Optical Reference Cavity




  • Laser Frequency Stabilization
  • Quantum Computing
  • Laser Cooling and Trapping
  • High Resolution Spectroscopy
Wavelength 1550 nm, 1397 nm, 1156 nm or 1064 nm
Finesse > 300 000 (1550,1397 & 1156 nm)
> 200 000 (1064 nm)
Cavity Length (ULE Spacer) 12.1 cm
Cavity Mirrors Crystalline Coating (xtal stableTM) on Fused Silica Substrate
Free Spectral Range 1.24 GHz
Windows AR Coated, Angled and Wedged
Thermal Shielding Active
Thermal Noise ADEV Limit 1.6 x 10-16
Linear Drift Rate ~ 150 mHz/s
Ambient Temperature Sensitivity ~ 4 mK/°C

Weight (incl. Temperature Controller

Vacuum Pump and Controller)

55 kg


The High Finesse Optical Reference Cavity with Crystalline Mirrors (XM-ORC) is borne out of the combined expertise of Menlo Systems (ultrastable laser systems and reference cavities) and Thorlabs (high performance optical components) and is the solution when customization and ultimate performance are paramount.

The Menlo Systems supplied Fabry-Pérot-type cavity comprises a cylindrical resonator spacer made out of ultra-low expansion glass (ULE) designed by the Physikalisch Technische Bundesanstalt (PTB) in Germany. The cavity is mounted horizontally on four support points within a sealed stainless steel vacuum housing and is engineered for exceptional temperature stability to enable low frequency drift. The compact design ensures minimal spatial demand and portability is ensured by a mechanical locking mechanism.

Thorlabs provides the cavity mirrors consisting of a substrate-transferred crystalline (xtal stable) coating on a fused silica substrate for maximum reduction in thermal noise and excellent optical performance. Note that each mirror is spatially mapped for optical losses to ensure the target finesse is realized.

Every system is baked-out during the assembly process and a vacuum pump and temperature controller are included. The addition of ULE thermal compensation rings (licensed from PTB) ensures that room temperature operation will roughly correspond to the zero crossing of the thermal expansion coefficient for the assembled cavity.

XM ORC Cylindric Cavity

Calculated thermal noise floor


Thermal noise ADEV limit
1.6 x 10-16


modallan ORS v2 20190129


PN ProfKatoriCavities v3 20190129 2

Menlo Expert Ben Sprenger 2019
Dr. Benjamin Sprenger
Your direct line to our expert

Data sheets

Product literature

Ordering information

  • Product Code
  • XM-ORC

+49 89 189166 0

Menlo Systems, Inc.
+1 973 300 4490

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