Photos of Zygo Helium-Neon Lasers

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Photos of Zygo Helium-Neon Lasers

These are various stabilized HeNe lasers from Zygo, a maker or interferometer-based metrology products and systems.

Like HP (now Agilent), Zygo also manufactures what is called a "Two-Frequency HeNe Laser" for use in their interferometry based measurement and calibration systems. All except the 7705 use an HeNe laser tube of conventional design with an AOM to generate the two frequencies exactly 20 MHz apart. (The 7705 uses Zeeman-split technology like the HP/Agilent lasers.) The Axiom 2/20 was the first of a series of lasers that evolved through the 7701 and then 7702. All three of these are functionally similar with minor changes in implementation between the Axiom 2/20 and 7701 - both of which use a discrete control PCB, followed by the 7702 with its firmware-based control PCB. Since the split/REF frequency is 20 MHz - much higher than any HP/Agilent laser - the Zygo laser rae not at all compatible with them electronically. But except for the higher frequency optical receiver, interferometer optics of Zygo systems are very similar. Much more information on these lasers can be found in the chapter: Commercial Stabilized HeNe Lasers of Sam's Laser FAQ.

Zygo Axiom 2/20 Helium-Neon Laser (Gallery)
The Axiom 2/20 was the first of the Zygo lasers to use an AOM to generate the 20 MHz "split" frequency of the two-frequency HeNe laser. It is functionally similar to the 7701 and 7702 but uses a different electrical connector on the back panel.
- View 01 - Left front view.
- View 02 - Front closeup view. The shutter selects the full beam, no beam, or a narrow alignment beam.
- View 03 - Right back view.
- View 04 - Back closeup view.
- View 05 - Left front interior view.
- View 06 - Left side interior view.
- View 07 - Right back interior view.
- View 08 - Right side interior view. be shielded.
- View 09 - AOM RF driver interior view.
Zygo 7701 Helium-Neon Laser (Gallery) The 7701 was the successor to the Axiom 2/20. While it is functionally similar, the electrical connector differs, and it uses an HeNe laser tube designed and built by or for Zygo.
- View 01 - Left front view.
- View 02 - Front closeup view. The shutter selects the full beam, no beam, or a narrow alignment beam.
- View 03 - Right back view.
- View 04 - Back closeup view.
- View 05 - Left front interior view.
- View 06 - Left side interior view.
- View 07 - Right back interior view.
- View 08 - Right side interior view. be shielded.
Zygo 7702 Helium-Neon Laser (Gallery)
The primary difference between the 7702 and 7701 is in the use of a microcontroller-based control PCB with a built-in AOM driver. Internally, everything else is pretty much the same and modern chassis include all mounting holes to be used for either laser. However, the 7702 has an RS232 interface for diagnostics and firmware updates, and a fiber-optic connector for the REF signal (in addition to the ECL REF signal).
- View 01 - Left front view.
- View 02 - Front closeup view. The shutter selects the full beam, no beam, or a narrow alignment beam.
- View 03 - Right back view.
- View 04 - Back closeup view.
- View 05 - Left front interior view.
- View 06 - Left side interior view.
- View 07 - Right back interior view.
- View 08 - Right side interior view.
Zygo 7705 Helium-Neon Laser (Gallery)
The 7705 is a Zeeman-split HeNe laser functionally similar to the HP/Agilent 5517D, but in a much smaller case - approximately 10x2.5x2.4 inches - even smaller than it appears in these photos. The actual laser tube, which is less than 4 inches in length, is custom made by or for Zygo.
- View 01 - Left front view.
- View 02 - Front closeup view. The shutter had positions only for open and closed, no alignment aperture.
- View 03 - Front plate closeup view.
- View 04 - Front interior closeup view.
- View 05 - Right back view.
- View 06 - Back closeup view. The DB9F is for power and LOCK status while REF is via the fiber-optic connector.
- View 07 - Back plate closeup plate view.
- View 08 - Back interior closeup view.
- View 09 - Laser assembly consisting of tube assembly and Heater Board.
- View 10 - Tube assembly top view. (The beam exits to the right.) Note all the locations for alignment set-screws and Loctite. :) The wide slot likely provides access to the waveplate adjustments.
- View 11 - Tube assembly bottom view. The cables (from left to right) are: photosensors, heater, temperature sensor thermistor, HeNe laser power supply DC input.
- View 12 - Closeup of back of laser tube assembly. The hole in the potted ballast resistor(s) is for the REF beam to exit to the fiber-optic connector.
- View 13 - Closeup view of front of laser tube assembly. The large collimating lens is the only thing really visible, but behind that are the expanding lens and waveplate(s).
- View 14 - Another angle of front of laser tube.
- View 15 - Voltex HeNe laser power supply brick.
- View 16 - Beam sampler.
- View 17 - Closeup of interior of beam sampler.
- View 18 - Potted ballast removed from cylinder.
- View 19 - View inside cylinder showing tube HR mirror, end of magnet, and red RTV globs securing tube assembly. :).
- View 20 - View 1 of waveplate assembly
- View 21 - View 2 of waveplate assembly
- View 22 - Back view of beam expander
- View 23 - Front fiew of beam expander
- View 24 - HeNe laser tube/magnet assembly
- View 25 - Tube with anode insulator and heater
- View 26 - Tube parts showing heater and insulators
- View 27 - Four section cylindrical Alnico magnet
- View 28 - Closeup of anode-end of tube
- View 29 - Closeup of cathode-end of tube
- View 30 - Naked tube next to AA cell for size comparison - battery not included. ;-)
- View 31 - Tube/optics assembly parts in approximately correct position relative to each-other.
- View 32 - Heater Board left view.
- View 33 - Heater Board Right view.
- View 34 - Closeup of Heater Board. Note the unpopulated position for U1, presumably some type of power device that isn't used. The only adjustment on the PCB is the trimpot (R43), possibly for the temperature set-point at which switchover from preheat to locking takes place.
Zygo 7712 Helium-Neon Laser (Gallery)
The 7712 is in a much higher quality sealed case and uses water cooling to achieve a long term stability about 10 times that of the 7701 or 7702. Its output power is also about double that of the 7701 or 7702. And there is an additional 42 MHz AOM to offset the output from the lasing frequency to miminize effects of back-reflections on laser stability. The microprocessor-based controller is packaged on two PCBs with an RS232 interface similar to that of the 7702.
- View 01 - Left front view.
- View 02 - Front closeup view. The shutter selects the full beam, no beam, or a narrow alignment beam.
- View 03 - Right back view.
- View 04 - Back closeup view.
- View 05 - Left back (underside) tube enclosure view.
- View 06 - Left (underside) tube enclosure view.
- View 07 - Interior showing optics and control PCBs.
- View 08 - NEOS AOM (or what's left of it).
- View 09 - Interior closeup.
- View 10 - Control PCBs sandwich closeup.
- View 11 - Interior with main parts labeled. (The HeNe laser tube is below.)

Photos of Zygo Helium-Neon Lasers

Zygo Axiom 2/20 Helium-Neon Laser

Zygo 7701 Helium-Neon Laser

Zygo 7702 Helium-Neon Laser

Zygo 7705 Helium-Neon Laser

Zygo 7712 Helium-Neon Laser