Diagnostic within a dielectric micro-structure: time-reversal and sparsity-constrained imaging

5 ppInternational audienceComputational imaging of micro-structured systemsas a grid-like set of a finite number of circular cylindricaldielectric rods is considered. How to achieve meaningful localization,resolution-enhanced or, even, super-resolved, vs. thewavelength(s) of operation if defects or radiators are to be foundwithin is discussed here. That is, the set can be seen from allaround when either a line source inside an intact system ofrods is to be localized, or when, now illuminated by exteriorline sources, there is an unknown distribution of missing rods.One-shot time-reversal (mostly reduced as time-harmonic backpropagation,though cases involving broadband transient datawill be proposed in the presentation) and iterative sparsityconstrainedjoint source imaging are analyzed as solution toolsin both TE and TM polarizations