Figure 1
Overview of the Lab-in-a-Fiber device. The device consists of two modules. (a) Dispersed (disp.) phase droplets generated via flow focusing. The central hole of a five-hole capillary was fed with the dispersed phase and the exterior four holes were fed with the continuous (cont.) phase oil. A secondary capillary placed in close proximity to the output of the five-hole capillary forced the oil into the dispersed phase path, facilitating droplet generation via flow focusing. (b) Widefield microscopy image of droplets produced from 1 \(\upmu\)M fluorescein. They were measured to be approximately 120 \(\upmu\)m in diameter. (c) Fluorescence detection of droplets. Delivery of excitation light and collection of fluorescence emission was achieved on-axis using a periscope fiber (a double-clad fiber (DCF) cleaved at an angle of \(45^\circ\) and coated with aluminum). (d) Cross-sectional view of the periscope fiber secured in parallel to the droplet capillary. The 8 \(\upmu\)m core of the periscope fiber was used to couple continuous wave (CW) laser light to the droplets beneath, as indicated by the blue arrow. The induced fluorescence was collected through the 50 \(\upmu\)m \(1{\mathrm{st}}\) cladding region, as indicated by the green arrows. Note that the length of the Lab-in-a-Fiber device is not shown to scale, but indicative lengths of each section are given.
