Lasers

LASERs

4MW Q-Switched Nd:YAG Laser

D. Prutchi, “The Laser Billboard - A Low-Cost Laser Image Projection System”, CCI - The Computer Applications Journal, Issue #86, 28-35, September 1997. [PDF] [Software]

Recommended Books

2 Joule Nd:YAG Laser

15W CO2 Laser

2W CW Semiconductor Diode Laser

Image Intensifiers and Image Converters

Top Left: Home-made Gen III image intensifier scope

Top Right: Russian-made Gen I waterproof night vision scope

Bottom Left: Home-made far ultraviolet (UV) image converter scope

Middle Right: Infrared (IR) image conversion tube

Bottom Right: Russian Gen I image intensifier tube

Low-Cost Laser Graphics Projector

This is a simple implementation using the “SSY-1” - the Nd:YAG (neodymium yttrium aluminum garnet) laser transmitter of the AN/VVG-3 laser range finder that used to be part of the M1 Abrams Tank.

The AN/VVG-3 rangefinder was developed by Hughes. It consists of the pulsed Nd:YAG laser, a receiver and timing and logic electronics integrated into the tank's fire control system. The operator aims the rangefinder on the target and fires the laser. The laser beam is reflected back from the target into the receiver and the time of travel to and from the target provides an accurate range measurement for the fire control computer. The rangefinder has a laser firing rate of 1 shot per second and provides range accuracy to within 10m and target discrimination of 20m.

Click here for Samuel M. Goldwasser’s excellent page on the SSY-1

Robert Iannini’s book shows how to build your own high-power Nd:YAG laser.

This is a light spot-welding laser based on the “SSY-1”. I removed the Q-switch and use a boresighted He-Ne laser as a guide to where the Nd:YAG pulse will hit. The laser driver dumps up to 400J into the flashlamp (!!) to get a mere 2J output.

Robert Iannini’s book shows how to build your own high-power Nd:YAG laser.

This is a sealed-tube CO2 laser with an output power of around 15Watts. It needs a triggering voltage of at least 9.5kV and an operating current of 15mA. Cooling is through deionized water flowing at a rate of 1 liter/minute. The power supply is based on a neon transformer that is rectified and filtered. A ballast resistor of 100kOhm is placed in series between the tube and the power supply. I use it to cut thin balsa wood for models.

Robert Iannini’s book shows how to build your own CO2 laser.

This 2A constant-current supply is used to drive a high-power laser diode (circle at left). Diode lasers that operate between 0.6-1.0 µm produce low scatter, lower water absorption, low protein absorption, and high hemoglobin absorption. All of these factors make diode laser wavelengths useful for many medical applications. Laser output from this device demonstrates extremely rapid and efficient blood coagulation, which is probably due to the high hemoglobin absorption.

Robert Iannini’s book shows how to build your own high-power CW diode laser.

The infrared (IR) image converters are useful for looking at the beam produced by Nd:YAG lasers, IR CW and IR pulsed lasers. The ultraviolet (UV) image converter is used to look at the emission produced by nitrogen lasers. I use the image intensifiers as imaging detectors when working on single-photon quantum optics experiments.

Robert Iannini’s book shows how to build your own IR image converters.

Q-Switched Ruby Laser

This is a ruby laser engine that came from the M-60 Tank Rangefinder (AN/VVG-2). It produces a 50 mJ pulse when driven with around 100J. The Q-switch is a rotating prism driven at 30,000 rpm by a small DC motor. A magnetic pickup on the motor shaft supplies trigger signals for flashlamp trigger circuit. I am currently building a flash holography system based on this laser engine.

Robert Iannini’s book shows how to build your own high-power ruby laser.

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