# Impact of Cubic Symmetry on Optical Activity of Dielectric 8-srs Networks
## 4 Conclusions  
We have fabricated 8-srs PhCs using a symmetry-preserving laser direct fabrication method. The numerically and experimentally characterized transmission properties of 8-srs networks reveal the influence of cubic symmetry on optical properties. Specifically, we have demonstrated that by using GD correction, cubic symmetry of the structures is greatly improved. Optically, OA and PSB intensity, position, and bandwidth can be modulated by adjusting cubic symmetry. The 8-srs PhCs fabricated in this work are optically active materials that can finely control in three-dimensions the propagation of light in mid-IR and tune rotation of the polarization plane of light by 1 Rad through a layer of four-unit cells. The 8-srs PhCs can be considered for gas or liquid sensing due to their ability to detect refractive index changes in the material they are immersed in. OA through a gas filled interaction volume serves as a sensing signal for determination of gas composition or concentration. Moreover, thickness, PSB, and OA are crucial prerequisites for many ultra-thin optical devices such as optical filters [39; 40; 41] and polarization rotators [42; 43].  
The following are available online at [[http://www.mdpi.com/2076-3417/8/11/2104/s1](http://www.mdpi.com/2076-3417/8/11/2104/s1)]([http://www.mdpi.com/2076-3417/8/11/2104/s1](http://www.mdpi.com/2076-3417/8/11/2104/s1)), Figure S1: Axial and lateral linewidths obtained from SEM images taken along the [011] direction. (a) In this configuration the sample is tilted by an angle of 45\({}^{\circ}\), therefore the lateral dimension \(\Delta\)X can directly be extracted by the images. To obtain the real \(\Delta\)Z value, it is necessary to multiply the measured value by \(\sqrt{2}\). (b) SEM image of 2-srs PhC fabricated using DLW and corresponding values of \(\Delta\)X, \(\Delta\)Z and \(e\). (c) SEM image of 2-srs PhC fabricated using GD-DLW and corresponding values of \(\Delta\)X, \(\Delta\)Z and \(e\). The software used for the measurements is ImageJ; Figure S2: SEM image of 8-srs PhCs fabricated using GD-DLW demonstrating the beneficial effects of the galvo-dithering on the mechanical stability. The power of the laser (P) is varied from 0.6 mW to 1 mW and the galvo-dithering radius (R) is varied from 0 nm to 900 nm; Figure S3: Experimental transmission spectra for 8-srs PhC fabricated via DLW (R = 0).  
All authors conceived the original idea. [PERSON] carried out the PhCs fabrication, characterization and numerical calculations. All authors analyzed the results and reviewed the manuscript.  
This research was conducted by the Australian Research Council Centre of Excellence for Ultrahigh-bandwidth Devices for Optical Systems (project number CE110001018).  
[PERSON] acknowledges support from the Australian Research Council Centre of Excellence for Ultrahigh-bandwidth Devices for Optical Systems (project number CE110001018). We thank the support of the RMIT Microscopy and Microanalysis Facility at RMIT University.  
The authors declare no conflicts of interest. The funders had no role in design of the study; collection, analyses, or interpretation of data; writing of the manuscript; or the decision to publish results.