Professor Mark Csele

Adventures In Science

The science center had given me an interest in lasers which, more than anything else, fuelled my drive towards studies in physics and engineering. As a kid, and even now, I was never sure whether I should go into physics or engineering – as it ends up, I did both. Not sure I’ll ever decide which is more interesting and certainly in the science center in the early 70’s I found both fascinating. Lasers (physics) were really neat but so was the machine that said ‘COFFEE’ (engineering) and the big PDP-11 computer running the tic-tac-toe game in the center of the place. Hmmmm … decisions, decisions …

My interest in “pure” science developed in parallel to my interest in electronics. Like I mentioned above, I was always fascinated with optoelectronic devices making the bridge between the two subjects. Our family made annual trips to the CNE (Canadian National Exhibition) in Toronto and one stop was always at the Edmund Scientific (now Eftonscience) booth. I’d always pick-up science trinkets, lenses, and prisms. As a (young) kid, I’d put a prism into the path of a sunbeam coming through the front window and marvel at the intense colours in the spectrum. It was little inspirations like this that drew me into the field of science, as well as those frequent trips to the science center.

I had dabbled into building odd science projects: I had attempted (with no design and almost no concept of the theory required) to build a carbon-dioxide laser from a Pringles chip can … oddly is did not work ;). Science looked like fun, but I didn’t really have the background at all.

Now, one of this main vehicles that drove me into science was participation in science fairs starting in grade 7.

My older brother had entered a few science fairs in the past and, visiting him while he setup his project, I was intrigued to say the least. I recall being attracted to a project in which the students built their own electron microscope using a long glass tube, external magnets, and a television screen as the output (with the electron gun removed). At the time, I did not recognize it as a variation on the Amateur Scientist design but I was totally fascinated by it.

It was 1979, grade seven for me, and a science fair was looming at school. My interests, at the time, were primarily in electronics and reading through the Edmund Scientific catalog I was interested in building my own GSR (Galvanic Skin Response) meter – primarily as a lie detector. The electronics were simple enough: a basic transformer power supply (built in a wooden box) and an old (round-style) sensitive microamp meter (courtesy, along with a huge amount of other old electronics and magazines, of a cousin in Buffalo, NY). The basic unit worked but to really make it interesting I wanted a strip-chart recorder! Dad built the basic wood box and installed a slow motor and paper roll and I built the electronics which consisted of a single power transistor as well as a pen mechanism which consisted of an old relay removed from a pinball machine. When the resistance (GSR) of the subject fell below a preset value the pen moved. The entire project, along with the recorder and the backboard, can be seen here in one of the few photos I could find of the project (an old Polaroid instant photo).

While the project looked really neat (featuring glass jewel indicator lamps from the 50’s), the actual science involved was thin at best – but back then for me it was all about ‘BUILD IT’. Using plants as subjects (another idea from that old Edmund Scientific catalog I had mentioned at the beginning of this page) I found that talking to these plants made them respond. My conclusion: plants have nerves (! ouch !) … Didn’t even consider that the carbon-dioxide from a person’s breath might have had something to do with the response. Suffice it to say that while the project looked impressive enough (lots of lights on the front panel and the moving pen was interesting to watch) it didn’t do well at the fair. ‘Build and show’ is one thing at a science fair but if the real science is missing, so is the point. Regardless, I _learned_ by looking at other projects and so an important purpose was served! Failure isn’t failure at all if one learns from one’s mistakes.

Grade eight and I needed (OK, Wanted) another project. In the back of an electronics magazine I found an ad for plans (the company was ‘Information Unlimited’ as I recall) for a number of interesting devices including a small Tesla coil and a ‘Sound Telescope’. Dad ordered both sets of plans and the sound telescope looked quite neat – picture a series of tubes, each resonant at different sound frequencies, with a sensitive amplifier and headphones. Mounted on a shoulder-mount (and looking a bit like a rocket launcher) we built it from a load of CPVC plastic tubes (the white, rigid type used for water, at a cost of $30 for all the tubes). A microphone from Olson electronics picked-up the sound which was fed to an amplifier scavenged from an old portable reel-to-reel tape recorder (bought at a garage sale for a few dollars) and was made even more sensitive by adding a homebuilt preamplifier between the the microphone and the amplifier (using one transistor – a design I used for a “linear power booster” for my guitar which served as a preamp). I built the amplifiers into a small plastic box from Radio Shack and powered it from two 9V batteries. The machine worked, and was amazingly directional. It won a few small awards at the fair including an honourable mention from the Youth Science Foundation and a bronze medal award from the US Army which was usually reserved for senior students (I was, apparently, the first junior ever to receive it). The science was certainly better (at least there was a tangible principle here) and winning an award, especially a bronze medal, certainly encouraged me to continue. (That bronze medal is still among my most cherished awards)

One of my biggest limitations might well have been access to information. Unlike today, where the internet has led to drastic changes in the way information is available, I was restricted to a large degree to magazines (electronics was a popular hobby back then so there were a number of periodicals available), the public library (where I had to manually search through old Scientific American articles from the stacks), catalogs (great for ideas), and old magazines like a 1968 copy of ‘Science Experimenter’ which featured a host of neat projects (a Tesla coils, a Van De Graaff generator), almost all geared to science fair projects. With electronics still a popular hobby, there were, at least, a number of decent electronics and surplus stores within a few hours drive. As a kid, one of our favourite shops was Olson electronics in Buffalo where we’d always pick-up a surprise pack of assorted electronic items for dirt cheap. Later, Active Surplus in Toronto became a favourite.

When I was in grade eight my parents bought me my first real laser. Indeed, I was fascinated by lasers since I’d seen them at the Science Center but to actually own one was almost unthinkable, and here was one available and almost affordable! The laser, purchased from Arkon Electronics (on Queen St. in Toronto and long since out of business) was a soft-sealed glass HeNe tube and a power supply kit consisting of a bag of parts and a photocopied schematic. The kit was simply listed in their advertisement in Electronics Todaymagazine as “HENE Laser Kit $149.95” (That seemed like an awfully large sum of money back then, but I sooooo wanted one – owning a laser was like owning one’s own interstellar spacecraft :). I built the laser in a day, the power supply on a piece of perfboard, and Dad built a wooden box to house the tube. I used the laser for countless experiments in the two years it lasted before gassing-out (Old laser tubes, being soft-sealed, had particularly short lives). The night I got it working I was already experimenting with mirrors and making a laser light show – all to the tune ‘Another One Bites the Dust’ as I recall (funny the odd things you remember 😉 – it was probably a first attempt to build a laser show like I’d seen at the CNE in Toronto. This new ‘toy’ was fascinating and it was amazing what happened when you put things like ornamental plastic in front: interference patterns galore!

Seen here in the wooden box, the tube was mounted in three ‘cradles’ lined with foam. The output apeture was a modified RCA audio connector with the center terminal removed – mating fiber optics could be made cheaply with RCA plugs. A teacher provided me with a piece of fiber optics to experiment with.

In grade nine I used this laser to build a light communications system for a science fair project in the local Niagara Regional Science and Engineering Fair. That project won me a trip to the Canada Wide Science Fair (CWSF) in Waterloo, Ontario (where I later studied). The project started as a laser-light show and ended-up as a full-fledged communications system. The trip to the CWSF was important to me personally as it showed me how to do research and allowed me to network with others. I got a taste of dorm life, had tours of labs at the University (which included seeing a massive argon laser), and had fun in general (they had PET computers at the dorms to play games, and a room full of the latest video games including ‘Elevator Action’ for which I built a MAME machine years later).

At that fair I recall meeting one guy who built a number of homebuilt lasers, as well as another who built a really neat robotics project (it resembled R2D2 of Star Wars fame).To give credit where due, my laser project was an improvement over one my big brother had built years earlier (also for a science fair). In his project (he got the original idea from an Elementary Electronics magazine in 1976) he used an LED (both visible and IR) as a source, and free-space as a medium (no fiber), picking-up the light signals using a parabolic reflector designed as a solar cigarette lighter. With an FPT-100 phototransistor at the focus of the reflector, gathered (modulated) light was collected and the signal amplified.

I present below the abstract for the project scanned from a typewritten (yes, word processors were rare in 1980) page I found in my parent’s attic in 2002.

The First Lasercom System

The first Lasercom system was built for a demonstration in an “open house” night at my school. This is when I decided to use it as my science fair project. First, the laser had to be modulated. The idea for modulation was obtained from an old Popular Science magazine which described a foolproof burglar alarm system. It was hard to foil because it used 60 Hz modulated light source (He/Ne laser) instead of the usual plain red light beam, thus a flashlight cannot be used to “fool” the alarm system.

The article suggested the power line to the laser tube be cut and a small filament transformer be inserted in the circuit. A 60 Hz tone from the power lines is extracted by another transformer and the tone output was fed to the other modulation transformer. It was thought that if a 60 Hz tone can be impressed on the beam then a varying frequency signal could also be used. This method was tested and was found to work quite well.In the first prototype system, the audio signal from a radio was fed to the modulation input on the laser. The beam was split in two parts by a piece of glass. The weaker beam was fed to a silicon phototransistor and to the input of an amplifier. The more powerful beam was reflected off a mirror and then off a second vibrating mirror which was connected to a speaker coil driven by the output of the amplifier. The mirror vibrated in step with the signal, thus the reflected beam also vibrated,making a small laser light show and also demonstrating the principles of light communications.

The diagram to the right shows how the original demonstration system worked.

Once again, two basic ideas came from books. The first was the modulated HeNe laser which I saw in an old Popular Science magazine. That approach, too, was similar to the one used in the Elementary Electronics magazine article in which impressed voltage from a series transformer was used to modulate the bias current (in the magazine article, modulating the LED bias current and in my case, modulating the actual laser tube current). The second was the light show which used a simple mirror bouncing on a membrane stretched across a speaker. Care to guess where that idea came from? Check this out to see the original 70’s psychedelic light show. Most of these units used a projector with colour filters to produce multiple coloured beams. Mine used a HeNe laser to give a sharp ‘dot’ of light. My project was really just putting it all together: The modulated laser to send the audio signal, a photodetector and amplifier (modified cassette recorder) to receive it, and a speaker with a mirror to deflect the beam. There was some decent science in that project and unlike earlier ‘build and show’ projects, I was now putting-together concepts on my own. The modulation of the high-voltage, for example, was the taking of a basic idea and expanding on that idea … the very nature of science itself (i.e. building on known concepts). This was required for any decent project.

By grade ten, I would have loved to have done a laser project but my HeNe laser was dead (it lasted only two years before the soft-sealed tube gassed-out) and besides, I was now fascinated by robotics having seen a neat robot at the CWSF in Waterloo the past year. I decided to use my old (not at the time it wasn’t) Ohio Scientific computer to control a robotic arm (robotic arms were all the rage, after all, Canada just contributed the arm to the space shuttle). I learned all about interfacing (address and data buses, clocks, and all that jazz) and had my computer control a basic arm which was completely homebuilt. The robot is seen here to the far left with the controller (with a panel of LEDs indicating I/O status) towards the bottom of the photo. Another photo of the robot arm shows the arm mounted on a shelf above the controller and computer in the actual project display. The computer, a single-board with integral keyboard, was packaged in a homebuilt plywood case which held the computer, power supply, and the I/O circuitry built on 44-pin cards. The small TV atop the computer served as a monitor (which was large enough, given that the display resolution was only 24-characters by 24-characters.

That engineering project garnered a trip to the International Science and Engineering Fair (ISEF) in Houston, Texas. I did not place at the ISEF but again, the experience was incredible for I was able to see what is required to make an ‘International’ grade project – while it was a good engineering project it demonstrated nothing new or novel. I noted that the projects that _did_ win had certain characteristics and all used references from scientific journals like ‘Applied Physics’. I had to get my hands on those and was told to check the local University library as they often have these collections available to the public. Brock, our local University library, stocks numerous physics journals which served as an invaluable source for ideas. The ISEF just overwhelmed me – the projects were awesome, the venue was huge (the Astrohall in Houston), students from around the world (Japan, China, Sweden, England, etc) were there … it was a great place to exchange ideas. I was also turned-on to science, more-so than engineering at this point in my life.

OK, I was still intrigued by lasers (had been since I saw them in an old 1967 book on lasers) and desperately wanted to construct a working laser ‘from scratch’. My fave? The argon. Having seen these at the Ontario Science Center as well as at a few laser light shows I was in awe at the vibrant green and blue beams. It is still my favourite laser, despite the fact that owning an argon is a bit more art than science. Soooooo …. I set out to build one. Gathering a load of information on the laser I decided a pulsed laser was the only practical way to do it (the gain is high, the average power dissipation is low). I learned basic glassblowing and using soda-lime tubing (which can be worked with a low-temperature propane torch) built a basic laser tube. It took me a week of experimenting with glass to learn _how_ to glassblow well enough to make that tube. The tube used electrodes from a spectrum tube (bought new from a science supply house and cannibalized almost immediately) and the ends of the glass tube were carefully sawed at Brewster’s angle. Quartz pieces (compliments of the glassblower at Brock) were used for tube windows and epoxied on. For a vacuum system all I had available was an old Cenco single stage vacuum pump (compliments of the high school) and I purchased a lecture bottle of high-purity argon (along with the glass tubing, both from Sargent-Welch scientific).

Again, my parents supported my science ‘habit’ and forked-over the $275.69 for parts as seen in this invoice from Sargent-Welch scientific for many of the materials required for the project. Several interesting items to note include (a) the fact that the glass was sold only in large bundles of 5 pounds, (b) the argon gas bottle and valve cost $67.20 in 1982, and (c) I ordered these parts in July for the science fair next March! Indeed, this project (and the ones which followed) involved major investments of time and effort – but I knew that was required for an “International” caliber project. In addition to the items on this invoice, several parts such as high-voltage diodes (Varo VG-20) and capacitors (high-voltage disc type) were ordered from an electronics component supplier adding to the cost of the project (which was probably $500). Of course there was also an order to Edmund Scientific for the aluminized mirrors.

Finally, the last item on this invoice “belt” was for a VanDerGraff generator I built for a friend which used a teletype motor to drive a belt within a piece of black ABS plumbing. Two stainless-steel salad bowls served as the top high-voltage terminal.

Well, constructing a gas laser, especially a low-gain one like an argon, on a piece of 2-by-4 lumber is begging for disaster and the laser never really ran as a laser. I could not afford proper (i.e. concave with a dielectric coating) mirrors and so a first-surface enhanced-aluminum telescope mirror was used with the hopes that the pulsed gain of the blue argon line would overcome losses in the laser. This was probably the biggest problem with the design: had I thought harder (and done some calculations using the gain threshold formula), I’d have made the laser 2m long since a 2m long pulsed argon would likely have exhibited over 30% gain and the bugger might have worked. Mind you, this was by no means a loss as I learned an ENORMOUS amount about vacuum systems, high voltage work, and other techniques I’d need now and in the future (even now, my early experiences with high vacuum are invaluable). Still, what to do with the argon in which I’d now invested precious time (started in July, completed by December) and (my parents’) money? The answer was in an journal article (in the Journal of Applied Physics, Vol 48, No 3, pp. 1385) concerning the ‘plasma pinch’ effect in which a high current through a gas plasma generates a magnetic field which ‘pinches’ the plasma causing current to be reduced after which the plasma expands and current increases: the plasma current hence oscillates. By this time I was begging Mom to drive me to the local University library and leave me there for the afternoon. I spent hours in that place, bringing along with pockets of change for the copier.

I needed a decent oscilloscope (which I borrowed from Mr. Zavitz who serviced electronics and was also an Ohio Scientific computer enthusiast, hence how I met him) and an open-shutter 35mm camera to record the oscillations occurring in the discharge {This all seems so primitive today – now I simply plug a USB key directly into my scope and capture it}. Current was monitored with a Rogowski coil (a small transformer) in series with the discharge (small enough that its inductance did not affect the discharge much). A typical oscillograph is shown to the left. Because the photos were quite dim (the camera captured only a single trace of the scope beam) the output was traced onto a piece of translucent drafting film and placed on to of the original photo. The observed trace shown here was from the upper-edge of a low-pressure discharge of 88.2A. An 8.25MHz oscillation was observed.

Aside from the primitive vacuum system, the power supply consisted of a small neon sign transformer (obtained from a surplus store) with variac to control power, a few HV diodes ordered from an electronics supply house, and the handmade laser tube.

The above photos show the power supply (with a small neon sign transformer), capacitors used in the project, and the laser tube, glowing, with an argon discharge. Click here to see a detailed view of the laser – all the gory details including copious quantities of vacuum wax used to seal the tube.

In grade 11 I entered that project, which also featured a presentation board of ‘International’ caliber (it was freestanding and about eight feet tall), and did extremely well at the local fair winning a trip to the International Science and Engineering Fair (ISEF) in Albuquerque, NM that year.

 

I present the abstract for that project below:

CURRENT MODULATION IN THE PULSED ARGON-ION LASER DISCHARGE

This is an investigation of the phemonemon, factors affecting, and the causes of current modulation in the pulsed argon-ion laser discharge. If the amplitude of the modulation varies inversely as tube pressure and occurs only at high discharge currents, it may prove that the modulation is caused by the plasma pinch effect. The pinch effect, which may be responsible for the modulation during the main part of the current pulse, is calculated to occur at discharge currents of 30A or greater. The modulation occurred only when employing the 1 uF discharge capacitor and only at the upper and mid-trailing edges of the current pulse. The amplitude of the modulation was varied to a greater degree at the lower-trailing edge than at the upper-trailing edge. In addition, modulation frequency increased at the lower-trailing edge of the current pulse. The data suggests that the modulation does occur in the laser discharge, varies inversely as tube pressure and occurs only at high discharge currents. As large currents are needed to cause the modulation, these findings seem to indicate that a cycle of plasma pinch and destruction of the pinch is responsible for the modulation. Since the frequency of the modulation is lower at the upper-trailing edge of the current pulse, it seems that ion-acoustic waves are present as a cause of the modulation during the early part of the pulse.

  • First Award – Optical Society of America
  • Third Award – General Motors ISEF

It placed third overall in the ISEF (quite respectable) in the physics category. Aside from placing, the trip itself was just spectacular! I have fond memories of that trip – it was my favourite science fair trip of all time – and here are a few highlights …

Sandia Peak
Santa Fe
Geek Haven
Laserium laser light show
Hot air balloon festival

At the fair in NM, I met James G. Small from MIT. At the time I recall saying something dumb like ‘you wrote the article in the Amateur Scientist on the dye laser’? Close … he wrote the article on the nitrogen laser, now famous with almost all laser enthusiasts! We talked for over an hour and essentially designed my _next_ year’s project. I’d tried to build a nitrogen before, but did it all wrong using thick copper plates. He put me on the right path and for that I was grateful! In the bowels of Active Surplus in Toronto I found the required thin PC board (0.015″ thick) from which the laser was built. I used that single-stage vacuum pump to evacuate the tube and rented a Q tank of nitrogen on my brother’s account at the local welding gas supplier (he had an oxy-acetylene welder and so had an account with them for tanks). I borrowed his oxygen regulator which, with an adapter, regulated the flow of nitrogen into the laser. After a few blown PC boards, the laser was at last a success, and I was on my way to building a dye laser for experiments.

The Scientific American Amateur Scientist article written by Small in the 1970’s describing the construction of a simple nitrogen gas laser which outputs in the ultraviolet was, of course, the inspiration for the construction of my nitrogen pump laser.

This is a scan of the only remaining photo of my first working dye laser prototype (an old instant Polaroid photo). UV radiation from the nitrogen pump laser enters from the upper-right passing through the cylindrical lens (mounted on a focussing tube from an old microscope) and onto a cell containing Rhodamine-6G dye solution. The flat HR and OC are in the triangular mounts on either side of the cell. The entire laser was built on a piece of 1-by-6 wood. It was built simply to prove that it could indeed be done and despite the simple construction, worked extremely well producing a bright yellow beam.

The actual laser used in the experiment (outlined in a photo below) was much more stable: it was built on a 3/4″ thick piece of aluminum with aluminum mounts for all optics, a precision rotating stage using multiple bearings for a diffraction grating used to select the output wavelength, and space was provided between the dye cell and the grating for additional collimating and wavelength-selecting optics. The main point of the experiment was to use an inexpensive dielectric filter as an intra-cavity etalon to reduce the linewidth of the laser output drastically.

Dye Cell lasing
The Laser and Controller

The apex of my science fair project experience is seen in this photo. My 1984 science fair project placed first prize in the 35th International Science and Engineering Fair (ISEF) held in Columbus, Ohio that year. As well, I had won a trip from the US Air Force to visit several R&D facilities in Maryland, Ohio, Tennessee, Texas, and Florida – I was the only non-US citizen to have won such an award.

The ISEF is the Olympics of science fairs and is the only international science competition for students in grades 9 through 12. In the 80’s, the major corporate sponsor for the ISEF was General Motors. Nowadays it’s Intel for the IISEF

I left the project display board at the fair since it was a considerable expense to ship it back however I did remove the photos (and whatever else could be ripped from the board) and recently, a remaining piece of the project was located in my parents’ attic as seen in these photos:

Observations
Apparatus
Typical spectrographs
Spectral Width

This project examined novel tuning mechanisms for a dye laser. A crude (but high powered) nitrogen laser was used to pump a tunable dye laser. The project took a full year to construct. The abstract describing that project from the 35th ISEF:

WAVELENGTH SELECTION IN THE TUNABLE DYE LASER

The experiment presented will investigate the factors affecting the spectral characteristics of a nitrogen laser pumped tunable dye laser. The wavelength selection system is unique as it uses a medium resolution diffraction grating instead of a high dispersion type usually found in this type of laser, thus a grating used alone as a wavelength selector should yield high spectral widths of the laser output. The use of intra-cavity wavelength limiters -an optical slit or filter- should reduce the spectral width to approx. one nanometer. Rhodamine 6G; 7 diethyl amino, 4 methyl coumarin; sodium fluorescein; a mixture of the two preceeding dyes; and 4 methyl umbelliferone were employed as the organic lasing dyes. Ethanol was found to produce the strongest and most stable lases. Tested concentrations varied between 5 x 10-5 m/l and 1 x 10-2 m/l. Using a 600 line/mm diffraction grating alone, spectral widths of approx. 6 nm were produced. The use of an intra-cavity optical slit between the dye cell and grating reduced the spectral width by one-half, while the use of a dielectric filter (As a Fabry-Perot interferometer) reduced the spectral width to 1.2 nm. Using five dye solutions, a continuous wavelength range from 602 nm to 392 nm can be covered. Since the wavelength range is so broad, the laser may be useful as a spectrographic emission source; however, a high dispersion grating must be used to obtain low spectral widths. Data obtained on the use of a slit or filter can be applied to a laser employing such a grating. 

  • First Award – American Association of Physics Teachers
  • First Award – General Motors ISEF
  • First Award – United States Air Force
  • Honorable Mention – Optical Society of America

There was real science in there: like my grade 9 project I took a common element (dielectric filters) and applied it in a novel manner. Where many lasers used an expensive etalon to reduce spectral width, this one used an inexpensive dielectric filter. And unlike my previous project where I lacked the mathematical knowledge to fully describe and predict the effect I was seeing, I researched this one thoroughly and understood the ins and outs of dielectric filters and gratings!

Here’s a few shots from that fair:

My project
Where's My Project??
Proud as a peacock
Columbus zoo
Gary Hart

Winning first award was a huge honour, but perhaps the best prize of all was the USAF award which included a week-long trip to air force R&D bases around the US (it was one of the most highly prized awards at the ISEF at the time and apparently, I was the first non-US citizen to ever win this award).

It was a truly once-in-a-lifetime experience …

Andrews AFB
Secretary of the Air Force
C-130 transport
Arnold AFB
USAF photo

To find out more about the laser I used in that project check out the Dye Lasers Page on the as the Homebuilt Lasers Site which also details the design of these lasers.

In the course of researching this project I had photocopied almost every laser article in the Amateur Scientist columns. As well, I used a good number of scientific journals for information: Applied Physics, Applied Physics Letters, and the like. I spent a good deal of time in the library at Brock University researching (this was, of course, long before the web and so information on amateur laser construction was much more difficult to come-by.

Finally, in grade 13 (in Ontario, at the time, high school was five years), I entered a two-year project entitled “Wavelength Selection in Tunable Dye Lasers”.

The project was essentially a comparison of the spectral characteristics of the nitrogen-laser pumped dye laser (1984’s project) to that of a new flashlamp-pumped laser.

This laser was built around a capacitor obtained from a surplus defibrillator purchased from a surplus store in Buffalo, NY.

A close-up of the project itself shows the flashlamp-pumped laser on top and the computer-control underneath. The computer, an Ohio Scientific 6502-based system, was built into a PDP-8/A case as seen here. The laser was configured as a spectroscopic light source – the computer controlled a step-motor which tuned the laser through the entire range. The laser was fired at intervals, and the transmission through the sample recorded. Beside the monitor and the keyboard are the controllers: the top panel controls the laser itself (charging of the capacitor and firing the flashlamp) and the lower panel the interface between the computer and grating drive.

The project was more engineering than science and the flashlamp-pumped laser lacked a totally unique element (unlike the nitrogen-laser pumped dye laser) – frankly, it was a matter of biting off too much. I should probably have concentrated on the optical elements of the laser instead of the computer-control system as I did. Regardless, I won the local fair and it was suggested that I go to the CWSF (in Cornwall that year) rather than the ISEF since the project was very similar to the previous year’s entry. I placed second at the CWSF that year.