using quantum photonics to create optical frequency combs
DESCRIPTION
Using Quantum Photonics to Create Optical Frequency combs. Tobias J. Kippenberg. The problem of the “whispering gallery”: observation of Lord Rayleigh in St. Paul Cathedral (London)* *L. Rayleigh. Acoustic Whispering Gallery Mode. diameter of a human hair ~100 µm. - PowerPoint PPT PresentationTRANSCRIPT
Using Quantum Photonics to Create Optical Frequency
combsTobias J. Kippenberg
The problem of the “whispering gallery”: observation of Lord Rayleigh in St. Paul Cathedral (London)**L. Rayleigh
Acoustic Whispering Gallery Mode
A photon storage time of 1 micro-second implies that the Light can travel up to 1 km inside a glass torus!
𝜏 h𝑃 𝑜𝑡𝑜𝑛>1𝜇𝑠𝑒𝑐𝑜𝑛𝑑
diameter of a human hair~100 µm
Coupling both to-and-from a 80m microtoroid on a chip
taper-microcavity junction exhibits extremely high ideality (coupling losses <0.3%)
Pin40 m
1/R
Coupling light into a microresonator
Just like a Guitar string has several vibrational modes, an optical microresonator has many optical modes
Silica Resonator (1)
Using Quantum Photonics to creat frequency combs
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At high intensities the interaction becomes nonlinear leading to «twin» photon generation
𝜔 𝐼=𝜔𝑝+ Δ𝜔𝑆=𝜔𝑝− Δ
PrismPump laser
Energy conservation requires
The Nobel Prize in Physics 1981Nicolaas BloembergenNonlinear Optics
Generating a frequency comb from a microresonator
Optical microresonator
Optical fiberPump laser
A frequency comb
Comb generation mechanism
Twin Photon generation
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wp1 ws
wi
Comb Generation Mechanism
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wpws
wi
Twin photon generation
Der Entstehungsprozess: Zwillingphotonen
Twin photon generation
Generating a frequency comb in an optical microresonator
Optical frequency comb
𝜔𝑝+ Δ𝜔𝑝+2 Δ𝜔𝑝+3 Δ𝜔𝑝𝜔𝑝− Δ𝜔𝑝− 2 Δ𝜔𝑝− 3 Δ
Δ
The perfectly equidistant arrangement is called on optical frequency comb
Δ Δ Δ ΔΔ
Microresonotor frequency comb
An octave spanning optical spectrum is generated from a single laser frequency
Optical frequency combs
Nobel Prize Physics 2005: “for their contributions to the development of laser-based precision spectroscopy, including the optical frequency comb technique"
HzWith an optical frequency combs an unknown optical frequency can be determined accurately measured
𝜔𝑜𝑝𝑡𝑖𝑞𝑢𝑒≈ 1015𝐻𝑧𝑇 𝑝𝑒𝑟𝑖𝑜𝑑≈ 10− 14 𝑠𝑒𝑐 .
Why are frequency combs interesting?
Frequency combs allow to create very accurate optical atomic clocks. Clocks that loose less than 1 second in the age of the universe of 14 Billion years…
Mode locked lasers for frequency comb generation
Ronald Holtzwarth, TWH
October 2005
T. Herr et al. Nature Photonics 2012 (July)
Frequency combs on a chip
MgF2
More than 1000 comb lines that are perfectly equidistant generated from a single laser…
Advantages of microresonator frequency combs
Vorteile:
- Very compact compact comb generator
- The distance between comb teeth is very large
Microresonator frequency combs as channel generators
Fiber optical communication uses several wavelength that travel down on optical fiber spaced in frequency by ca. >40 GHz
Applications of Frequency combs in Telecommunication
Today: picture of 4 laser modules to generate 4 channels…
Future: A single microresonator can generate > 1000 channels from a single laser
Astrophysical spectrometer: searches for exoplanets
Microresonator frequency combs can assist to calibrate astrophysical spectrometers
20
First spectrometer calibration with a Microcavity
ESO‘s Very Large Telescope (VLT) in Chile X-Shooter spectrometer (in Munich)
Microcavity comb spectrum (83 GHz mode spacing) on echelle grating based spectrometer
Frequency comb assisted spectrometer calibration
X-Shooter Telescope (ESO)
Microresonator frequency combs…
Applying them in astrophysical planets searches as calibratoin tool..
…applying them in space optical clocks…
… enable them to become sources of mid IR radiation used in chemistry or pharmaceutical minitoring..
.. Linking RF to optical on a chip…