In this work, an influential approach has been presented for the fabrication of an interference filter. The construction of such filters turns the layer stack assembly on its one side which makes it possible to use air as a low index material. All the layers of a particular material (high index) are deposited at the same time which transforms the layer thickness into line thickness and is obtained by patterning the filters using photolithography. This results in the formation of a complex filter design with high volume and low production cost.
There are several trace gases such as N2O, CO, CO2, NO, H2O, NO2, NH3, CH4 etc. which have their absorption peaks in Mid-IR spectrum These gases strongly absorb in the mid-IR > 2.5 μm spectral region due to their fundamental rotational and vibrational transitions. In this work, we modelled and optimized three different kinds of waveguides such as rib, strip and slot based on silicon platform to obtain maximum evanescent field ratio. These waveguides are designed at 3.39 μm and 4.67 μm which correspond to the absorption line of methane (CH4) and carbon monoxide (CO) respectively.
In this work, narrowband pass and broadband pass filters are designed based on TiO2-SiO2 multilayers. These filters are used in observing planetary nebulas and emission nebulas. They are designed by using open source software open filter and optimized by using needle synthesis method (addition of thin layers called needles and analyze transmission till the best result achieved). Also results were cross-checked by using matrix method. The transmission of these filters is in the range of 486-501 nm (Oxygen-III and hydrogen-β) with a maximum transmission of 95%. Also it has a second peak at 656 nm for hydrogen-α where transmission reaches 87%.
Sunlight can be used a source of light in buildings and automobiles, however infrared wavelengths in sunlight result in heating. In this work, Infrared Reflective Coatings are designed using thin films to transmit visible wavelengths 400~700 nm while reflecting infrared wavelengths above 700 nm. Three different design approaches have been used, namely single layer of metal, sandwich structure and multilayer design. Four metals (Ag, Au, Al and Cu) and two dielectrics (TiO2 and SiO2) are used in this study. Designs with Ag show maximum reflection of Infrared wavelengths in all designs. Sandwich structures of TiO2-Ag-TiO2 on substrate with 22 nm of thickness for each layer show the maximum transmission of 87% in the visible region and maximum reflection of Infrared wavelengths.
This paper presents the design and simulation of a 3-DOF (degree-of-freedom) MEMS gyroscope structure with 1-DOF drive mode and anchored 2-DOF sense mode, based on UV-LIGA technology. The 3-DOF system has the drive resonance located in the flat zone between the two sense resonances. It is an inherently robust structure and offers a high sense frequency band width and high gain without much scaling down the mass on which the sensing comb fingers are attached and it is also immune to process imperfections and environmental conditions. The design is optimized to be compatible with the UV-LIGA process, having 9 μm thick nickel as structural layer. The electrostatic gap between the drive comb fingers is 4 μm and sense comb fingers gap are 4 μm/12 μm. The damping effect is considered by assuming the flexures and the proof mass suspended about 6 μm over the substrate. Accordingly, mask is designed in L-Edit software.
In this work, we have demonstrated the use of different technologies to fabricate straight channel waveguides, S-bend waveguides, Y-splitter and Mach-Zehnder (MZ) structures on RbTiOPO4 crystals and its isomorphs. We used reactive ion etching (RIE), inductively coupled plasma-RIE (ICP-RIE), femtosecond pulse laser micro-fabrication and ion diffusion techniques to structure these crystals. Computer simulations have been carried out and compared with the optical characterization of the waveguides which are in agreement with each other.