Table 2.
Transmission difference between system with air and with each value of concentration and equivalent path length in free space measuring, as well as the ratio between this path length and the minimum path length for the metasurface (0.15 mm).
| Gas concentration |
|
|
|
|---|---|---|---|
100 ppm 
|
0.016 | 56.5 cm | 3767 |
1000 ppm 
|
0.139 | 52.5 cm | 3500 |
5000 ppm 
|
0.418 | 38.3 cm | 2553 |
10000 ppm 
|
0.514 | 25.8 cm | 1720 |
| 10 ppm HCN | 0.009 | 17.1 cm | 1140 |
| 100 ppm HCN | 0.079 | 15.5 cm | 1033 |
| 500 ppm HCN | 0.241 | 10.4 cm | 693 |
| 1000 ppm HCN | 0.278 | 6.2 cm | 413 |