FIG. 2.

(Left) Experimental apparatus consisting of the following elements: needle located inside a glass cylindrical capillary (A), high-precision orientation-translation systems (B), digital camera (C), optical lenses (D), triaxial translation stage (E), optical fiber (F), optical table (G), and pneumatic anti-vibration isolation system (H). (Right) Details of the experimental cell (A): needle, glass cylindrical capillary, and bath in a glass optical cell. The connections between the components were made by using flexible tubes (under pressure).