An optofluidic device is provided. The device includes a cladding region having a first refractive index, and a channel defined by the cladding region such that the cladding region forms an inner surface or an interface of the channel. The channel is configured to house one or more of a liquid, a solid, a gas, a colloidal, or a suspension sample, wherein the sample has a second refractive index, where the channel is configured to guide radiation, and where the first refractive index is lower than the second refractive index.