In recent years, high-density optical data storage has been attracting much interest toward future Tera byte memories. An optical near-field technology is considered to make a breakthrough for ultrahigh capacity optical storages beyond the diffraction-limit. We proposed and demonstrated a micro/nano metal aperture VCSEL for producing optical near-field. Recently, we successfully demonstrated the optical probing based on a micro/nano aperture VCSEL using reflection-induced voltage change of a VCSEL.
We fabricated a nano-aperture GaAs VCSEL with various aperture sizes ranging from 100 to 840 nm. The lasing wavelength is 850 nm. We formed a nano-aperture by using focus ion beam etch on a 130 nm thick Au film deposited on the VCSEL surface. The threshold is as low as 0.3 mA. An AFM probe is scanned just above the nano-aperture of the VCSEL. The distance between the fiber probe and the VCSEL was controlled in the contact mode of an AFM (atomic force microscope) system. We successfully demonstrated the 2D imaging of the voltage change of a nano-aperture VCSEL. The maximum voltage change is 0.47 mV.
In this paper, we carried out the modeling and the experiment of optical nano-probing with a metal-aperture VCSEL. We will discuss the effect of surface plasmon excitation in our proposed nano optical probing.