultrashort laser pulses, offering an incomparable degree of control on the produced material modifications. However, challenges remain for devising an equivalent technique in crystalline silicon which is the backbone material of the semiconductor industry. The physical mechanisms inhibiting sufficient energy deposition inside silicon with femtosecond laser pulses are reviewed in this article as well as the strategies established so far for bypassing these limitations. These solutions consisting of employing longer pulses (in the picosecond and nanosecond regime), femtosecond‐pulse trains, and surface‐seeded bulk modifications have allowed addressing numerous applications. [ABSTRACT FROM AUTHOR]

Timely detection of infectious agents is critical in early diagnosis and treatment of infectious diseases. Conventional pathogen detection methods, such as enzyme linked immunosorbent assay (ELISA), culturing or polymerase chain reaction (PCR) require long assay times, and complex and expensive instruments, which are not adaptable to point-of-care (POC) needs at resource-constrained as well as primary care settings. Therefore, there is an unmet need to develop simple, rapid, and accurate methods for detection of pathogens at the POC. Here, we present a portable, multiplex, inexpensive microfluidic-integrated surface plasmon resonance (SPR) platform that detects and quantifies bacteria, i.e., Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) rapidly. The platform presented reliable capture and detection of E. coli at concentrations ranging from ~105 to 3.2 × 107 CFUs/mL in phosphate buffered saline (PBS) and peritoneal dialysis (PD) fluid. The multiplexing and specificity capability of the platform was also tested with S. aureus samples. The presented platform technology could potentially be applicable to capture and detect other pathogens at the POC and primary care settings. [ABSTRACT FROM AUTHOR]

[Display omitted] • A special selective wet chemical etchant is developed and optimized for removal of subsurface laser modified c-Si. • The etch recipe is non-toxic while yielding smooth surfaces at a high etch rate and selectivity for laser-processed Si. • The champion etchant exhibits a selectivity of over 1600 times for laser modified c-Si with respect to unmodified c-Si. • Extremely high aspect ratios > 13 are achieved in 3D structuring of c-Si. • The etch rate and selectivity, as well as their calculations, are redefined to include 3D aspects both at the surface and the subsurface of c-Si. Recently-demonstrated high-quality three-dimensional (3D) subsurface laser processing inside crystalline silicon (c-Si) wafers opens a door to a wide range of novel applications in multidisciplinary research areas. Using this technique, novel maskless micro-pillars with precise control on the surface reflection and coverage are successfully fabricated by etching the laser-processed region of the c-Si wafer. To achieve this, a particular selective wet chemical etching is developed to follow subsurface laser processing of c-Si to reveal the desired 3D structures with smooth surfaces. Here, we report the development of a novel chromium-free chemical etching recipe based on copper nitrate, which yields substantially smooth surfaces at a high etch rate and selectivity on the both laser-processed Si surface and subsurface, i.e., without significant etching of the unmodified Si. Our results show that the etch rate and surface morphology are interrelated and strongly influenced by the composition of the adopted etching solution. After an extensive compositional study performed at room temperature, we identify an etchant with a selectivity of over 1600 times for laser-modified Si with respect to unmodified Si. We also support our findings using density functional theory calculations of HF and Cu adsorption energies, indicating significant diversity on the c-Si and laser-modified surfaces. [ABSTRACT FROM AUTHOR]