Development of the Broadband and Dual-band Cavity Mirrors for SR-FEL at 355nm and 248nm
- Received Date: 2006-08-08
- Accepted Date: 2006-09-14
- Available Online: 2007-04-05
Abstract: The cavity mirrors of the storage-ring free-electron laser (SR-FEL) at 355nm and 248nm central wavelengths have been developed with the technologies of electron-beam evaporation deposition and ion-beam sputter deposition. The mirror coatings consists of “HfO2/SiO2+Al2O3/SiO2+M-SiO2”.The absolute reflectance and frequency-tunable range at 355nm are R=99.45% and Δλ(R≥99.00%)=75nm, respectively, for the broadband resonator mirror. For the mirror with the dual-central wavelengths, R=99.69% and Δλ(R≥99.00%)=59nm for the first band at 355nm; For the second band at 248nm, R=98.21%, Δλ(R≥99.00%)=9nm and Δλ(R≥98.00%)=51nm.