Plasmon Enhanced Optical Near-field Probing of Metal Nanoaperture Surface Emitting Laser.

We demonstrate a metal nano-aperture GaAs vertical cavity surface emitting laser (VCSEL) for sub-wavelength optical near-filed probing, which exhibits the strong plasmon enhancement of both optical near-fields and voltage signals with forming a metal nano-particle in the nano-aperture. The threshold current is as low as 300microA, which shows a potential of nano-probing with low power consumption. We achieved the first demonstration of a plasmon enhanced VCSEL near-field probe. The spatial resolutions of the VCSEL probe with 400 nm and 200 nm apertures are 240nm and 130 nm, respectively. The enhancement factors of the optical near-field and voltage signal with a Au particle are 1.8 and 2, respectively. Our FDTD simulation shows that localized plasmon with a Au particle is very helpful for increasing optical near-field intensity and signal voltage in the VCSEL nano-probing.