Focused ion beam (FIB) milling is an emerging technology that enables fast, reliable and well-controlled nanometer-size feature definition. In this work we will discuss applications of the tool in the area of photonics. The FIB technique can be adapted and optimized almost for any material system since it involves physical removal of material by a beam of ions. Specific strategies can be developed in order to optimize the nano-structuring processes which are strongly dependent on the geometry of the desired structure. In this work we will report on the impact of parameters such as ion beam current, dwell time, scanning strategy, and dielectric charging on the nanofabrication process. As sample structures we will focus on gratings formed on optical waveguides in different material systems. The grating structures form the basic reflective elements in on-chip integrated waveguide laser devices. Straight sidewalls are desired for minimizing the out-of-plane losses. Both, high depth and straight sidewalls demand for a good control over the re-deposition of material taking place during the milling process. The grating structures were realized by use of a FEI Nova 600 dual beam FIB machine. The acceleration voltage was set to 30 kV. The milling current was varied between 93 pA and 280 pA. In order to analyze grating parameters such as grating depth or sidewall slope, cross-sectioning of the milled structures was performed. Pt was in-situ and locally grown in order to avoid material re-deposition while milling the cross-section. Different optimization processes were applied and good optical quality grating structures in the Al2O3, Y2O3 and KGdxLu1-x(WO4)2:Yb3+ material platforms were obtained. The effect of redeposition was minimized and an excellent control of the nano-structuring process has been achieved. Fabry-Pérot microcavities were defined and used to assess their optical performance. An on-chip waveguide laser in rare-earth-ion-doped materials was demonstrated.
|Number of pages||2|
|Publication status||Published - Sep 2013|
|Event||2013 Energy Materials Nanotechnology East Meeting, EMN East Meeting 2013 - Beijing, China|
Duration: 7 Sep 2013 → 10 Sep 2013
|Conference||2013 Energy Materials Nanotechnology East Meeting, EMN East Meeting 2013|
|Abbreviated title||EMN East Meeting|
|Period||7/09/13 → 10/09/13|
- IOMS-APD: Active Photonic Devices
Ay, F., & Pollnau, M. (2013). Focused-ion-beam nano-structuring of photonic cavities in dielectric materials. 38-39. Abstract from 2013 Energy Materials Nanotechnology East Meeting, EMN East Meeting 2013, Beijing, China.