Photonic devices on planar and curved substrates and methods for fabrication thereof

摘要

A versatile and rapid sol-gel technique for the fabrication of high quality one-dimensional photonic bandgap materials. For example, silica/titania multi-layer materials may be fabricated by a sol-gel chemistry route combined with dip-coating onto planar or curved substrate. A shock-cooling step immediately following the thin film heat-treatment process is introduced. This step was found important in the prevention of film crack formation—especially in silica/titania alternating stack materials with a high number of layers. The versatility of this sol-gel method is demonstrated by the fabrication of various Bragg stack-type materials with fine-tuned optical properties by tailoring the number and sequence of alternating layers, the film thickness and the effective refractive index of the deposited thin films. Measured optical properties show good agreement with theoretical simulations confirming the high quality of these sol-gel fabricated optical materials.

主权项

1. A sol-gel method for forming a material layer on a substrate, the method comprising:
depositing a layer of a sol-gel material that includes a dispersed solid phase and a solvent onto at least a portion of the substrate to produce a coated substrate, wherein the substrate is exposed to constant humidity and/or solvent vapor pressure during the depositing; evaporating the solvent from the sol-gel material deposited onto the substrate by exposing the deposited layer of sol-gel material to a hot air stream, wherein the evaporating is accomplished in a time ranging from 1 second to 10 seconds under a hot air stream having a temperature of 50° C. to 200° C.; calcining the substrate with the deposited layer of sol-gel material at a temperature of 250° C. to 500° C. for 1 second to 1 hour; and cooling the calcined substrate from the calcining temperature to room-temperature or less in 3 seconds or less by at least one of contacting the coated and calcined substrate with a heat-sink or immersing the coated and calcined substrate in a volume of liquid to yield the material layer on the substrate.