Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

"On-the-fly" spectroscopy with a diode laser and a frequency comb

01.09.2009
MPQ scientists achieve high precision optical broadband spectroscopy by applying frequency comb technique to tunable diode lasers.

The research field of optical spectroscopy has already attracted attention of generations of scientists, starting with Fraunhofer's discovery of dark lines in the sun spectrum in 1814 followed by the work of Kirchhoff and Bunsen in 1859 explaining these lines as absorption of light in atoms and molecules.


Light confinement in microcavities: Quartz glass microresonators on a silicon chip allow to store light for long times corresponding to more than 1 million round trips of photons within the resonator. Depending on its wavelengths (color), the light is confined closer to the rim or more inside the resonator, respectively.

Within the last decade, the invention of optical frequency combs has revolutionized the field of spectroscopy and enabled measurements with previously unattainable precision. Now, MPQ scientists (from the "Laboratory of Photonics & Quantum Measurements" lead by EPFL tenure track professor T.J. Kippenberg) developed a novel measurement scheme for broadband and fast measurements of optical spectra utilizing the accuracy of an optical frequency comb and transferring it to an easy-to-use tunable diode laser. (Nature Photonics, AOP, August 2009, DOI:10.1038/nphoton.2009.138)

These tunable diode lasers can be swept in frequency (i.e. the "color" of the laser can be changed) to measure the spectral response of anything of interest, for example light absorption in gases but also the response of photonic elements in the growing field of nano-photonics. However, sweeping the frequency of a tunable diode laser alone does not allow for precise spectroscopic measurements, unless the instantaneous frequency of the diode laser at a certain time is known precisely.

Here, the new measurement scheme comes into play, enabling an "on-the-fly" calibration of the sweeping diode laser using an optical fiber laser based frequency comb. The achieved precision of the spectroscopic measurement is better than 1 MHz (note that the frequency of the laser light is around 200 THz, corresponding to a relative accuracy of 5x10 to the -9).

As a first application, the newly developed spectroscopy scheme has been used by MPQ scientists Pascal Del'Haye and Dr. Arcizet to obtain absorption spectra of on-chip monolithic optical microresonators made of fused silica (so called microtoroids). These measurements allowed for the first time to analyze dispersion properties of these devices (conventional spectroscopy methods had so far failed due to the extremely narrow (sub-MHz) absorption lines of the microresonators). Numerical simulations as well as the experimental results show that the mode structure of microtoroids is extremely uniform, i.e. the optical modes that are supported by the device are nearly spaced equidistant. This surprising result is a consequence of the spatial shape of the optical modes within the resonator (leading to "red" modes at low frequencies being more confined inside the resonator than "blue" modes at high frequencies) that is partly compensated by a different material dispersion for different light frequencies (here, the "red" modes are travelling slower, i.e. the resonator seems to be larger for the "red" modes). "The small total dispersion of microtoroids makes them a well suited device for applications in microphotonics as well as for frequency comb generation via nonlinear optical
frequency conversion", states Prof. Tobias Kippenberg.
A patent of the new technique has been filed together with Max Planck Innovation. [PD] / Olivia Meyer-Streng
Original Publication:
P. Del'Haye, O. Arcizet, M. L. Gorodetsky, R. Holzwarth & T. J. Kippenberg
Frequency comb assisted diode laser spectroscopy for measurement of microcavity dispersion

Nature Photonics, Advance Online Publication, August 2009, DOI:10.1038/nphoton.2009.138

Nature Photonics "News and Views", T. Schibli, Colorado University, USA
Optical spectroscopy: Clever calibration, doi:10.1038/nphoton.2009.150
Contact:
Prof. Dr. Tobias Kippenberg
Ecole Polytechnique Fédérale de Lausanne, CH1015, Switzerland and
Max Planck Institute of Quantum Optics, 85748 Garching, Germany
Phone: +49 - 89 / 32905 727
Fax: +49 - 89 / 32905 200
e-mail: tobias.kippenberg@mpq.mpg.de
Pascal Del'Haye
Max Planck Institute of Quantum Optics
Phone: +49 - 89 / 32905 284
Fax: +49 - 89 / 32905 200
e-mail: pascal.delhaye@mpq.mpg.de
Dr. Olivia Meyer-Streng
Max Planck Institute of Quantum Optics
Press & Public Relations
Phone: +49 - 89 / 32905 213
Fax: +49 - 89 / 32905 200
e-mail: olivia.meyer-streng@mpq.mpg.de

Dr. Olivia Meyer-Streng | Max-Planck-Institut
Further information:
http://www.mpq.mpg.de/k-lab/

More articles from Physics and Astronomy:

nachricht Witnessing turbulent motion in the atmosphere of a distant star
23.08.2017 | Max-Planck-Institut für Radioastronomie

nachricht Heating quantum matter: A novel view on topology
22.08.2017 | Université libre de Bruxelles

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

Scientists discover species of dolphin that existed along South Carolina coast

24.08.2017 | Life Sciences

The science of fluoride flipping

24.08.2017 | Life Sciences

Optimizing therapy planning for cancers of the liver

24.08.2017 | Medical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>