The 2018 Nobel Prize In Physics...
Posted by on Tuesday, October 2, 2018
The big day has arrived, and the Nobel committee has now announced the recipients of the 2018 Nobel Prize in Physics. And as I predicted, this year they have gone with a technological development rather than work in pure science. However the research that resulted in this year's prize is still pretty amazing.
I must also start with a disclaimer here that this research is well outside my own specialist field of theoretical and mathematical physics / astrophysics / particle physics. As such I can only give a very rough overview of the work that the three recipients have done in the field of laser physics. (And I should also add here that I am going to focus solely on the research here, and avoid some of the unfortunate side issues and politics that seem to have arisen in some of the reporting on the selection and awarding of this year's prize)
There are actually two separate but closely related topics in laser physics that have been recognized this year. The first of these is the development of the optical tweezers by Arthur Ashkin. Most people are familiar with the use of tweezers in everyday usage. They allow us to grab and manipulate tiny objects that would be otherwise to small to work with. However at some small scale, it is no longer possible to use a physical object such as tweezers. In particular it would be impossible to manipulate single molecules or atoms using a tool comprised of billions of atoms and molecules. Therefore a new technology was needed.
The new technology that Ashkin and others developed was the optical tweezers or laser tweezers. By using multiple laser beams, scientists were able to trap atoms and molecules in between two or more streams of photons. By adjusting the laser emitters, these atoms can be moved around and manipulated. When other technologies such as scanning electron microscopes are added to the setup, scientists are able to create quite intricate and complicated patterns of atoms and molecules, as well as perform experiments that would have been impossible just a few decades ago. By the late 1980s the method had been developed to the point where scientists could manipulate living viruses and bacteria without harming them, simply by using precise laser beams. And so the optical tweezers are certainly a major scientific advance not only in physics but also in chemistry and biology, and are certainly worthy of a share of the Nobel Prize.
Meanwhile, the other half of the Nobel Prize this year was given to Gerard Mourou and Donna Strickland for their work in developing high intensity, ultra-fast pulsed lasers. A traditional laser takes a certain amount of time to "turn on", as it requires first pumping atoms into excited states before the laser can begin triggering their decay, which then creates the characteristic monochromatic beam of light. This startup time makes it impossible for a traditional laser to create short bursts, or pulses of light.
The methods developed by Mourou and his graduate student, Strickland, are quite technical and too complicated to give a proper description of here. However they used a novel new technique to speed up the switching of the laser, which created not only a very fast startup and cool down but also a very high intensity beam. The method is known as chirped chirped pulse amplification, and essentially involves first creating a long, low intensity laser pulse using traditional methods. Once the pulse has been generated, they compress it in such a way that the start of the pulse is slightly slowed and the back of the pulse is slightly accelerated, resulting in the production of a much short pulse that also has a higher intensity due to the all of the original laser energy being compressed into a much smaller region. This method allowed them to generate very short, rapid pulses of high intensity laser energy that could be used for a number of practical applications. The most significant of these for the general public has been the development of laser eye surgery, which is now commonly used to correct vision defects in patients. This technique has been so powerful that even thirty three years after they first published their results, scientists are still exploring all of the potential applications for such amplified laser pulses.
And so that is my brief summary of the two fascinating pieces of laser physics research that earned this year's Nobel Prize. They are very different techniques with very different applications, but they are both major advances in the science and technology of laser beams, and have both had a significant impact not only one the scientific world but on society in general.
So congratulations to the three recipients of this year's prize, and may they and their students continue this amazing research that has so changed our understanding of light and lasers!
I must also start with a disclaimer here that this research is well outside my own specialist field of theoretical and mathematical physics / astrophysics / particle physics. As such I can only give a very rough overview of the work that the three recipients have done in the field of laser physics. (And I should also add here that I am going to focus solely on the research here, and avoid some of the unfortunate side issues and politics that seem to have arisen in some of the reporting on the selection and awarding of this year's prize)
There are actually two separate but closely related topics in laser physics that have been recognized this year. The first of these is the development of the optical tweezers by Arthur Ashkin. Most people are familiar with the use of tweezers in everyday usage. They allow us to grab and manipulate tiny objects that would be otherwise to small to work with. However at some small scale, it is no longer possible to use a physical object such as tweezers. In particular it would be impossible to manipulate single molecules or atoms using a tool comprised of billions of atoms and molecules. Therefore a new technology was needed.
The new technology that Ashkin and others developed was the optical tweezers or laser tweezers. By using multiple laser beams, scientists were able to trap atoms and molecules in between two or more streams of photons. By adjusting the laser emitters, these atoms can be moved around and manipulated. When other technologies such as scanning electron microscopes are added to the setup, scientists are able to create quite intricate and complicated patterns of atoms and molecules, as well as perform experiments that would have been impossible just a few decades ago. By the late 1980s the method had been developed to the point where scientists could manipulate living viruses and bacteria without harming them, simply by using precise laser beams. And so the optical tweezers are certainly a major scientific advance not only in physics but also in chemistry and biology, and are certainly worthy of a share of the Nobel Prize.
Meanwhile, the other half of the Nobel Prize this year was given to Gerard Mourou and Donna Strickland for their work in developing high intensity, ultra-fast pulsed lasers. A traditional laser takes a certain amount of time to "turn on", as it requires first pumping atoms into excited states before the laser can begin triggering their decay, which then creates the characteristic monochromatic beam of light. This startup time makes it impossible for a traditional laser to create short bursts, or pulses of light.
The methods developed by Mourou and his graduate student, Strickland, are quite technical and too complicated to give a proper description of here. However they used a novel new technique to speed up the switching of the laser, which created not only a very fast startup and cool down but also a very high intensity beam. The method is known as chirped chirped pulse amplification, and essentially involves first creating a long, low intensity laser pulse using traditional methods. Once the pulse has been generated, they compress it in such a way that the start of the pulse is slightly slowed and the back of the pulse is slightly accelerated, resulting in the production of a much short pulse that also has a higher intensity due to the all of the original laser energy being compressed into a much smaller region. This method allowed them to generate very short, rapid pulses of high intensity laser energy that could be used for a number of practical applications. The most significant of these for the general public has been the development of laser eye surgery, which is now commonly used to correct vision defects in patients. This technique has been so powerful that even thirty three years after they first published their results, scientists are still exploring all of the potential applications for such amplified laser pulses.
And so that is my brief summary of the two fascinating pieces of laser physics research that earned this year's Nobel Prize. They are very different techniques with very different applications, but they are both major advances in the science and technology of laser beams, and have both had a significant impact not only one the scientific world but on society in general.
So congratulations to the three recipients of this year's prize, and may they and their students continue this amazing research that has so changed our understanding of light and lasers!
I am a theoretical physicist & mathematician, with training in electronics, programming, robotics, and a number of other related fields.
