Lasers from theory to tool: how a laboratory curiosity became indispensable to industry

Walk through a modern fabrication shop and lasers are everywhere: cutting steel sheet into precise profiles, welding thin assemblies, marking part numbers, aligning machines and measuring large structures. Beyond the workshop, lasers carry most of the world’s internet traffic through optical fibres, read barcodes at supermarket checkouts, correct eyesight, scan the surroundings of vehicles and measure distances to satellites. It is hard to think of an industry untouched by them.

Yet when the first working laser was demonstrated in 1960, nobody knew quite what it was for. It was widely described as a solution looking for a problem. It took decades, and many separate developments in materials, power, reliability and cost, before lasers became everyday tools. Their history is one of the clearest examples of how an enabling technology develops: from scientific insight to laboratory demonstration, to specialist uses, to steady improvement, to applications that the original inventors could not have imagined.

This article traces, in general terms, how the laser developed, how the main types of industrial lasers emerged, how lasers found their way into manufacturing, measurement, communication and medicine, and what their history teaches engineers and businesses about developing and adopting new technologies. It is a general historical overview.

The physics behind the beam

The word laser is an acronym for light amplification by stimulated emission of radiation. Its foundation lies in a theoretical insight published by Albert Einstein in 1917: in addition to absorbing and spontaneously emitting light, atoms in an excited state can be stimulated by an incoming photon to emit a second photon identical to the first, with the same wavelength, direction and phase.

If a material can be arranged so that more of its atoms are in an excited state than in the lower state, a condition called population inversion, then light passing through it can be amplified. Place that material between mirrors, so light passes back and forth many times, and the amplification can build into an intense, highly directional, single-wavelength beam.

For decades, this remained a theoretical possibility. Achieving population inversion and building suitable optical cavities required advances in physics and engineering that came only after the Second World War.

From maser to laser

The first practical device based on stimulated emission worked with microwaves rather than light. In the early 1950s, researchers in the United States and the Soviet Union developed the maser, microwave amplification by stimulated emission of radiation, which found uses in sensitive amplifiers and atomic clocks.

Extending the idea to visible light posed new challenges: suitable materials, ways to pump energy into them and optical resonators that could sustain the beam. Several research groups pursued the problem in the late 1950s, and in 1960 Theodore Maiman demonstrated the first working laser, using a synthetic ruby crystal pumped by a flash lamp. Within a few years, many other types followed.

The main laser types

Different ways of creating the lasing medium produced lasers with different wavelengths, powers and characteristics:

Each type opened particular applications. The history of industrial lasers is less about one invention than about a succession of laser types, each better suited to certain jobs, and about the gradual improvement of power, efficiency, reliability and cost.

Lasers in manufacturing

Cutting

Laser cutting focuses a high-power beam to a small spot, melting or vaporising material, while an assist gas blows the molten material out of the cut. Carbon dioxide lasers made laser cutting of sheet metal and non-metals commercially practical. Fibre lasers later transformed sheet metal cutting, especially of thinner sheet, through high efficiency, beam quality suited to metals and lower maintenance. Laser cutting replaced much punching and blanking for low and medium volumes, because it requires no hard tooling and can switch between part designs instantly. The choosing a cutting process for plate and sheet article compares laser cutting with plasma, waterjet and other methods.

Welding

Laser welding concentrates heat in a small area, producing narrow welds with limited distortion at high speed. It is used widely in automotive bodies, battery manufacturing, medical devices, electronics and precision assemblies. Its precision demands good joint fit-up and control.

Marking, drilling and surface treatment

Lasers mark part numbers, barcodes and logos permanently without contact, drill small holes in hard materials, harden surfaces locally, clean surfaces and texture them. Ultrafast lasers machine fine features with minimal heat damage, enabling micromachining of medical devices and electronics.

Additive manufacturing

Lasers are the heat source for many additive processes, including laser powder bed fusion of metals and laser sintering of polymers, and for directed energy deposition used to build up and repair parts.

Lasers in measurement

The laser’s highly coherent, single-wavelength light made new levels of measurement possible:

• Interferometry uses the wavelength of light as a ruler, allowing extremely precise measurement of distance and position, used to calibrate machine tools and measuring machines.
• Laser trackers measure large structures and assemblies accurately in three dimensions, in aerospace, shipbuilding and heavy engineering.
• Laser scanners capture the shape of objects and buildings as point clouds, used in reverse engineering, inspection and building information modelling.
• Alignment lasers align shafts, rails and machinery.
• Laser rangefinders and LiDAR measure distance by timing reflected pulses, used in surveying, mapping and vehicle sensing.

Lasers in communication and information

Semiconductor lasers combined with low-loss optical fibre transformed communications. From the 1970s and 1980s onwards, optical fibre links carried increasing amounts of telephone and data traffic, and today fibre networks form the backbone of the internet, including undersea cables connecting continents. Lasers also made optical data storage, such as compact discs and their successors, and laser printers possible, bringing laser technology into everyday homes and offices.

Lasers in medicine

Lasers are used to reshape the cornea in vision correction, treat eye conditions, perform precise surgery, treat skin conditions and support diagnostic imaging. Medical lasers illustrate the importance of matching wavelength and pulse characteristics to the way tissue absorbs light.

Why adoption took decades

The gap between the first laser in 1960 and the widespread industrial use of lasers decades later was filled by many incremental advances:

• Power: early lasers were too weak for most industrial work.
• Reliability: laboratory devices needed constant attention; production tools must run for thousands of hours.
• Efficiency and running cost: early lasers converted only a small fraction of input power into light.
• Beam delivery: mirrors, fibres and focusing optics had to deliver the beam where needed.
• Control systems: CNC motion systems, sensors and software made lasers usable on production lines.
• Cost: prices fell as volumes rose, particularly for semiconductor and fibre lasers.
• Knowledge: users had to learn process parameters, joint design and safe operation.

This pattern, an initial breakthrough followed by long, cumulative improvement in surrounding technologies, is typical of enabling technologies. The learning curves and zero fuel cost article shows a similar pattern in solar panels and batteries.

Safety

Lasers can cause eye injuries, burns and fires, and industrial laser processes can produce hazardous fumes. Lasers are classified according to their hazard, and higher-class industrial lasers require enclosures, interlocks, controlled areas, training and appropriate eye protection. Fume extraction is essential for cutting, welding and marking, especially of coated materials and plastics. These controls sit within employers’ work health and safety duties, and Australian standards for laser safety provide guidance.

Qualifying laser processes in production

Bringing a laser process into production involves more than buying the machine. Laser cutting and welding results depend on many parameters: power, speed, focus position, spot size, assist or shielding gas type and pressure, nozzle condition, material grade, thickness and surface condition. Small changes, such as a different coating on the sheet or a worn nozzle, can change edge quality or weld penetration.

Successful users treat laser processes as controlled processes. They develop and record parameter sets for each material and thickness, verify them with test cuts or welds, inspect samples, for example by sectioning welds to check penetration, and control changes. Preventive maintenance of optics, nozzles and beam delivery protects consistency. Where welds are structurally important, procedures and qualification requirements similar to those for other welding processes apply.

When lasers are not the answer

Lasers are versatile, but other processes sometimes do the job better. Very thick plate may be cut more economically by plasma or oxy-fuel. Heat-sensitive materials or composites may be better cut by waterjet. High-volume simple shapes may be cheaper to punch or stamp once tooling exists. Joints with poor fit-up may suit arc welding better than laser welding. The best decisions compare processes on cost, quality, speed and flexibility for the actual parts and volumes involved.

Lessons for engineers and businesses

Enabling technologies find their uses over time

The laser’s inventors could not foresee fibre optics, barcode scanners or laser cutting of sheet metal. Many of the most important applications emerged from people who understood a specific problem and saw how the laser could solve it. Businesses evaluating new technologies should look for the problems in their own operations that a technology could address, rather than waiting for someone else to package the solution.

The supporting system matters as much as the core invention

A laser alone cuts nothing. It needs beam delivery, motion control, assist gases, software, process knowledge and safety systems. When adopting any technology, assess the whole system required to make it productive.

Each variant serves different jobs

There is no single best laser. Carbon dioxide, fibre, diode and ultrafast lasers each suit different materials and tasks. Similarly, technology choices in any business should match the specific job, not general reputation.

Cost curves change the decision

Technologies that are uneconomic at first can become compelling as costs fall. Revisiting earlier decisions periodically, as prices and capabilities change, can reveal new opportunities that were not available when the original choice was made.

A worked example

This is an illustrative example. The business and figures are hypothetical.

A small sheet metal fabricator has used a turret punch for many years. Its work has shifted towards smaller batches of more varied parts, and it spends increasing time making and changing punch tooling for special shapes. It considered a laser cutter ten years ago but found it too expensive for its volumes.

Revisiting the decision, the owner finds that fibre laser cutters have become more affordable, more efficient to run and easier to maintain. A study of the previous year’s work shows that about 60% of parts would be faster to produce by laser, with no tooling, and that special tooling purchases would largely disappear. The business buys a fibre laser, retains the turret punch for formed features and high-volume punched parts, and invests in operator training, fume extraction and laser safety controls. Lead times for new parts fall from about two weeks to a few days, because there is no tooling to make. The business records cutting parameters for each material and thickness it uses and checks edge quality on the first part of every job, so that results stay consistent as operators and materials change.

How this applies to a small Australian business

• Revisit technology decisions as costs and capabilities change.
• Start from your problems, then look for technologies that address them.
• Assess the whole system: equipment, software, skills, maintenance and safety.
• Match the technology variant to the job.
• Use lasers for measurement as well as making, such as alignment and scanning.
• Treat laser safety seriously, including enclosures, interlocks, eye protection and fume extraction.
• Control laser processes with recorded parameters, first-part checks and maintenance of optics and nozzles.

Questions worth considering

• Which of our processes could be faster, more flexible or more precise with a technology we dismissed in the past?
• What supporting capabilities would a new technology require from us?
• Are we matching technology choices to specific jobs, or to general reputation?
• When did we last revisit a major technology decision?
• How do we evaluate the safety implications of new equipment?
• Do we treat new processes as controlled processes, with recorded parameters, verification and change control?

Bringing it together

The laser grew from a theoretical prediction in 1917 to a laboratory demonstration in 1960 and then, through decades of cumulative improvement, into an indispensable industrial, scientific, communications and medical tool. Different laser types suited different tasks, and adoption depended as much on power, reliability, efficiency, beam delivery, controls, cost and process knowledge as on the original invention. The laser’s history shows how enabling technologies find their uses, why whole systems matter and why decisions about technology should be revisited as costs and capabilities change.

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Source: KEVOS editorial notes. This article is a general historical overview.