Laser

Laser audio micro-course (transcript)

Three short podcasts about “Laser”. Listen with the interactive player.

Podcast 1 — Introduction & meaning

Narrator: Laser. A noun and verb. Pronounced /ˈleɪ.zər/.

Narrator: Laser is an acronym: Light Amplification by Stimulated Emission of Radiation. The term was coined in 1959 by the physicist Gordon Gould, who had earlier coined the related term maser — Microwave Amplification by Stimulated Emission of Radiation. The first working laser was constructed by Theodore Maiman on the sixteenth of May 1960, using a synthetic ruby crystal as the active medium. The foundational physics — the stimulated emission mechanism — had been described by Albert Einstein in 1917, forty-three years before the first laser was built.

Narrator: What distinguishes laser light from ordinary light is coherence. Ordinary light is incoherent — its waves have random phases and mixed wavelengths. Laser light is coherent — all its photons are in phase, travelling in the same direction, with the same wavelength. This coherence allows laser light to be focused to an extremely small spot, to travel long distances without spreading, and to carry immense intensity in a narrow beam.

Narrator: The laser's applications span an enormous range. In medicine: laser surgery for eye correction, cancer ablation, dermatology, and dental procedures. In industry: laser cutting and welding of metals, precision machining, 3D printing. In communications: fibre optic networks transmit data as pulses of laser light. In measurement: laser rangefinders and geodetic measurements. In consumer electronics: optical disc players, barcode scanners, laser printers. In science: spectroscopy, atom trapping, gravitational wave detection.

Narrator: Laser is one of the most successful acronyms in the English language — so thoroughly adopted as an ordinary word that most people who use it daily are unaware that it was ever an acronym at all.

Narrator: Laser. The acronym that became a word — describing the most versatile beam of light in the history of technology.

Speaker A: The laser being one of those technologies where the initial inventors had almost no idea of the eventual applications — Maiman being asked what it was for and not having a clear answer.

Speaker B: The solution looking for a problem being one of the more accurate descriptions. The laser as a fundamental physical tool whose applications proliferated as people found ways to exploit its properties.

Speaker A: Laser eye surgery being one of those technologies that seemed extraordinary when it first appeared and now feels almost routine.

Speaker B: The normalization of precision laser ablation of living tissue happening remarkably quickly. A technology that removes millimetres of cornea with a laser becoming a lunchtime procedure.

Speaker A: The coherence being the key property — ordinary light spreads, laser light maintains its intensity over distance.

Speaker B: Which is why laser pointers reach a wall as a dot and a torch illuminates everything nearby. The directionality coming from the coherence. The lack of divergence making the laser useful where ordinary light fails.

Speaker A: LIDAR in autonomous vehicles being a laser application that has become suddenly significant — using laser pulses to map the environment at speed.

Speaker B: The same principle as radar but at optical wavelengths. Much higher resolution mapping because the shorter wavelength gives finer detail. The sensor technology from astronomy and geodesy being applied to navigation.

Speaker A: The laser-pointer cat toy being perhaps the most everyday domestic application of Einstein's 1917 physics.

Speaker B: A theorem about photon emission from 1917 being the foundation for an inexpensive red dot that cats chase. The distance between the fundamental physics and the consumer product is always amusing.

Speaker B: Build a Next.js the physics of laser light and stimulated emission for a physics teacher — documenting how lasers work at the level of quantum mechanics and stimulated emission, reviewing Einstein's B coefficient, population inversion, and laser physics, generating a laser physics framework, and producing a laser quantum physics guide.

Speaker A: Laser physics documented with quantum mechanics analysis so teachers explain both the stimulated emission mechanism — how a photon encountering an excited atom stimulates the emission of a second photon with identical wavelength, phase, and direction — and the population inversion: how lasers achieve more atoms in excited states than ground states to achieve net amplification.

Speaker B: Design a Django medical lasers and their applications in surgery and treatment for a medical specialist — documenting the medical applications of laser technology across specialties, reviewing laser surgery, LASIK, and photodynamic therapy, generating a laser medical applications framework, and producing a laser medical technology guide.

Speaker A: Medical lasers documented with clinical analysis so practitioners explain both the wavelength selectivity — how different laser wavelengths are absorbed selectively by different tissues enabling precise targeting — and the major applications: how LASIK uses excimer laser ablation of corneal tissue, how Nd:YAG lasers treat posterior capsule opacification.

Speaker B: Create a Svelte LIDAR and laser applications in autonomous vehicles for an automotive engineer — documenting how LIDAR uses laser technology for autonomous vehicle sensing, reviewing LIDAR, point cloud, and autonomous driving sensors, generating a laser LIDAR automotive framework, and producing a laser LIDAR autonomous vehicle guide.

Speaker A: LIDAR in autonomous vehicles documented with automotive engineering analysis so practitioners explain both the operating principle — how LIDAR emits laser pulses and measures return time to generate three-dimensional point clouds of the surrounding environment — and the comparison: how LIDAR's high angular resolution and range accuracy compare to radar and camera in autonomous driving sensor fusion.

Speaker B: Build a Vue the history of laser development and Gordon Gould's patent dispute for a science historian — documenting the history of laser invention and Gordon Gould's contribution, reviewing Maiman, Gould, and laser patent history, generating a laser invention history framework, and producing a laser development science history guide.

Speaker A: Laser invention history documented with science history analysis so researchers explain both the Maiman achievement — how Theodore Maiman's ruby laser of May 1960 demonstrated the first working laser — and the Gould patent dispute: how Gordon Gould spent decades pursuing patent rights to the laser acronym and key laser applications.

Speaker B: Develop a React Native fibre optic communications and laser light transmission for a telecommunications engineer — documenting how lasers enable modern fibre optic communications, reviewing optical fibre, wavelength division multiplexing, and data transmission, generating a laser fibre optic telecommunications framework, and producing a laser telecommunications guide.

Speaker A: Fibre optic laser communications documented with telecommunications analysis so practitioners explain both the transmission mechanism — how modulated laser light pulses encode digital data and travel along optical fibre — and the wavelength division multiplexing: how multiple wavelengths transmitted simultaneously multiply the capacity of a single fibre.