Manipulation of surface plasmons on a vertical cavity surface emitting laser platform

摘要

The use of structured metal films where electromagnetic waves are confined and manipulated as surface plasmon polaritons (SPPs) has potential use in applications ranging from biosensing, chip-to-chip optical interconnects and in data storage. In general, the SPPs are excited using a separate light source which compromises the compactness of any system. As a solution the SPPs can be directly excited on a layer of gold which is deposited on the top surface of a Vertical Cavity Surface Emitting Laser. Here, we have designed the surface of the VCSEL to include a customised planar gold layer upon which we can excite, propagate and manipulate SPPs over distances of up to 100 microns. We launch the SPPs using a low threshold 850 nm emitting VCSEL under continuous wave operation using a diffraction grating etched through the gold surface. Shallow etched gratings are used to manipulate the SPPs through, for example, a 90° bend using a Bragg mirror and to out-couple the SPPs into air where the polarization dependent relative intensity of the extracted light is measured using a CCD camera. We measure a SPP propagation length of about 50 microns. The result paves the way to compact integrated plasmonic devices.