Beam Expanders for Tunable Laser Sources


Optimized at a wide range of wavelengths for maximum flexibility, TECHSPEC DA (Divergent Adjustable) Fixed Broadband Beam Expanders are ideal for use with demanding tunable laser sources. They feature a 1940 nm design wavelength to compliment lasers with wavelengths from 1900-2100 nm, which are ideal for highly precise applications including medical surgery and plastic processing because of their unique absorption characteristics and ability to create very small and precise cuts in both biological tissue and plastics with minimal localized heating.


The beam expanders are available in high and low-power models with 2X and 3X magnifications. Low-power models feature standard 7980 Fused Silica while high power models feature 7979 Fused Silica substrates to ensure minimal IR absorption within the substrate. A threaded barrel divergence adjustment compensates for input beam divergence. These beam expanders are coated for 1940 – 2100 nm performance. They are easily integrated into prototype and advanced applications and maintain the highest quality across the adjustment range. TECHSPEC DA Fixed Broadband Beam Expanders are ideally suited for medical laser applications using highly tunable Thulium and Holmium sources.


TECHSPEC DA Broadband Beam Expanders offer λ/10 transmitted wavefront error and are manufactured using a fused silica substrate with excellent optical and thermal performance and stability. These optics feature broadband anti-reflection and laser line V-coatings for transmission >99%. RoHS Compliant TECHSPEC DA Broadband Beam Expanders are in-stock and available for immediate delivery.


Design Wavelength DWL (nm): 1940

Wavelength Range (nm): 1900 - 2100

Entrance Aperture (mm): 10.00

Exit Aperture (mm): 23.00

Transmitted Wavefront, P-V: <λ/10 for 5.5mm input beam (nominal, λ = DWL)

Mounting Threads:

  • Input: Male M30 x 1 
  • Output: Female M27 x 0.5

Housing Diameter (mm): 29.95

Angle of Incidence (°): 0.00

Coating: BBAR (1900-2100nm) & Laser V-Coat (1940-1950nm)

Transmission (%): >99 (nominal)

Coating Specification:

  • Ravg <0.1% @ 1940nm - 1950nm 
  • Ravg <0.5% @ 1900nm - 2100nm 
  • Ravg <0.25% @ 2000nm - 2100nm

Style: Fixed Magnification

Type: Beam Expander

Divergence Adjustment: Rotating Optics



  • Broadband Designs for Tunable Lasers
  • λ/10 Transmitted Wavefront Error
  • Threaded Barrel Divergence Adjustment to Compensate for Input Beam Divergence
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