In the beginning of the 1980s, an intersection of physics, chemistry, and nanotechnology laid the foundation for microfl uidics. Micro uidics allowed fast and controlled manipulation of very small volumes of uid, a nd t hese c apabilities op ened ne w a venues i n opt ics. e i ntegration o f m icro uidics with optoelectronic components became known as optofl uidics (Psaltis et al. 2006, Monat et al. 2007). is integration t hrove t wofold. First, it a llowed t he integration of opt ical components into lab-on-a-chip devices, known also as “micro total analysis systems” (µTAS). Second, it inherited the methods used in micro uidics to build new optical elements and attain new functionalities. In this chapter, we focus on those opt ical elements and devices t hat are based on integrated opto uidic components. ro ughout this chapter, we use the term fl uid in its broad sense, meaning liquid or gaseous phases of substances, and pure or mixed liquids including solutions and colloids.