Last time, I showed you how you could construct a photon, a light particle, in a configuration of mirrors called a ring cavity. This time I’ll show you that sometimes, you can’t make just one particle—they only come in pairs. And sometimes, the notion of a particle doesn’t make any sense at all. (This post relies heavily on last week’s post, so if you haven’t read that, I recommend you do so.) Disclaimer: What I’m about to describe is only the simplest case, and I make simplifications for the sake of exposition. It is possible to capture and manipulate
optics
Physics / Quantum Mechanics / Science And Math
What’s in a Particle?
If you’ve read or heard anything about quantum mechanics, you’ve heard the phrase “particle-wave duality.” The common wisdom is that this means that particles sometimes behave like waves and sometimes behave like particles. And although this is right, it’s a bit misleading. The truth is: Everything is always a wave. It’s just that waves can be made to behave like particles. To see what I mean, let’s actually show how one can make a set of waves behave like a particle. Specifically, let’s show how a set of light waves can be made to behave like a photon, a light particle.
Condensed Matter / optics / Physics / etc.
Graphene and Me: My Brush with the Wonder Material
Graphene, a two-dimensional honeycomb lattice of carbon atoms, has made waves in science and technology circles. Last week, I gave a brief overview of the history of the stuff and why it’s special. This week, I’d like to continue the story by talking about applications. Unfortunately for us—and fortunately for society as a whole—graphene has spawned so many new technologies that it’s impossible for me to discuss them all. So instead, I thought I’d talk a single application that has personal value to me. As an undergraduate student, I spent two years in a laser lab studying graphene’s applications
Condensed Matter / optics / Physics / etc.
Graphene: The Story of the Wonder Material
I call our world Flatland, not because we call it so, but to make its nature clearer to you, my happy readers, who are privileged to live in Space. ~A. Square In the past few years, you’ve probably heard something about graphene—whether as a replacement for silicon, as the next generation of organic solar cell, as the material in fast-charging batteries, or as one of the strongest materials ever discovered. There’s been so much hype that people have begun calling the flood of research and investment the graphene gold rush. In this post, I’ll give you a brief primer
optics / Physics / Quantum Mechanics / etc.
Mode-Locked Lasers: The Beating Pulse of Metrology
Your hand opens and closes, opens and closes. If it were always a fist or always stretched open, you would be paralysed. Your deepest presence is in every small contracting and expanding, the two as beautifully balanced and coordinated as birds’ wings. ~Rumi Although we don’t usually notice them, ultrafast pulsed lasers are all around us. They are keep time in the atomic clocks on GPS satellites. Metrologists and chemists use them to measure the properties of atoms and molecules. Astronomers use them to measure the color of light from distant stars. Particle physicists use them in supercollidors. Materials
optics / Physics / Quantum Mechanics / etc.
Scattering Part Two: A Quantum of Scattering
We come spinning out of nothing, scattering stars like dust! ~Jalāl ad-Dīn Muhammad Rūmī Last week, I explained Rayleigh and Raman scattering from a classical point of view. In the process, I explained why the sky is blue and introduced Raman spectroscopy, a powerful tool for studying the structure of molecules. This week, I fill in the gaps and explain scattering from a quantum-mechanical point of view. Before we can talk about scattering, though, we need to review some important ideas from quantum mechanics: energy levels and the Heisenberg uncertainty principle. Energy Levels The story of energy levels starts
optics / Physics / Quantum Mechanics / etc.
Why The Sky is Blue: Lord Rayleigh, Sir Raman, and Scattering
The Sky is the Daily Bread of the Eyes ~Ralph Waldo Emerson At some point in his or her life, almost every child on Earth asks, “Why is the sky blue?” The question is so prevalent that, to me, it has come to represent the wonder that the world holds for a a child. Adults don’t ask such questions… at least, not unless they’re scientists. Part 1: John Tyndall In 1859, physicist John Tyndall thought he’d found the answer to the sky’s color. His studies of infrared radiation required him to use containers of completely pure air. He
optics / Physics / Quantum Mechanics / etc.
How Things Work: Lasers
You know, I have one simple request. And that is to have sharks with frikkin laser beams attached to their heads! ~Dr. Evil Always look on the bright side …unless you’re holding a laser pointing device. ~Unknown The laser is, without a doubt, one of the most ubiquitous, archetypal technologies of modern times. And it is one of the most direct applications of quantum mechanics. But how do lasers work? It All Starts In The Atom The story starts deep within the atom. I’ve previously discuss the fact that particles are waves and that this forces electrons to have
Physics / Science And Math
Refraction: (How We See) Through the Looking Glass
We do not see the lens through which we look. ~Ruth Benedict I was recently asked to explain refraction using quantum mechanics. To really understand this on the quantum level requires understanding a field called “quantum electrodynamics,” which was invented independently by Richard Feynman, Sin-Itiro Tomonaga, and Julian Schwinger (and for which they all shared a Nobel prize). Unfortunately, I don’t know very much about quantum electrodynamics, so I can’t explain this the way a particle physicist or condensed matter physicist might. I can however, give a “pseudoclassical” model that was invented around the turn of the twentieth century…right