Precision Electro-Optic and Laser Technologies

D2-210 Spectroscopy Module

D2-210 spectroscopy module top view

The D2-210 Saturated Absorption Spectroscopy Module is an integral piece of our complete line of photonics tools supporting the AMO Community.


  • Configurable for Potassium, Rubidium, or Cesium
  • Side or Peak Locking
  • Temperature stabilized
  • Intensity normalized
  • Magnetic shielding
  • Terminal or pass-through configuration
  • Improved mechanics
  • Optional Doppler subtraction and fiber coupling
  • 5 MHz loop bandwidth

Saturated Absorption High-Precision Frequency Reference

Vescent Photonics’ D2-210 second-generation Spectroscopy Module makes locking to atomic transitions easier and more powerful than ever before. Completely redesigned to maximize performance in a number of laser-locking environments, the D2-210 makes atomic absorption-referenced frequency locks simple. Designed to work as a general-purpose frequency discriminator, it is compatible with our D2-125 Reconfigurable Servo as well as other feedback loop filters.The D2-210 can be charged with either Potassium, Rubidium, or Cesium. It is magnetically shielded to reduce perturbations due to magnetic fields and accommodates free-space or, optionally, fiber-coupled input. The D2-210 allows flexible operation, accepting laser powers from microwatts to over a hundred milliwatts, and it also offers improved, easier-to-align optomechanics and a beam path that effectively eliminates back reflections to the laser. The D2-210 provides a signal to lock to either the side of an absorption or the peak and can optionally support Doppler-broadened background subtraction.

View a typical configuration of a D2-125 servoing a D2-100-DBR laser.
Fill Choices K, Rb, Cs
Coupling Configuration Terminal or pass-through
Input power range1 2-1,000 mW
Input type Free-space or Fiber-coupled2
Supported locks Side-of-transition, peak
Gas Cell Temperature ~35 oC
Temperature Stability ~0.01 oC
Beam Height 0.95 inches
Package Dimensions 3.62 × 4.98 × 1.7 inches
Photodiode Amplifier
Transimpedance (signal) 20,000 Ω
Bandwidth (signal) 5 MHz
Noise @ 4 MHz (shot level) 80 nV/√ Hz
Power Cable Order VPN00410 Hirose-to-D Sub 9-pin when powered by D2-005
Order VPN00475 Hirose-to-Hirose when powerd by ICE-Box

All specification subject to change without notice.
1For best results.  As little as 500 µW will produce usable signals.