Nobel in Physics for laser optics/spectroscopy

[Martin]

This year's Nobel Prize in physics was awarded for work in optics

http://nobelprize.org/physics/laureates/2005/press.html

 

http://nobelprize.org/physics/laureates/2005/index.html

 

half to Roy Glauber (Harvard)

 

"for his contribution to the quantum theory of optical coherence"

 

a quarter each to John L. Hall (National Institute of Standards and Technology; University of Colorado)

and Theodor W. Hänsch (Max-Planck-Institut für Quantenoptik

Garching; Ludwig-Maximilians-Universität Munich)

 

"for their contributions to the development of laser-based precision spectroscopy, including the optical frequency comb technique"

__________

[mezarashi]

Wow, after reading that brief, you can realize of the great great potential all of this work allows for. The precision laser also sounds like really great stuff. I thought the blue laser and Intel's silicon-based laser was exciting, but this just beats it all.

[Martin]

Wow, after reading that brief, you can realize of the great great potential all of this work allows for. The precision laser also sounds like really great stuff. I thought the blue laser and Intel's silicon-based laser was exciting, but this just beats it all.

 

Hi mezarashi

 

Is this the brief you found interesting?

http://nobelprize.org/physics/laureates/2005/info.pdf

 

There is also his more academic-sounding article---more history, more technical detail

http://nobelprize.org/physics/laureates/2005/phyadv05.pdf

 

Would you recommend either or both. Did you find something else?

[swansont]

This year's Nobel Prize in physics was awarded for work in optics

http://nobelprize.org/physics/laureates/2005/press.html

 

http://nobelprize.org/physics/laureates/2005/index.html

 

half to Roy Glauber (Harvard)

 

"for his contribution to the quantum theory of optical coherence"

 

a quarter each to John L. Hall (National Institute of Standards and Technology; University of Colorado)

and Theodor W. Hänsch (Max-Planck-Institut für Quantenoptik

Garching; Ludwig-Maximilians-Universität Munich)

 

"for their contributions to the development of laser-based precision spectroscopy' date=' including the optical frequency comb technique"

__________[/quote']

 

I was looking at the Nobel prediction thread and I thought of Ted Hänsch (my thesis advisor's advisor, whom I met at a conference about 5 weeks ago), but optical combs are fairly recent and I thought it would be a few more years before he would be considered for that.

 

There's a reasonable chance I'll get to work on optical combs in a few years, once the technology matures a bit more and you can make a clock out of it (people have already done preliminary work on frequency standards).

[Martin]

I was looking at the Nobel prediction thread and I thought of Ted Hänsch (my thesis advisor's advisor' date=' whom I met at a conference about 5 weeks ago), but optical combs are fairly recent and I thought it would be a few more years before he would be considered for that.

 

There's a reasonable chance I'll get to work on optical combs in a few years, once the technology matures a bit more and you can make a clock out of it (people have already done preliminary work on frequency standards).[/quote']

 

 

Congratulations to you Tom Swanson! I knew your work was with lasers but didnt have any idea you were thinking of optical frequency standards.

 

I see that one of the Laureates (John Hall, the guy at NIST) is one of those responsible for measuring the speed of light so accurately that in 1983 they changed over and declared the speed of light exactly

299792458 meters per second, so that the meter was thenceforth

the distance light in vacuo travels in 1/299792458 of a second.

 

eventually all standards, electrical, force, mass, will probably be based on the clock

 

so the clock will be the sovereign tool of measurement

 

(it already is de facto, I guess, but they havent made it official yet)

 

 

So you are of the Laureate-line of Hänsch!

a "henchman" in other words------he's your PhD grandfather

this is distinguished parentage, now you will have to struggle to retain

your modesty for a while

[Martin]

About Nobel lineage, see

 

http://www.physcomments.org/wiki/index.php?title=Genealogy::nobel

 

It turns out that Lee Smolin, of Quantum Gravity fame, is a direct linear descendent of Max Born

 

Lee Smolin's advisor was

Sydney Coleman, whose advisor was

Murray Gell-Mann, whose advisor was

Victor Friedrich Weisskopf, whose advisor was Max Born...

 

Alejandro Rivero derived the family tree at Wiki from (I think) this source:

http://www.genealogy.math.ndsu.nodak.edu/html/search.phtml

[CPL.Luke]

hmm am I the only one who finds laser cooling to be a very boring field, no offense intended, I don't know to much about it so maybe I'm just talking out of ignorance and there is something incredibly fascinating in it.

[swansont]

So you are of the Laureate-line of Hänsch!

a "henchman" in other words------he's your PhD grandfather

this is distinguished parentage' date=' now you will have to struggle to retain

your modesty for a while[/quote']

 

Many of my colleagues in atomic physics can trace their lineage through Ramsey and Rabi. But now I have a lineage, too!

[swansont]

hmm am I the only one who finds laser cooling to be a very boring field, no offense intended, I don't know to much about it so maybe I'm just talking out of ignorance and there is something incredibly fascinating in it.

 

 

No. I imagine there might be as many as three of you that find it boring.

[CPL.Luke]

hmm I suppose I am just ignorant of what its hook is.

[swansont]

hmm I suppose I am just ignorant of what its hook is.

 

You get to play with lasers, first of all.

 

There are so many areas of physics, and you go where your interest lies. I hope you understood that I was kidding before - there are areas of physics that I find uninteresting, so it's perfectly reasonable that some people aren't going to find laser cooling interesting.

[Locrian]

hmm I suppose I am just ignorant of what its hook is.

 

I know how you feel! I used to think every part of physics was boring except astrophysics. That was my love. However, I took a class as an undergrad in lasers intending to learn more about spectroscopy - I found it absolutely fascinating. Every bit as much as astrophysics, or more. I was entirely ready to ditch my old crush for a new one. I never got the chance though, because I was taken away to something entirely different.

 

Luckily, this process has repeated itself for everything I've worked in: materials sciences, crystal growth, cutting tools and most areas I touched on along the way. Recently I've started just randomly looking up physics departments, finding something that sounds boring and studying up on it. So far they've usually ended up interesting. I've done this with quantum dots, decoherence, superconductivity and more.

 

So maybe me and you just need to spend a bit more time with the fundamentals in this case.

[mezarashi]

Hi mezarashi

 

Is this the brief you found interesting?

http://nobelprize.org/physics/laureates/2005/info.pdf

 

There is also his more academic-sounding article---more history' date=' more technical detail

http://nobelprize.org/physics/laureates/2005/phyadv05.pdf

 

Would you recommend either or both. Did you find something else?[/quote']

 

Yes, I read the supplementary article, not the technical one. Usually those are very difficult to read, unless you are of course in the research field and honestly it didn't make much sense to me at this point.

 

The prize is somewhat a new inspiration for me to pursue research in photonics. Fortunately and coincidentally, I am already majoring in photonics at undergraduate level, and alot of factors have strongly pursuaded me to continue to the graduate level. I'll definitely be looking into that the potential of quantum optics and I'm already talking a bit about it with my optoelectronics professor. I just feel very intrigued by the potential of optics and how it can revolutionize our next generation of electronics and of course, way of life.

[Martin]

Yes, I read the supplementary article,..

 

You or someone you know may be interested in two free-online articles by Ted Hänsch

 

http://www.nature.com/nature/journal/v436/n7048/full/nature03851.html

 

and maybe even more interesting is this one

http://www.nature.com/nature/journal/v416/n6877/full/416233a.html

 

Optical frequency metrology

 

Th. Udem, R. Holzwarth and T. W. Hänsch

 

Abstract

Extremely narrow optical resonances in cold atoms or single trapped ions can be measured with high resolution. A laser locked to such a narrow optical resonance could serve as a highly stable oscillator for an all-optical atomic clock. However, until recently there was no reliable clockwork mechanism that could count optical frequencies of hundreds of terahertz. Techniques using femtosecond-laser frequency combs, developed within the past few years, have solved this problem. The ability to count optical oscillations of more than 10^15 cycles per second facilitates high-precision optical spectroscopy, and has led to the construction of an all-optical atomic clock that is expected eventually to outperform today's state-of-the-art caesium clocks.

-------end quote------

 

being able now to count oscillations of over ONE QUADRILLION CYCLES PER SECOND is very nice.

 

timekeeping is very important because many things are based on it

 

for example the practical CURRENT AND VOLTAGE standards established in 1990 are based on measuring frequency.

 

all kinds of measuring technology ("metrology") depends on atomic clocks.

 

so if Haensch can build a better atomic clock then this raises the level for everybody----it floats everybody's boat.

[swansont]

so if Haensch can build a better atomic clock then this raises the level for everybody----it floats everybody's boat.

 

Technically it's a frequency standard, and you still have the issue of transmitting the information. But the potential certainly is there for much better timing. One limitation is that currently these would all be secondary standards, since the second is defined in terms of a microwave transition in cesium - so everything depends on how well you can measure the frequency of your transition in terms of the cesium frequency.

[CPL.Luke]

is it possible to make a more up to date standard, in place of the cesium standard?

[Martin]

is it possible to make a more up to date standard, in place of the cesium standard?

 

according to a special issue of the SciAm that came out in September 2002, devoted to time, clocks, frequency standards etc, the answer is yes and there are several new types of atomic clock in the works that have some hope of getting better accuracy. Swanson would know what the most promising ones are.

 

To the best of my memory one of the types of atomic clock that SciAm mentioned was hydrogen (instead of cesium)

 

bear in mind that this is just the SciAm and my imperfect memory.

 

there is sure to be something better though----some higher frequency transition----as soon as they develop a way to count a faster signal they up the bar

[swansont]

according to a special issue of the SciAm that came out in September 2002' date=' devoted to time, clocks, frequency standards etc, the answer is yes and there are several new types of atomic clock in the works that have some hope of getting better accuracy. Swanson would know what the most promising ones are.

 

To the best of my memory one of the types of atomic clock that SciAm mentioned was hydrogen (instead of cesium)

 

bear in mind that this is just the SciAm and my imperfect memory.

 

there is sure to be something better though----some higher frequency transition----as soon as they develop a way to count a faster signal they up the bar[/quote']

 

That was a pretty good issue. One of the authors for it ran his work past my boss, so I got to help edit it and clean up a few mistakes.

 

A key here is the difference between accuracy and precision. The second is defined by the hyperfine transition in Cesium, so accuracy of a standard using another transition is limited in part by how well that other frequency has been measured. However, that other transition may be much more precise (meaning that you can measure it with a smaller uncertainty).

 

A hydrogen maser is a really good clock in the short-term, but is not a primary frequency standard. However, at some point you don't care what it's frequency is, as long as the frequency is not changing over time - then you can compare it with your cesium reference to make sure that it isn't changing over time, too. So a higher-precision tool would find a use even if it were not initially very accurate.

 

The current best (in accuracy and precision) frequency standards are atomic fountains, which have replaced atomic beams. Labs that have primary frequency standards typically have an ensemble of clocks so they can do their measurements and use the clocks as a flywheel of sorts to maintain the information until they make another measurement. That's a key difference between a clock and a frequency standard - you can't turn a clock off, since it measures phase.

 

The way that the femtosecond laser comb fits in is that the comb frequencies are, or can be, separated by some frequency in the RF or microwave, which we can count. The comb also ties in very precisely to the optical frequencies so you can use them to transfer the precision of an optical transition down to the RF. One key, discovered by Haensch, is that the individual frequencies in the comb are phase-stable, and that it's possible to "lock" all of the frequencies in place.