A capillary comprises a capillary channel, an inner layer, and an outer layer, wherein the inner and outer layers comprise different silica materials. An axicon lens formed on a facet end of the capillary channel has a selected geometry, such that the inner layer has an axicon angle γ and a post angle α. The inner layer may be fused silica and the outer layer may be borosilicate glass. The post angle α is determined in part by an etch rate constant of the borosilicate glass and an etch rate constant of the fused silica in at least one etching reagent. Embodiments may comprise at least two capillary channels, and an axicon lens formed on a facet end of each of the at least two capillary channels. The capillary may be used as an electrospray emitter, optionally with light simultaneously while generating an electrospray.