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Dichroic Atomic Vapor Spectroscopy Kit


Dichroic Atomic Vapor Spectroscopy Kit

  • Ideal for Lasers Locking Tunable or Teaching Labs
  • Rubidium or Potassium Vapor Cells Available Separately


  • Dichroic Atomic Vapor Spectroscopy (DAVS) for Locking to Transitions
  • Rubidium, Potassium, and Custom Vapor Cells Available
  • PM Fiber-Coupled Setup
  • Ideal for Locking Tunable Lasers or Teaching Labs

The Thorlabs SKDAV kit consists of a proven set of components to construct a compact, fiber-coupled dichroic atomic vapor spectroscopy (DAVS) setup. It offers a method for producing a highly stable lock for tunable lasers, with a wide capture range, low power requirements, and steep signal slope. The kit also allows for the study of the Zeeman effect in atomic transitions.

The kit has been designed using stock optics and mechanics as well as compatible custom components, making it compatible with other Thorlabs cage system and lens tube components. For a list of the major components and subsystems included in the DAVS kit, please see the Kit Contents tab.

While the vapor cell heater is included in the kit, please note that the vapor cell and temperature controller must be purchased separately. Currently, we offer rubidium and potassium reference vapor cells, which are available below. A variety of custom vapor cells are also available; please contact applications@thorlabs.com for more details. Thorlabs' TC200 Temperature Controller is compatible with the cell heater.

Dichroic Atomic Vapor Spectroscopy
Dichroic Atomic Vapor Spectroscopy (DAVS) utilizes the Zeeman effect to create a signal suitable for laser locking. A rubidium vapor cell is placed in a weak longitudinal magnetic field. The Zeeman splitting of the atomic transitions allows for wavelength locking at locations off of resonance peaks. For a detailed tutorial on DAVS, please see the DAV Spectroscopy tab.

Custom Options and Assembly Services
Our spectroscopy kits are adaptable to most tunable lasers with user-supplied feedback mechanisms. While our standard kit is designed to accept PM fiber-coupled sources, we can also offer kits for free-space input. We can also offer assembly services upon request.

Long-Term Stability  
Required Input Power ~100 µW
Input Fiber Termination* FC/PC
Wide Capture Range ~500 MHz
Detector Bandwidth 1 MHz
Detector Output Range ±10 V
Reference Cell Temperature 50 °C (Max)

*Alternate fiber inputs are available.Please contact us.



DAVS Kit Contents

Thorlabs' DAVS Kit contains the following subsystems:

  • Fiber Input and Polarizer
  • Vapor Cell Heater and Magnets
  • Output Prism
  • Mirrors and Balanced Detector

Fiber Input and Polarizer

The fiber input is designed with our F220FC-780 fiber collimator and cage system components. The F220FC-780 collimates the input from an FC/PC-terminated PM fiber, which must be purchased separately. For Rubidium, we recommend using our P1-780PM-FC-5 patch cable. 

Once the light is collimated, the beam passes through a calcite Glan-Laser polarizer to ensure polarization purity. Both the fiber collimator and polarizer are provided with our cage system mounts, which easily allows for the user to add other components using our 30 mm cage system.


Vapor Cell Heater and Magnets

This assembly consists of our GCH25-75 vapor cell heater and a permanent magnet assembly specifically designed for the DAVS kit. Both magnets feature a hole in the center to allow the light to pass, and they attach to the gas cell heater using cage system ER rods included with the heater. The magnets are easily removed so that both absorption and DAV spectra may be measured.

Please note that neither vapor cells nor a temperature controller for the GCH25-75 are included with the SKDAV. Rubidium and Potassium cells are available on the bottom of this page, and other atomic vapor cells are available upon request. Thorlabs offers the TC200 temperature controller which is compatible with the vapor cell heater.


Output Prism

After exiting the vapor cell and magnet assembly, the light will consist of two counter-rotating circular polarizations, which will be absorbed at either red- or blue-shifted frequencies (see the DAV Spectroscopy Tab for details). A zero-order quarter-wave plate (WPQ05M-780) will map the circular polarizations onto orthogonal linear polarizations. These linear polarizations are then split by a Wollaston Prism (WP10-B) at an angle of 20°.

Both polarization optics are mounted into 30 mm cage system rotation mounts (the quarter-wave plate is mounted into a CRM1P while the prism is mounted using a CRM1. The CRM1P features a micrometer that allows for very small adjustments of the wave plate, which in turn leads to finer adjustments of the locking frequency. The use of these cage system and SM1 lens tube mounts would allow easy addition of additional optics or mechanical components according to experimental needs.


Mirrors and Balanced Detector

A square folding mirror and kinematic mirror mount are included to direct the output of the Wollaston prism so that the assembly can be made more compact. If space is not an issue, this mirror can be left out of the system. After reflecting off of the square mirror, the two orthogonal polarizations are reflected separately by Ø1/2" mirrors, so that the beams can be aligned with the two inputs of our PDB210A balanced detector. The image to the right shows the beam path through the entire system, which illustrates the function of the mirrors. The balanced detector allows for measurement of three output voltages: the separate signals recorded from each photodiode, as well as the difference between the two measurement channels. This difference channel provides the DAVS signal, which can be used for a stable laser lock. The other two chanels are useful for alignment of the system, as well as to illustrate the principles of DAVS in teaching labs.


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