Melles Griot HeNe Laser

And Other Optical Parts

This unit is a gold-mine of parts for the laser experimenter, incorporating a laser and power supply, a rotating scanning system, several first-surface mirrors, a high sensitivity photo-diode and many other useful parts.

 

The Laser

Laser Specifications:

  • Melles Griot Helium Neon

  • Power: typical 1mW, min 0.5mW
    (Class 2A)

  • Wavelength 632.8nM

  • Power Supply Module:
       Input: 24V d.c.
       Output: 1.8KV 4mA (regulated)

 

Helium neon laser and HT power unit.

Laser operates with the following voltages applied:

  • Red:  +24V

  • Black:  0V

  • Orange:  0V (enable)

  • Yellow:  N/C

 

The 1mW laser is a surprisingly powerful light source.

(Beam is made visible by dust in the air)

Close-up of the operating laser.

(Beam is made visible by dust in the air)
Beam Quality

Diffraction rings around a central spot are visible in this deliberately over-exposed photograph.  The rings are clearly visible to the naked eye and are not an artifact of the camera lens.  The laser was positioned 10 meters from the screen.  The central "dot" is approximately 15mm diameter.

These rings are a demonstration of the superb optical quality of the beam.  Diode lasers rarely have the beam quality required to do this, due mainly to the poor quality of the collimation lenses in common use.

 

With care, helium neon lasers can be used for holographic experiments.  The high beam quality and single-line output spectrum are necessary parameters for this application.  Diode lasers are not usually suitable for the production of holograms.

 

The Optical Parts

Assorted Optical Parts:

  • First-surface mirrors: five flat
    (one on adjustable mounting)

  • First-surface dichroic mirrors: one flat and one concave.

  • Lens: red for focusing a hene beam

  • Beam collimator

 

Assorted optical parts, seen in more detail below

View high-resolution image

Two first-surface flat mirrors, the one on the right has an adjustable mounting.

One of three more mounted first-surface flat mirrors

A concave, dichroic first-surface mirror.  Designed to focus the hene beam while allowing unwanted wavelengths to pass through.

Another view of the dichroic concave mirror showing the focusing effect.  (colour is NOT false)

A flat, dichroic first-surface mirror in a fixed mounting

A red filtered convex focusing lens

The beam collimator lens assembly.

 

The Scan Motor, CPU and PSU

Scan System:

  • Line-scan: Pentagonal rotating mirror

  • Compound scan: 3-axis deflection

 

Motor Assembly:

  • 15V d.c. powered

  • Brushless multipole design

  • 600KHz resonator controlled clock

 

CPU Card:

  • Hitachi 63C09

  • 27C512 EPROM

  • 40MHz clock module

  • HP 4502 opto-isolators

 

PSU:

  • Power input:  220-240V AC

  • Outputs:  +5V, +12V, -12V, +15V, +26V

  • Style: Custom, open frame module

 

Line-scan motor with pentagonal mirror
 

Underside of line-scan motor showing control electronics

The CPU card

The photodiode which is located on the CPU card

This is the system PSU.  An off-line switched-mode unit with multiple outputs.

 

The Complete Scanner Unit

Scanner Specifications:

  • Scan system: multi-axis laser

  • Laser type: Helium Neon (HeNe)

  • Computer Interface: **not known

  • Supply: 220-240V 50Hz, 35W max.

  • Dimensions: 300 x 220 x 80mm

  • Weight: 5.0Kg

** If you can help with more detailed specifications, please send us an email!

 

Please note that we do not test the operation of these scanners, we test only the laser.  A functional scanner may be made to operate in "stand alone" mode by setting the rear panel DIP switches as follows:

  • SW1 (upper bank) all ON apart from number 2

  • SW2 (lower bank) all OFF apart from numbers 3 & 4

 

View with covers in place.

Internal view - see high resolution image

 

 

For quotation, please use ref: ICL SCANNER

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