fs Laser Optics optimized for Third Order Dispersion

This very special type of optical coatings can be used to compensate the third order dispersion which results from laser crystals, substrates or dispersive elements as prisms or gratings. Positive as well as negative TOD can be achieved with this type of coatings. All coatings are optimized for nearly constant TOD which means TOD oscillations in the order of some hundreds of fs³. Please note that without TOD optimization these oscillations are in the order of some thousands of fs³. Recently, broadband mirror pairs with low average TOD were developed (see fig. 1). If low TOD over an extremely broad wavelength range is required we recommend to use optimized silver mirrors (see fig. 2).

Figure 1: Reflectance (a), GDD(b) and TOD spectra (c) of a mirror optimized for nearly constant negative third order dispersion

Figure 2: Reflectance (a), GDD(b) and TOD spectra (c) of a mirror optimized for nearly constant positive third order dispersion

• Central wavelength and amount of TOD according to customer specifications
• In the wavelength range of the Ti:Sapphire laser the bandwidth of single mirrors with optimized TOD is limited to about 150nm

Figure 3: Reflectance (a), GDD(b) and TOD spectra (c) of a mirror pair optimized for nearly constant negative third order dispersion

Figure 4: Reflectance (a), GDD(b) and TOD spectra (c) of a mirror pair optimized for broadband low third order dispersion

Mirror pairs show very smooth GDD and TOD spectra, although the corresponding spectra of the single mirrors exhibit strong oscillations. Broadband low TOD mirror pairs (e.g. for a bandwidth of 400 nm, see fig. 4) are available.

Figure 5: TOD spectrum of a fs-optimized silver mirror (turning mirror for 600 - 1000 nm)