Large-numerical-aperture InP lenslets by mass transport

Publisher Website
Google Scholar
Abstract
Lenslets with diameters up to 130 μm and numerical apertures of 0.39–0.75 have been formed in InP substrates by using mass transport to smooth out chemically etched multilevel mesa structures. The lenslets show a smooth surface with an accurately controlled profile (i.e., curvatures) and are capable of forming clear images. Some lenslets (with a diameter of approximately 67 μm) have been used to collimate the output of a buried-heterostructure diode laser (of 1.3 μm wavelength) and resulted in a nearly diffraction-limited beam divergence of 1.4°.