Harmonic Beamsplitters with Low Dispersion for Ti:Sapphire Wavelengths

Specifications
Item #	UBS20	UBS21
Optic Shape	Round	Elliptical
Diameter	1" (25.4 mm)	Minor: 25.0 mm (0.98") Major: 44.2 mm (1.74")
Diameter Tolerance	+0.00/-0.20 mm	Minor: +0.00/-0.10 mm Major: N/A
Thickness	4.0 mm	2.0 mm
Thickness Tolerance	±0.4 mm	±0.10 mm
Reflectance	Rs > 98.5% (360 - 440 nm) Rp < 0.3% (700 - 900 nm)
Group Delay Dispersion (GDD)	|GDD| < 20 fs² (360 - 440 nm)
Transmission Range	700 - 900 nm
Angle of Incidence (AOI)	56°
Clear Aperture	>80% of Diameter
Surface Quality	20-10 Scratch-Dig
Surface Flatnessa	λ/10	2λ
Parallelism	N/A	≤5 arcsec
Substrate	UV Fused Silicab
Reflectance/Transmission (Raw Data)	Reflectance Transmission

• Specified Over Clear Aperture; Measured at 632 nm
• Click Link for Detailed Specifications on the Substrate

Features

• Beamsplitter for Second Harmonic of Ultrafast Ti:Sapphire Lasers
• R_s > 98.5% (360 - 440 nm); R_p < 0.3% (700 - 900 nm)
• Low Group Delay Dispersion (GDD): < 20 fs² from 360 nm to 440 nm
• UV Fused Silica Substrate with Beamsplitter Coating on Front Surface
• Round Format or Elliptical Format for Circular Aperture at 56° AOI

Thorlabs' Ultrafast Harmonic Beamsplitters, also known as harmonic separators, are designed to separate the fundamental and second harmonic of light from an ultrafast Ti:Sapphire laser. Each optic features a coating designed for high reflectance of s-polarized light in the 360 to 440 nm wavelength range and low reflectance of p-polarized light in the 700 to 900 nm wavelength range. The coating is designed for use at a 56° angle of incidence (AOI) to minimize the reflectance of the fundamental component. These beamsplitters are ideal for Ti:Sapphire femtosecond pulsed lasers where pulse broadening is a concern by offering less than 20 fs² absolute GDD.

The beamsplitter coating is applied to one surface of the UV fused silica substrate, while the other surface is uncoated. The edge of the round substrate (Item # UBS20) is engraved with the item # and an arrow indicating the coated side of the beamsplitter. The coated side of the elliptical variant (Item # UBS21) may be determined through visual inspection.

These beamsplitters are offered in round or elliptical variants. The elliptical substrate offers a larger clear aperture than the round substrate when mounted at 56° AOI. We recommend mounting Ø1" round beamsplitters in our POLARIS-B1G or POLARIS-B1S Polaris Mounts. For mounting 25 mm elliptical beamsplitters, we offer the BW25M Brewster's Angle Mount. Please refer to the photos below.

Thorlabs also offers a wide selection of ultrafast mirrors and beamsplitters. Additionally, we offer harmonic beamsplitters for Nd:YAG applications.

Click to Enlarge

View Imperial Product List

Item #	Qty	Description
POLARIS-B1S	1	Polaris Ø1" Flexure-Clamp Fixed Mount, Optimized for Beamsplitters
UBS20	1	Ø1" Round Low-GDD Beamsplitter for Second Harmonic of Ultrafast Ti:Sapphire Lasers
POLARIS-CA1	1	Flexure Clamping Arm for Ø1" Posts, Non-Bridging, Stainless Steel, 1/4"-20 Clamping Screw
PLS-P1	1	Ø1" Post for Polaris Mirror Mounts, One 8-32 Tap, L = 1.00"
Add To CartExportForward

View Metric Product List

Item #	Qty	Description
POLARIS-B1S	1	Polaris­™ Ø1" Flexure-Clamped Fixed Mount, Optimized for Beamsplitters
UBS20	1	Ø1" Round Low-GDD Beamsplitter for Second Harmonic of Ultrafast Ti:Sapphire Lasers
PLS-P246/M	1	Ø25 mm Post for Polaris Mirror Mounts, One M4 Tap, L = 24.6 mm
POLARIS-CA25/M	1	Flexure Clamping Arm for Ø25 mm Posts, Non-Bridging, Stainless Steel, M6 Clamping Screw
Add To CartExportForward

UBS20 Round Beamsplitter in a
POLARIS-B1S Flexure-Clamp Mount

Click to Enlarge
UBS21 Elliptical Beamsplitter in a
BW25M Brewster's Angle Mount

Click to Enlarge

Click to Enlarge

Click here for raw data.
This data was taken at a 56° angle of incidence. Values are typical and will vary from lot to lot.
The blue shaded regions denote the wavelength ranges over which the reflectance is specified.