Filters for Laser Applications (260 – 2500 nm)

Calibration Filters (300 – 5000 nm)

Fig.1:Transmission spectra of a sputtered multiline filter (VIS) to calibrate CCD-spectrometer (FHWM ≈ 1.5 nm at 546 nm)

Fig.2:Transmission spectra of a sputtered multiline filter (VIS) to calibrate CCD-spectrometer (FHWM ≈ 1 nm at 546 nm)

The number of lines and the spectral range are set according to customer requirements and are supplied with spectral measurement curves.

Spectral Graduated Filters (300 – 4000 nm)

These filters are developed for building spectrometers with inexpensive (smaller) CCD camera chips.

Fig.3:Small gradient filter

Fig.4:Calculated transmission for three different lateral positions of AOI = 0°

Special Features

Linear variation of the filter wavelength with respect to the lateral position on the filter
Blocking range: 200 to 1300 nm with OD2 to OD4
Filter area < sensor area
- simple geometrical adjustment by spectral pixel calibration and/or free positioning

Steep Edge Filters

Fig.5:Transmittance spectra of a steep edge short-wavelength pass filter for use as a combiner for laser diodes at 635 nm and 670 nm
HRu (22.5°, 670 nm) > 99.9 % + Ru (22.5°, 635 nm) < 2 %, rear side AR coated)

a)Section around the edge of the blocking band

b)Spectral overview

For more information on combiners for diode lasers see page Diode Lasers (620 – 680 nm, 808 – 990 nm). For steep edge filters used as pump mirrors for solid-state lasers based on Yb-doped materials (e.g. Yb:YAG, Yb:KGW, Yb-doped fibers) see page High Power Lasers on the Basis of Yb- and Nd-doped Materials (1020 – 1080 nm).

Narrowband Reflectance Filters

Filters of this type are ideal for the blocking of a single laser line while preserving a high and relatively constant transmittance over the whole visible range.

Fig.6:Reflectance spectrum of a narrowband reflectance filter for 550 nm

Special Features

Filters for laser applications require excellent spectral quality and high damage thresholds
Spectral position of cut-on/cut-off wavelengths or reflectance bands according to customer specification
Sizes and shapes: Edge filters can be produced on round or rectangular substrates up to diameters of 38.1 mm (1.5 inch). The production of miniature size filters (e.g. 3 × 3 mm²) is possible. Narrowband reflectance filters are limited to diameters of 25.4 mm (1 inch).
Optical parameters are environmentally stable

Dual Wavelength Filters with Broad Blocking Range

Fig.7:Reflectance spectra of a dual wavelength filter for 1064 nm and 1570 nm with a broadband blocking range from the UV to 2100 nm. Double side coating reduces the mechanical stress. Blocking in the UV/VIS is done by a optical filter glass.

a)Front side coating

b)Rear side coating

c)Combination of front and rear side coating

Filters for Laser Applications (260 – 2500 nm)

Calibration Filters (300 – 5000 nm)

Spectral Graduated Filters (300 – 4000 nm)

Special Features

Steep Edge Filters

Narrowband Reflectance Filters

Special Features

Dual Wavelength Filters with Broad Blocking Range

Filters for Laser Applications (260 – 2500 nm)

Calibration Filters (300 – 5000 nm)

Spectral Graduated Filters (300 – 4000 nm)