Features

• Designed for Frequency-Doubled Ultrafast Ti:Sapphire Laser Pulses
• Ideal for Laser Pulses Shorter than 250 fs
• Reflectance Greater than 99%
• Low Group Delay Dispersion: |GDD| < 30 fs²
• Available in Ø1/2" and Ø1" Sizes
• For Use at a 45° Incident Angle

These Low Group Delay Dispersion (GDD) Mirrors provide high reflectance and low group delay dispersion in the 355 - 455 nm range (see the table to the right and the Graphs tab for details). This wavelength range is centered about 400 nm, making the mirrors ideal for the second harmonic of femtosecond Ti:Sapphire lasers. Designed for use at a 45° angle of incidence, their low GDD of <|30 fs²| helps prevent broadening of the incident pulse.

The ultrafast mirrors are available in 1/2" and 1" diameters. The edge of each optic is engraved with the item number and an arrowhead pointing to the coated surface, as shown in the photos above. Please note that the fundamental of the Ti:Sapphire laser will leak through the mirror substrate; the back surface of these mirrors is polished so that an appropriate beam trap, such as the BT610 (BT610/M) Beam Trap, can be used to absorb this through beam. If you wish to keep the fundamental in the beam path, please consider our dual-band ultrafast mirror.

In addition to these mirrors for 355 - 445 nm, Thorlabs offers low GDD mirrors for various other wavelength ranges. For our full selection of optics for ultrafast applications, please see the Ultrafast Optics tab.

The plots below give the theoretically calculated reflectance and group delay dispersion (GDD) of these mirrors at a 45° AOI and represent the designed performance. The actual performance will vary from lot to lot within the specifications given in the Overview tab.

Click to Enlarge
Click for Raw Data for 300 - 1000 nm
The shaded region in this plot denotes the wavelength range over which we guarantee R_s > 99%.

Click to Enlarge
Click for Raw Data for 300 - 1000 nm
The shaded region in this plot denotes the wavelength range over which we guarantee <|30 fs²| GDD for s-polarized light. The GDD fluctuates rapidly outside of this wavelength range.

Click to Enlarge
The laser induced damage threshold (LIDT) value of an ultrafast optic is defined as the fluence (per pulse) that produces visible damage after a given number of pulses. These LIDT values were measured with 55 fs FWHM pulses at 400 nm that were s-polarized and incident at 45°.