A simple and low-cost fabrication of polymeric vertical microlens using dip method

Polymeric vertical microlenses (PVMs) using photoresist material SU-8 are fabricated with a simple and low-cost process that can be easily applied to the microoptical/optoelectronic bench. By virtue of the strong adhesive force and liquid cohesion, the PVMs are formed by hanging the liquid SU-8 on walls by a dip method. Then, in order to enhance the thermal stability and reliability of the PVMs, the lenses are baked and exposed in the ultraviolet light to crosslink the SU-8. To characterize the PVMs, we use a single-mode fiber carrying a 1.55-μm wavelength laser light source and utilize BeamScope P5 to observe the beam convergences. The output beams through the PVMs show a vertical far-field angle of 3.04/spl deg/, as compared to 5.53/spl deg/ of the beam without passing through the lenses.