“…[3][4][5][6][7][8][9][10][11][12][13][14] Comprised of a subwavelength modulation in RI, such structures can produce complete exchange of energy between forward-and backward-propagating diffracted waves with smooth line shapes and arbitrarily low line widths. 5-7 PC structures displaying guided-mode resonances ͑GMRs͒ have been successfully used to develop optical filters, 15-18 polarizers, 6,19 light modulators, 20 wavelength-division multiplexing devices, 21 vertically emitting lasers, 22 light-emitting diodes with improved extraction efficiency, 23-25 optical nanoelectromechanical transducers, 26,27 humidity sensors, 28 labelfree biosensors, 29-32 enhanced-fluorescence biosensors, [33][34][35][36][37] and substrates for surface-enhanced Raman spectroscopy.…”