Helium Lines (4.00 – 4.50 microns)
Infrared Helium Lines
| Atomic Line | Transition | Wavelength (um) |
| HEI | 5P-4D,1Po-1D | 04.0064 |
| HEI | 5F-4D,3Fo-3D | 04.0376 |
| HEI | 5F-4D,1Fo-1D | 04.0407 |
| HEII | 10-8 | 04.0495 |
| HeI | 4f-5g/4d-5f? | 04.052 |
| HEI | 5D-4F,1Fo-1D | 04.0547 |
| HEI | 5D-4F,3D-3Fo | 04.0570 |
| HEII | 15-10 | 04.1001 |
| HEI | 5D-4P,1D-1Po | 04.1227 |
| HEII | 19-11 | 04.1457 |
| HEII | 12-9 | 04.2173 |
| HEI | 5P-4D,3D-3Po | 04.2440 |
| HEII | 25-12 | 04.2619 |
| HEI | 3P-3S,3Po-3S | 04.2959 |
| HEII | 24-12 | 04.3720 |
| HEII | 18-11 | 04.3988 |
| HEII | 23-12 | 04.5048 |