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Silver Mirrors for fs Laser Optics
Silver Mirrors optimized for Femtosecond Applications
Special Features:
- High reflectance in the VIS and NIR
- Very broad reflectance band with GDD ∼ 0fs2
- Silver mirrors with defined transmission (e.g. 0.01%) show high LIDT-values (see table 1) and the same R and GDD values as shown in figures 1 and 2
- Extremely low straylight losses (TS ∼ 3x10-5 in the VIS and NIR)
- Lifetimes of more than 10 years in normal atmosphere were demonstrated
- Highly stable optical parameters because of sputtered protective layers
- Good cleanability (tested according to MIL-M-13508C § 4.4.5)
- Laser induced damage threshold for fs-pulses:
Coating | Reflectance* | Wavelength range | LIDT [J / cm2]** |
---|---|---|---|
fs- optimized protected silver | R = 96.5 ... 98.5 % | 600 - 1000 nm | 0.38 |
Enhanced silver 800 nm | R > 99 % | 700 - 900 nm | 0.37 |
Broadband enhanced silver2 | R = 98 … 98. 5 % | 600 - 1200 nm | 0.24 |
Partially transparent silver | R = 96.5 % - 98.5 % | 600 - 1000 nm | 0.22 |
* | For unpolarized light at AOI = 45° |
** | Measurements were performed at Laser Zentrum Hannover according to ISO 11254 measurement conditions: pulse duration: 150 fs, 30 000 pulses, repetition rate 1kHz, λ = 800 nm |
Stock of Standard Components:
- Standard and fs - optimized protected silver on substrates with ∅ =12.7mm, ∅ = 25mm and ∅ = 50mm:
- Plano,
- Plano /concave and plano / convex with a variety of radii between 10mm and 10000 mm
- Other sizes, shapes, radii and coatings for other wavelengths ranges on request
Silver Mirrors with Enhanced Reflectivity
The reflectance of silver mirrors can be enhanced by a dielectric overcoat. The bandwidth of the enhanced reflectivity must be exactly specified. Outside this band the reflectivity of the mirror may be lower than that of a standard silver mirror. For use with fs-lasers, the dielectric overcoat must be optimized for high reflectivity and low GDD. The following figures show examples for silver mirrors with enhanced reflectivity at a specified wavelength (figures 3 and 4) and over the wavelength range of the Ti:Sapphire laser (figure 5).
Also enhanced silver mirrors can be designed for a defined transmission (e.g. T = 0.01 %).