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This letter describes an approach for recording three-dimensional ͑3D͒ periodic structures in a photosensitive polymer using a single diffraction element mask. The mask has a central opening surrounded by three diffraction gratings oriented 120°relative to one another such that the three first order diffracted beams and the nondiffracted laser beam give a 3D spatial light intensity pattern. Structures patterned in this polymer using 1.0 and 0.56 m grating periods have hexagonal symmetry with micron-to submicron-periodicity over large substrate area. Band structure calculations of these low index contrast materials predict photonic gaps in certain high symmetry directions.

A novel photothermal process to spatially modulate the concentration of sub-wavelength, high-index nanocrystals in a multicomponent Ge-As-Pb-Se chalcogenide glass thin film resulting in an optically functional infrared grating is demonstrated. The process results in the formation of an optical nanocomposite possessing ultralow dispersion over unprecedented bandwidth. The spatially tailored index and dispersion modification enables creation of arbitrary refractive index gradients. Sub-bandgap laser exposure generates a Pb-rich amorphous phase transforming on heat treatment to high-index crystal phases. Spatially varying nanocrystal density is controlled by laser dose and is correlated to index change, yielding local index modification to ≈+0.1 in the mid-infrared.

There is considerable research activity in multiresonator optical circuits in silicon photonics, e.g., for higher-order filters, advanced modulation format coding/decoding, or coupled-resonator optical waveguide delay lines. In diagnostics of such structures, it is usually not possible to measure each individual microring resonator without adding separate input and output waveguides to each resonator. We demonstrate a non-invasive diagnostic method of quantitative IR imaging, applied here to a series cascade of rings. The IR images contain information on the otherwise inaccessible individual through ports and the resonators themselves, providing an efficient means to obtain coupling, loss, and intensity-enhancement parameters for the individual rings.

This letter describes a simple synthetic approach to fabricate two-dimensional midinfrared CdSe photonic crystals ͑PC͒ by electrodeposition of CdSe in a polymer template defined using interference lithography. Characterization of the transmission spectra of CdSe PCs with a hexagonal array of 1.3 m diameter and 2.7 m pitch air voids showed a well-defined drop in transmission at 4.23 m. The drop in transmission increased with incident angle, reaching a maximum of approximately 2.6 dB at 40°relative to the surface normal. This two-step synthetic approach can be used to incorporate photonic crystals onto arbitrary substrates for integration into future advanced optical circuits.