We show how the ultrafast laser inscription of nanodimple arrays enables near-field local enhancement in high refractive-index crystals. We first demonstrate both experimentally and numerically how, when two nanodimples are separated by intermediate distances (700-1000 nm), near-field interference can take place resulting in a near-field enhancement between nanodimples. Based on this effect, near-field enhancements close to 60% are then demonstrated at the center of nanodimple arrays, and strong optical contrasts in excess of 100% are produced. The integration of these arrays into crystal substrates provides a versatile tool for new optical trapping and evanescent-field nanosensing devices.
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