Silver Mirrors for Ultrafast Lasers (550 – 1100 nm)

Silver Mirrors Optimized for Laser Applications

Special Features

• High reflectance in the VIS and NIR
• Very broad reflectance band with GDD ≈ 0 fs²
• Silver mirrors with defined transmittance (e.g. 0.01 %) exhibit high LIDT (see table) and the same reflectance and GDD values as shown in Fig. 1 and Fig. 2
• Extremely low scattering losses (total scattering TS ≈ 30 ppm in the VIS and NIR)
• Lifetimes of more than 10 years have been demonstrated in normal atmosphere
• Highly stable optical parameters due to sputtered protective layers
• Easy to clean (tested according to MIL-M-13508C § 4.4.5)

Stock of standard components

• Standard and fs-optimized protected silver on substrates with Ø = 12.7 mm, Ø = 25 mm and Ø = 50 mm:
  • Plane
  • Plano/concave and plano/convex with a variety of radii between 10 mm and 10 000 mm
• Other sizes, shapes, radii and coatings for other wavelength ranges on request

Coating	Reflectance*	Wavelength Range	LIDT**
fs-optimized protected silver	R = 96.5 … 98.5 %	600 – 1000 nm	0.38 J/cm²
Enhanced silver 800 nm	R > 99 %	700 – 900 nm	0.37 J/cm²
Broadband enhanced silver	R = 98 … 98.5 %	600 – 1200 nm	0.24 J/cm²
Partially transparent silver	R = 96.5 … 98.5 %	600 – 1000 nm	0.22 J/cm²
* For unpolarized light at AOI = 45°
** Measurements were performed at Laser Zentrum Hannover according to ISO 11254 measurement conditions: pulse duration: 150 fs, 30000 pulses, repetition rate: 1 kHz, λ = 800 nm

Silver Mirrors with Enhanced Reflectance

The reflectance of silver mirrors can be enhanced by an additional dielectric coating. The bandwidth of the enhanced reflectance must be exactly specified. Outside this band, the reflectance of the mirror may be lower than that of a standard silver mirror. For the use with fs-lasers, the additional dielectric coating must be optimized for high reflectance and low GDD. The following figures show examples for silver mirrors with enhanced reflectance at a specified wavelength (Fig. 3 and Fig. 4) and over the wavelength range of the Ti:Sapphire laser (Fig. 5). Enhanced silver mirrors can also be designed for a defined transmittance (e.g. T = 0.01 %).