Low GDD Ultrafast Mirrors for 1400 nm - 1700 nm

  • Ultrafast Mirror for 1400 - 1700 nm
  • Group Delay Dispersion <30 fs2
  • Ideal for Telecom Applications



Application Idea

UM10-45C in an H45
45º Mirror Mount

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Item # UM05-45C UM10-45C
Design Wavelength Range 1400 - 1700 nm
Diameter 1/2" (12.7 mm) 1" (25.4 mm)
Diameter Tolerance +0.00 / -0.10 mm
Thickness 6.4 mm (0.25") 9.5 mm (0.37")
Thickness Tolerance ±0.20 mm
Clear Aperture >80% of Diameter
Reflectance Rs > 99% (1400 - 1700 nm)
Rp > 99% (1500 - 1600 nm)
Angle of Incidence 45°
Group Delay Dispersion |GDDs| < 30 fs² (1400 - 1700 nm)
|GDDp| < 30 fs² (1500 - 1600 nm)
Substrate Fused Silica
Front Surface Flatness λ/4 at 632.8 nm
Over Clear Aperture
λ/8 at 632.8 nm
Over Clear Aperture
Front Surface Quality 15-5 Scratch-Dig
Parallelism ≤3 arcmin
Back Surface Polished


  • Low Group Delay Dispersion: |GDD| < 30 fs2
  • Ideal for Pulses Shorter than 250 fs
  • Reflectance Greater than 99%
  • Ø1/2" and Ø1.00" Mirrors Available
  • Polished Back Surface
  • Surface Quality: 15-5 Scratch-Dig

Thorlabs' Low Group Delay Dispersion (GDD) Mirrors incorporate a coating offering high reflectance in the 1400 nm - 1700 nm wavelength range and are meant to be used at a 45° angle of incidence. These ultrafast mirrors are designed for use with erbium lasers (1530 - 1620 nm); however, the operating wavelength range also covers many of the major telecom bands, including E (1360 - 1460 nm), S (1460 - 1530 nm), C (1530 - 1565 nm), L (1565 - 1625 nm), and U (1625 - 1675 nm). These mirrors are ideal for applications where pulse broadening is a concern. They offer an ideal combination of greater than 99% reflectance and less than |30 fs2| GDD; for details, please see the Graphs tab.

These low GDD mirrors are available with either a 1/2" or 1.00" diameter. The edge of each optic is engraved with the item number and an arrowhead pointing to the coated surface. The back surface of these mirrors is polished so that the small percentage of light that leaks through the reflective coating may be used for applications such as power monitoring.

In addition to the low GDD mirrors here, Thorlabs also 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 graphs below are theoretical results of the reflectance and the group delay dispersion and represent the designed coating performance. Both plots are shown for an AOI of 45°.

Click to Enlarge

Click for Raw Data
The shaded region represents the specified wavelength range where RS>99%.
Click to Enlarge

Click for Raw Data
The shaded region represents the specified wavelength range where S-Polarization GDD<|30 fs2|. The GDD values fluctuate rapidly outside of the design wavelength range.

Posted Comments:
Kevin Lehmann  (posted 2019-04-26 15:17:46.823)
I would like to know what the reflectivity and GVD curves look-like for the UM10-45C mirror at normal incidence. Also, I would like to know if you provide this coating on concave mirror substrates.
asundararaj  (posted 2019-05-01 04:58:36.0)
Thank you for contacting Thorlabs. While data at normal incidence would not be possible, we should be able to obtain data close to normal incidence. We will contact you directly about this data and to discuss possible custom options.

Thorlabs offers a wide selection of optics optimized for use with femtosecond and picosecond laser pulses. Please see below for more information.

Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
UM05-45C Support Documentation
UM05-45CØ1/2" Low GDD Ultrafast Mirror, 1400 nm - 1700 nm, 45° AOI
UM10-45C Support Documentation
UM10-45CØ1" Low GDD Ultrafast Mirror, 1400 nm - 1700 nm, 45° AOI