ORS-Cavity Standalone Reference Cavities
Ultrastable Laser

ORS Cavity 3w


Advanced Features and Benefits

  • Compact footprint
  • Tailored to customer needs
  • Stable reference for high-end experimental setups
  • Transportable
  ORS-Cubic-Cavity ORS-Cavity

500 - 1600 nm (IBS),

900 - 5000 nm (XTAL)

500 - 1600 nm (IBS),

900 - 5000 nm (XTAL)

Finesse ≈250 000 ≈250 000
Cavity length 5 cm 12.1 cm
Free spectral range 3 GHz 1.24 GHz
Windows AR coated, angled and wedged AR coated, angled and wedged
Temperature of minimal thermal expansion between 20 and 35 °C between 20 and 35 °C
Thermal shields active and passive active
Ambient temperature sensitivity ~ 4 mK/°C ~ 4 mK/°C
Temperature sensor 10 kΩ NTC 10 kΩ NTC
Peltier elements 2x 25 W 1x 56 W
Ion getter pump 5 l/s 10 l/s
Achievable pressure < 10-7 mbar < 10-7 mbar
Stainless steel valve Cu sealed, KF flange Cu sealed, CF flange
Dimensions W 28 cm, L 28 cm, H 18 cm W 48 cm, L 35 cm, H 35 cm
Vacuum chamber material Al stainless steel
Mass 15 kg 55 kg


High finesse Fabry-Pérot cavities, with or without vacuum chambers, for ultra-stable laser systems. The resonator spacer is made out of ultra-low expansion (ULE) glass. The mirror substrates can be ULE or fused silica (FS), while the mirror coatings are either standard ion-beam sputtering (IBS) or low thermal noise crystalline (XTAL) coatings. Menlo Systems is the exclusive distributor of optically contacted cavities with mirrors based on Thorlabs Crystalline Solutions’ technology. The compact design of the vacuum chamber minimizes experimental setup spatial demands while delivering state-of-the-art laser linewidth and stability. The ORS-Cubic-Cavity variant is based on the rigidly mounted 5 cm cubic cavity (3 GHz FSR, licensed NPL patented technology). The rigid mounting of the cubic cavity allows for the transportation of the cavity enclosure without the need for realignment. A PTB designed ORS-Cavity is based on a 12.1 cm cylindrical spacer (1.24 GHz FSR). A transportation locking mechanism enables fast installation after delivery, without the need for realignment. Access to the built in thermistor and Peltier elements is enabled via vacuum feedthroughs.


  • Doppler cancellation system

    Product Code: ORS-Doppler

    For long distance transmission of sub-Hz linewidth through optical fibers (over 5 or 10 m) we recommend active phase noise compensation of the ORS Output. This involves measuring the phase noise induced by temperature variations and vibrations in the fiber through a back-reflection, and actively compensates this with a phase-locked loop.

  • Frequency shifting AOM

    Product Code: ORS-Frequency Shift

    The ORS can be tuned over tens of picometers in steps of the free-spectral-range. To reach a specific frequency in-between these steps (e.g. the Strontium transition at 698 nm), an additional noise-free frequency shift is required using acousto-optic modulators. ORS-Frequency Shift provides the precise output at the desired frequency for the ORS.

  • Frequency doubling

    Product Code: ORS-SHG

    It can be advantageous to lock the CW at half the frequency of the desired output, and add second harmonic generation (e.g. 1397 nm for the Strontium clock transition, with SHG to 698 nm). Frequency doubling can be integrated into your ORS system with free-space or fiber-coupled output.

Stability and Phase Noise


Thermal noise ADEV limit
5 cm CUBIC
1.4 x 10-15 9 x 10-16 4 x 10-16
Thermal noise ADEV limit
5.8 x 10-16 3.8 x 10-16 1.6 x 10-16


modallan ORS v2 20190129


PN ProfKatoriCavities v3 20190129 2

Menlo Expert Sandra de Vega 2021
Dr. Sandra de Vega
Your direct line to our expert

Data sheets

Ordering information

  • Product Code
  • ORS-Cavity Standalone Reference Cavities

+49 89 189166 0

Menlo Systems, Inc.
+1 973 300 4490

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