High efficiency diffraction gratings for laser tuning
When ordering a grating, please use the following example format, or choose from the grating stock list below.

G 1100 W x H x Thk 1200-1600 nm (TM/-1) constant incidence angle 75°

• G stands for Grazing incidence, P for Plano and L for Littrow gratings (optional information)
• 1100 is the groove density (groove frequency) in grooves/mm
• W is the blank dimension in mm parallell with the grating grooves
• H is the blank dimension in mm perpendicular to the grating grooves
• Thk is the blank thickness in mm
• 1200-1600 nm is the desired optimisation range. A specific wavelength or range with peaked wavelength can also be specified
• (TM/-1) is desired polarisation state and diffraction order the grating should be optimised for. TE and average (TM+TE)/2 can also be specified
• Constant incidence angle 75° is the configuration the grating should be optimised for. Constant deviation θ° can also be specified

Standard grating products. For stock info, please contact our sales department.

Note: The absolute efficiency curves shown are only representative for the stated geometry and wavelength(s) and can vary depending on use geometry and measurement technique.

Standard tolerances on W, H: ± 0.2 mm, Thk ± 0.5 mm. CA > 90 % of each dimension.

Other specifications available on request, contact our sales department!

Plane Gratings for laser tuning
Laser tuning gratings are holographic gratings specially designed for wavelength tuning of lasers, such as dye lasers, Ti-sapphire, or external cavity diode lasers. The groove depth is optimised to yield maximum efficiency for one state of polarisation.

Extremely low stray light
The holographic masters, used for our dye laser gratings, are fabricated with the same technique as our low stray light gratings. This results in very small amounts of scattered light, comparable to that from a good front surface aluminium mirror.

High efficiency
The groove depth of these sinusoidal groove gratings, is optimised to give maximum efficiency for TM polarisation (the electric vector perpendicular to the grooves). Depending on the wavelength and configuration, the TM efficiency may be more than 80 %, and in some cases better than 90 % (absolute efficiency).

Littrow gratings
The Littrow mount, or auto collimatlon, is the classical configuration for laser tuning. The laser beam has to be expanded by intracavity optics, in order to fill the grating aperture and obtain high resolution. The Littrow configuration is also often used for external cavity tuning of diode lasers. Especially in the NIR, very high efficiency (>90 %) can be achieved.

Grazing incidence Littman gratings
The grazing incidence, or Littman configuration is the most common configuration for dye laser tuning. No beam expansion is needed; high resolution is accomplished by illuminating the grating in a fixed grazing incidence angle. A flat, tiltable mirror is used for wavelength tuning.