Desai Gaarde (crookafrica04)

Non-invasive determination of the optical properties is essential for understanding the light propagation in biological tissues and developing optical techniques for quality detection. Simulation-based models provide flexibility in designing the search space, while measurement-based models can incorporate the unknown system responses. However, the interoperability between these two types of models is typically poor. In this research, the mismatches between measurements and simulations were explored by studying the influences from light source and the incident and detection angle on the diffuse reflectance profiles. After reducing the mismatches caused by the factors mentioned above, the simulated diffuse reflectance profiles matched well with the measurements, with R2 values above 0.99. Successively, metamodels linking the optical properties with the diffuse reflectance profiles were respectively built based on the measured and simulated profiles. MDL-800 chemical structure The prediction performance of these metamodels was comparable, both obtaining R2 values above 0.96. Proper correction for these sources of mismatches between measurements and simulations thus allows to build a simulation-based metamodel with a wide range of desired optical properties that is applicable to different measurement configurations.Spectral filters are important building blocks for many applications in integrated photonics, including datacom and telecom, optical signal processing and astrophotonics. Sidewall-corrugated waveguide grating is typically the preferred option to implement spectral filters in integrated photonic devices. However, in the high-index contrast silicon-on-insulator (SOI) platform, designs with corrugation sizes of only a few tens of nanometers are often required, which hinders their fabrication. In this work, we propose a novel geometry to design complex Bragg filters with an arbitrary spectral response in silicon waveguides with laterally coupled Bragg loading segments. The waveguide core is designed to operate with a delocalized mode field, which helps reduce sensitivity to fabrication errors and increase accuracy on synthesized coupling coefficients and the corresponding spectral shape control. We present an efficient design strategy, based on the layer-peeling and layer-adding algorithms, that allows to readily synthesize an arbitrary target spectrum for our cladding-modulated Bragg gratings. The proposed filter concept and design methodology are validated by designing and experimentally demonstrating a complex spectral filter in an SOI platform, with 20 non-uniformly spaced spectral notches with a 3-dB linewidth as small as 210 pm.Reliable in situ water-leaving radiance (Lw) measurements are critical for calibrating and validating the ocean color products from remote platforms (e.g., satellite). In an experimental effort, Wei et al. [Opt. Express29, 2780 (2021)10.1364/OE.413784] reported that the on-water radiometry allows for high-precision radiance determination. Zibordi [Opt. Express29, 19214 (2021)10.1364/OE.421786] questioned the use of the "1% radiometry" term in the former and commented on the data collection with the sensor's optical window submerged in water. This reply responds to the comments and discusses the on-water data processing protocol, which shows the obtained Lw is not affected by the questions raised therein.This work aims at commenting requirements and conclusions in a recent paper [Wei et al., Opt. Express29, 2780 (2021)10.1364/OE.413784] presenting an evaluation of the precision of water-leaving radiance measurements from a near-surface method. Specifically, this work challenges the uncertainty requirements indicated for satellite ocean color system vicarious calibration resulting from an erroneous interpretation of literature, and an incorrect application of radiometry principles leading to a misestimate of the difference between radiances collected by nadir-view optical sensors operated bel