雅思阅读 198: The Light They Could Not Reject — How the Laser Finally Came（无法拒绝的光：激光的诞生）

改编自 Physics in Perspective / 中国激光杂志社（2011-2025年）。雅思阅读 Section 3 难度，约 1050 词。 素材来源：https://clp.ac.cn/News/Details?id=PT251231000200V2Y5b&type=latest

Reading Passage

A. Strange as it sounds, the idea behind the laser predated the first working device by more than four decades. In 1917 Albert Einstein pointed out that an excited atom could be prodded into emitting light by a passing photon of the right colour — a process he called "stimulated emission". Ordinarily an excited atom spits out light when it feels like it, in a random direction; Einstein's addition was that a matching photon could trigger the release of an identical copy. The insight was purely theoretical: Einstein did not build anything, and for nearly forty years the phenomenon remained a curiosity of textbooks with no known use. When engineers finally learned to exploit it, they first did so not with light but with microwaves. The device that preceded the laser was the maser, demonstrated in 1954, which amplified microwaves in much the way Einstein had imagined. It worked well enough to anchor early atomic clocks and radio telescopes, but it operated at the low-frequency end of the electromagnetic spectrum, where wavelengths are long and information capacity is limited. The prize — amplifying ordinary visible light — still lay waiting, and everyone suspected it would be harder: shorter wavelengths demanded materials and mirrors no one had yet mastered.

B. The first person to win that prize was Theodore Maiman, a physicist at Hughes Research Laboratories in California. On 16 May 1960, his device produced a narrow beam of deep-red light from a rod of pink ruby roughly a centimetre long. He coated the ends of the ruby with silver to act as mirrors and surrounded it with a flashlamp, whose brief blast pumped the atoms into their excited state; when they relaxed, they emitted the characteristic wavelength of 694.3 nanometres. The mirrors fed the light back and forth through the ruby, letting it amplify into a beam that emerged from one partially silvered end. The name itself — an acronym for Light Amplification by Stimulated Emission of Radiation — was coined later. The story's most telling detail is how the discovery was received: Maiman's manuscript was turned away by a leading journal, whose editors assumed it was merely a variation on the already familiar maser. Announced instead through a newspaper and eventually published in a British journal, the invention nonetheless spread with remarkable speed. Within a few years, laboratories around the world had built their own versions from other materials, tuned to other colours.

C. What set this light apart from a candle or an electric bulb was not its brightness but its order. An ordinary source emits photons in all directions, at many wavelengths and with no shared rhythm — a jumble that disperses and dims within metres. Stimulated emission, by contrast, clones each photon that passes through: the new photon travels in the same direction, at the same wavelength and in step with the original. The mirrors at the ends of the crystal force the light to bounce again and again, so that a tiny input of light is amplified into a bright beam in a matter of nanoseconds. The result is a beam that stays narrow over vast distances, pure in colour, and coherent as a marching column. It can be focused to a spot smaller than a pinhead or fired at a mirror left on the Moon in 1969, and still return a faint echo. This is why the same device could be made to cut metal, read a disc or measure distance to within centimetres. The trick was not to make brighter light but to make light that behaved. That single property explains why the laser escaped the laboratory so quickly.

D. Almost at once, people began to imagine the laser as a carrier of communication. Ordinary radio and television already used electromagnetic waves to carry speech and pictures, and the higher frequency of light promised to pack vastly more information into the beam — thousands of conversations in the space that radio waves spent on a handful. Within months of Maiman's demonstration, researchers at Bell Labs had carried a laser signal over forty kilometres, and by 1961 the physicist Charles Townes was writing seriously about optical communication across interplanetary space. The obstacle proved not the beam itself but how to guide it; sending light through open air was unreliable in rain and fog, and it took the invention of transparent glass fibre — thin strands that trap light by repeated internal reflection — to turn the dream into the internet's backbone. The laser, in the end, became less a weapon than a voice, whispering pulses of light through glass laid under the world's oceans. A single thin fibre can now carry more telephone calls than all the copper cables of a generation ago combined.

E. The history carries a quiet irony. The Nobel Prize that recognised the field went in 1964 to Townes and to two Soviet physicists, for the theory behind stimulated emission; Maiman, who actually built the first device, was never similarly honoured, and his achievement was recognised chiefly through prizes from professional societies rather than the highest one. Such quibbles aside, the invention touched nearly every corner of modern life — surgery, printing, measurement, barcode scanning and data transmission among them. In medicine, a focused laser can cut tissue with less bleeding than a knife; in manufacturing, it welds and drills with a precision no blade can match. What began as a theoretical footnote in Einstein's papers ended as a technology that organises the flow of information across the planet. It remains a useful reminder that the most consequential inventions often arrive quietly, are doubted by their own journals, and only later reveal how thoroughly the world was waiting for them.

Questions 1-4

Choose the correct heading for paragraphs B, C, D and E from the list of headings below.

List of Headings i. The first ruby beam — and the journal that doubted it ii. Einstein's theoretical prediction and the maser iii. What makes laser light different iv. The dream of light as a communication carrier v. Why glass fibre was invented vi. The Nobel Prize and the invention's legacy vii. How to build a maser

1. Paragraph B: ____
2. Paragraph C: ____
3. Paragraph D: ____
4. Paragraph E: ____

Questions 5-8

Choose the correct letter, A, B, C or D.

5. What did Einstein contribute in 1917? A. He built the first working laser. B. He described stimulated emission as a theoretical possibility. C. He invented the maser. D. He discovered ruby.

6. What was unusual about Maiman's first laser? A. It emitted microwaves rather than light. B. It used a ruby rod excited by a flashlamp to produce red light. C. It was never accepted by any journal. D. It required a glass fibre to work.

7. Why is laser light described as "orderly" compared with ordinary light? A. It is always brighter than sunlight. B. Photons travel in step, in one direction, at one wavelength. C. It can only be produced at night. D. It contains many mixed colours.

8. What eventually made optical communication practical? A. Sending signals through open air. B. The invention of transparent glass fibre to guide the light. C. Abandoning the laser for radio waves. D. Using silver mirrors outdoors.

Questions 9-13

Do the following statements agree with the claims of the writer?

Write:

• TRUE if the statement agrees with the information
• FALSE if the statement contradicts the information
• NOT GIVEN if there is no information on this

9. The maser, built in 1954, amplified microwaves.
10. Maiman's first laser produced blue light at 694.3 nanometres.
11. Bell Labs carried a laser signal over forty kilometres within months of Maiman's demonstration.
12. Maiman received the Nobel Prize in 1964.
13. Maiman's father worked as a professional photographer.

Questions 14-15

Complete the summary below using NO MORE THAN TWO WORDS from the passage.

Maiman coated the ends of his ruby rod with silver to act as (14) __________, and the acronym LASER stands for Light Amplification by Stimulated Emission of (15) __________.

答案与解析

← 上一篇 | 返回雅思焦点 | 下一篇 →