Nikon NKL-85 Helium-Neon Laser (Gallery)
The Nikon NKL-85 consists of a laser head and separate controller and
is probably a Lamb-Dip stabilized HeNe laser similar in
its principles of operation to those of the Spectra-Physics 119. I do not know
the manufacturing date precisely, but there was a 1981 date code on a
TTL IC in the controller, which makes it substantially newer than
the SP-119. Much more information on these lasers can be found in the chapter:
Commercial Stabilized HeNe Lasers
of Sam's Laser FAQ.
View 01 - Left front view of laser head.
I believe that there are supposed to be
three adjustable feet, but I don't have them. There are also no safety
stickers, though I suppose it's possible they fell off. This laser is
HEAVY - at least 15 pounds, with most of that in the baseplate and cover,
and massive laser resonator frame.
View 02 - Front interior view of laser head.
The black cover simply conceals another
semi-transparent plastic cover. It's hard to tell if that holds the OC
mirror or is simply protection. The two ballast resistors can be seen
standing up on the right.
View 03 - Right back view of laser head.
All power and signals enter via the 27
pin military-style round connector except for one input to the mini-coax
above it. That goes to what is probably an amplifier whose output
connects to a pin on the round connector. The only wiring to that
circuitry is DC power - nothing else inside the laser head.
View 04 - Back interior view of laser head.
The two (2) redundant micro-switches
for the cover interlock are visible at the lower left.
View 05 - Left front interior view of laser head.
The sheet metal cover for the PZT
power supply has been removed for the photo. The glass bulb with the
large gas reservoir and cathode of the HeNe laser tube is at the top,
with a perfect silvery/dark getter spot. The bore of the tube is totally
concealed below within a metal enclosure, probably for both mechanical
support, and thermal and/or magnetic isolation.
View 06 - Right back interior view of laser head.
The metal covers for the HeNe
laser power supply has been removed for the photo. The circular black cover
conceals the photodiode preamp PCB (which uses an IC in a TO5 can).
There is only a single photodiode monitoring the waste beam from the
laser tube. The box above the connector contains some additional
circuitry, purpose unknown.
View 07 - Left side interior view of laser head.
This shows the PZT power supply
which includes a 7404 TTL hex inverter (just visible at the upper
right) probably configured as an oscillator driving transistors (not
vacuum tubes, can you believe it?!!!). The inverter transformer is
in the metal case and the voltage multiplier is on the left.
View 08 - Right side interior view of laser head.
This shows the HeNe laser power
supply which is also a transistor-based inverter. The inverter transformer
is in the metal case and the voltage multiplier is on the right.
View 09 - Laser tube powered. My digital camera does a terrible job of
rendering HeNe laser bore discharges but it really is perfect. :)
View 10 - Label on laser head. I doubt 24041 of these were built, so
that's probably number 41. :) There were no safety labels on this laser
head, but I suppose they could have fallen off.
View 11 - Front view of controller with cover removed. (The cover
is just boring sheet metal!) Since both the HeNe laser power supply
and PZT power supply are in the laser head, everything inside the
controller is low voltage.
View 12 - Back view of controller with cover removed.
View 13 - Closeup view of controller front panel. There isn't much
in the way of user controls or indicators. My guess is that after a
suitably long warmup period, the "INCREASE" and "DECREASE" buttons are
used to vary the PZT voltage to locate the center of the Lamb Dip
by monitoring the laser output power, and then the switch above
"SELECT" is flipped to the "LOCK" position.
View 14 - Closeup view controller back panel.
View 15 - Closeup view of controller interior.
View 16 - Closeup view of controller printed circuit board.
View 17 - Closeup view of controller hour meter showing near zero
hours. Based on the wiring, I believe it is supposed to be upside-down
with respect to the other components on the PCB.
View 18 - Label on controller. This controller was acquired from a
totally different source than the laser head. But note that the "No"
matches. I do not know if this is a serial number or part number though.