Combs are used as frequency reference when addressing narrow-line atomic or molecular transitions (laser cooling & quantum optics).
When the repetition rate of a fiber based comb is locked to Stabiλaser 1542, the comb lines inherit the narrow linewidth of the Stabiλaser 1542. Furthermore, the absolute frequencies of the comb lines are set by the accurate Stabiλaser 1542 frequency1.
The stabilized comb becomes the ideal tool for referencing laser sources used to address narrow-line transitions in atoms and molecules, e.g. the multiple laser sources used in typical laser cooling and quantum optics experiments.
アプリケション
- Optical frequency comb stabilization and line narrowing
- Dual comb spectroscopy
- Source for microtoroid frequency combs
- Calibration of telecom equipment (e.g. high resolution wavelength meters)
- Research in ultra high-speed communication (low-noise, low-drift source)
- Wavelength meter calibration
- Length metrology – interferometric length calibrations
- Source for certain quantum cryptography protocols
- Cavity ringdown spectroscopy
- Cavities used as frequency references in laser physics experiments
Dual comb spectroscopy
In Dual Comb Spectroscopy (DCS), the highest resolution and accuracy (~kHz level) is achieved, when the relative linewidth between the two combs is below ~1 kHz, and both combs are stabilized to an absolute frequency standard2. Both requirements are met with a Stabiλaser 1542 reference.
Telecom applications
| Acetylene line | wavelength fixed by acetylene line, preferred and widely accepted |
|---|---|
| calibration tool | wavelength meters and telecom systems |
| research | low-noise and low-drift ource |
| Compelling advantages | Industrial components used for extended use, long lifetime, and is a primary standard, no calibration required. |
Length metrology reference
| meter definition | The metre is the length of the path travelled by light in vacuum during a time interval of 1/299 792 458 of a second |
|---|---|
| Realizing the meter | Iodine stabilized He-Ne lasers. Stabiλaser 1542 with frequency doubler (option, or user added) |
| Advantages | Only one acetylene line within tuning range makes it impossible to lock on the wrong line. Fiber coupled output, industrial components allow for long life time. The Stabiλaser can be used directly, no need for a working standard laser for daily calibration work. |
| Example | *As an example, the Stabilaser 1542 may provide traceability for interferometric calibration of gauge blocks. |
System Layout
At the heart of the Stabiλaser 1542 is a compact ultra low-noise fiber laser stabilized to the acetylene 13C2H2 P(16) (ν1 + ν3) transition at λ = 1542.3837 nm, corresponding to the frequency f = c/λ = 194 369 569 384 kHz. The laser meets the conditions of the BIPM recommendation on standard frequencies and can be used as a primary standard with an uncertainty of 5 kHz. The proprietary optical design and control software ensure both autonomous operation and a high quality laser output. The Stabiλaser 1542 is available in a 19 inch chassis and is controlled by an external PC.
GUI
Intuitive software allows easy control by an external PC.
Long-term drift and accuracy
Relative slope α
α ≈ u(α) ≈ 1×10-12/year
Measured with reference to a GPS disciplined Rb clock. Short-term noise is due to the Rb clock. The average frequency f agrees with the CIPM recommendation for an acetylene stabilized laser.
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