We investigate the optomechanical properties of a periodic array of identical scatterers placed inside an optical cavity and extend our previous results [Xuereb, Genes, and Dantan, Phys. Rev. Lett. 109, 223601 (2012)]. We show that operating at the points where the array is transmissive results in linear optomechanical coupling strengths between the cavity field and collective motional modes of the array that may be several orders of magnitude larger than is possible with an equivalent reflective ensemble. We describe and interpret these effects in detail and investigate the nature of the scaling laws of the coupling strengths for the different transmissive points in various regimes. The ability to measure and control the motion of massive mechanical oscillators has progressed dramatically in recent years [1,2], and several important milestones have been reached in the field of optomechanics towards bringing this capability into the quantum regime, including the cooling to the motional quantum ground state [3][4][5], the detection of quantized mechanical motion [6,7], and the observation of ponderomotive squeezing of light [8,9] or of radiation-pressure shot noise on a mechanical oscillator [10].One challenge faced by the current generation of optomechanical experiments is that the interaction strength between a single photon and a single massive mechanical element is typically very weak. This can be ameliorated by confining light in wavelength-scale structures [11] or, generically, counteracted by the use of strong light fields in an optical resonator to amplify the interaction strength [12], albeit at the expense of trading off the intrinsically nonlinear nature of the radiation-pressure interaction (see, however, recent proposals in Refs. [13,14]). A growing number of theoretical proposals have contemplated the opposite, a "strong coupling" regime, where a single photon can affect the motion of the oscillator significantly, thus giving access to the full quantum nature of the optomechanical interaction [15][16][17][18][19][20][21][22][23].On the other hand, collective effects in optomechanical systems involving multiple mechanical and electromagnetic field modes have been discussed in a number of theoretical works, in connection with, e.g., optomechanical entanglement [24][25][26][27][28][29][30][31][32][33][34] Motivated by the exploration of such collective optomechanical effects, we recently [58] showed that the collective motion of a periodic array of identical scatterers, when placed inside a cavity field, can couple very strongly to the optical field in the configuration where the array is transmissive, in contrast to the usual reflective optomechanics approach. The aim of the present work is to present a detailed exploration of this system in order to highlight the regimes in which these generic collective effects are seen and to compare the various possible transmissive operating points.This paper is organized as follows. In the next section we summarize and discuss the tools used to model a periodic ...